Proceedings Undergraduate Research Program

Hispanic Serving Institutions Education Grant Program

Year 2, Vol. 1 (2005)

Participating Faculty and Undergraduate Students

D Paul Randel Folding Jonathan González EspinoDr. Héc or San iago Anadón Kennet AponteD Teodoro Ru z López Sully M Morales Dr Elide Valencia Chin Axel Ramírez Made aD Angel Cus odio Gonzalez Edna Be ancouDr Miguel Muñoz José N FelicianoD Abne Rodríguez Carías Luis Cruz A royo

Neddie Maldonado

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1

Table of Content

is Cruz Arroyo, Rebeka Sanabria Leon, Myrna Alameda, and Abner A. Rodríguez ..……………………………1

sé Noel Feliciano Maldonado and Miguel A. Muñoz………………………………………………………………………. 12

xel O. Ramírez Madera and Elide Valencia …………………………………………………………………………………… 19

nathan González, Paul Randel, Abner Rodríguez, Héctor Santiago, and Elide Valencia .………………….. 25

litter materials on performance, carcass

enneth H. Aponte, Héctor L. Santiago, and Abner A. Rodríguez ……………………………………………………..29

obic stability of silage made of hay hydrated with crude milk or

dna Betancourt,

Composting goat mortalities Lu Sequential extraction of P available fractions in soils amended with animal manure Jo Dairy compost application and its effect on growth of Zoysia turfgrass A Effect of shrimp residue supplementation on intake and digestibility of grass hay Jo The use of paper products as alternativequality, and footpad lesions of broilers K Quality and aerantibiotic milk E Angel A. Custodio and Abner A. Rodríguez ………………………………………………………. 34

stability of mango (Mangifera indica) and

eddie Cruz Maldonado, Suzika Pagán Riestra, and Abner A. Rodríguez Carías ………………………………….43

of milk waste solids from a milk processing plant for potential use in

ully M. Morales, Teodoro Ruiz, Héctor L. Díaz ……………………………………………………………………………… 51

te Professor, Department of Animal Industry, University s

Fermentation characteristics and aerobicstarfruit (Avherroa carambola) residues N Fermentationanimal feed

S

This report was coordinated by Abner A. Rodríguez-Carías, Associaof Puerto Rico, Mayagüez Campu

2

Composting goat mortalities

Luis ez1

2Department of Agronomy and Soils, Uni erto Rico, Mayagüez Campus

his type of aste. Further studies are needed to evaluate the use of this compost as an organic fertilizer.

de la mortandad en ncas caprinas. Estudios sobre su valor como fertilizante orgánico deben realizarse.

this type of waste has been the subject of research effort (Sanabria et al., 2003). Eldridge (1996)

Cruz Arroyo1, Rebeka Sanabria Leon1, Myrna Alameda2 and Abner A. Rodrígu1Department of Animal Science, University of Puerto Rico, Mayagüez Campus

versity of Pu

Abstract The objective of this study was to evaluate the composting process for the disposal of goat mortalities. Treatments consisted of composting yard trimmings alone (YT; control group) and YT with goat mortalities (GM), evaluated in seven phases. Mixtures were weighted in a 2:1 proportion (YT:GM) and placed in composting bins of identical dimensions (3 ft3). Moisture level was adjusted to 60% throughout the seven phases. Temperature was recorded daily to determine the time (d) needed to reach the first and second heat cycles. Composting characteristics (pH, C:N ratio, OM, IM, and N concentration) were measured at 0 d, at the peak of the first and second heat cycles, and at maturation (0, 20, 50 and 70 d). During the first heat cycle, bacterial isolates were cultivated and identified using the Biolog System. Chemical composition was analyzed using a 2 (layers of GM) x 7 (composting phases) factorial design and ANOVA procedure of SAS. Only the GM treatment exhibited thermophillic temperatures. After the first heat cycle, the pH was neutral for YT and ranged from 6.8 to 8.3 for GM throughout the process. There was a decrease in OM and C, and an increase in IM and N in both treatments at all sampling times. At 70 d of maturation C:N values were similar between treatments, but were lower (P<0.05) than the values at the beginning of the process. At the first heat cycle different populations of bacteria could be identified. Goat mortalities compost was shown to be an alternate method for the disposal of tw Resumen Se realizó un experimento con el objetivo de evaluar el proceso de composta como alternativa para disponer de mortandad en fincas caprinas. Los tratamientos fueron residuos de jardinería (RJ) o éstos mezclados con cabros muertos (RJC) durante siete fases del proceso. La mezcla RJC fue pesada en una proporción 2:1 y colocada en estructuras para compostar con dimensiones idénticas (3’3). La humedad fue ajustada al inicio y durante todo el proceso de fermentación a 60%. La temperatura fue monitoreada diariamente con termómetros colocados en el centro del material a degradarse para determinar el tiempo demorado en alcanzar el primer y segundo ciclo de calor. Las características de la composta (pH, razón C:N, MO, MI, y el contenido de N) fueron determinados al inicio, durante el primer y segundo ciclo de calor y a los 0, 20, 50 y 70 d de maduración del material compostado. Durante el primer ciclo de calor, se aislaron y cultivaron bacterias para ser identificadas por el sistema Biolog. La composición química fue analizada mediante un diseño completamente aleatorizado con arreglo factorial de tratamientos 2 (RJ ó RJC) * 7 (fases). Temperaturas termofílicas se observaron solamente en el tratamiento RJC. Después del primer ciclo de calor, el pH fue neutro para la composta de RJ y durante todo el proceso de compostación se observó una variación en pH de 6.8 a 8.3 en RJC. En ambos tratamientos los contenidos de MO y C disminuyeron pero los de MI y N aumentaron a través del proceso. Después de 70 d de maduración la razón C:N fue similar para ambos tratamientos, pero menor que la razón observada al principio del proceso. Durante el primer ciclo de calor diferentes poblaciones de bacterias fueron identificadas. En resumen, el proceso de composta representa una alternativa para la disposición fi Introduction In 1998 Puerto Rico had 495 goat farms with a total of 9157 animals. The normal rates of mortality are

10% of the newborn kids before weaning and 5% of the total herd. Currently these organic residues

(dead goats) are buried, incinerated, or disposed of in landfills causing air, land and water pollution.

Therefore the application of biological procedures and technology for the reduction and stabilization of

3

documented composting as a biological procedure for rapid animal tissue decomposition with excellent

results. Composting refers to the biological decomposition of organic matter resulting in a stable humus-

like product. The process is due to microorganisms, generally bacteria, fungi and actinomycetes

(Trautmann and Olynciw, 2003; Epstein, 1997), that breakdown organic matter as energy sources. The

microbial metabolism creates heat capable of destroying pathogenic organism if they are exposed to the

high temperatures for a specific period of time (Morse, 2001).

To understand the whole process it is important to know with precision the microorganisms responsible

for most of the degradation. The identification of the dominant microorganism population in the different

stages of degradation can help in future investigations aimed ar reducing the time of organic matter

breakdown and enhancing the compost quality. Researchers have used several protocols based on

random amplification polymorphic DNA (Zhang et al., 2002), polymerase chain reaction assays (Peters et

al., 2000; Sanabria et al., 2003), phospholipids fatty acid profiling and carbon source utilization studies

(Carpenter-Boggs et al., 1998) to detect the presence or absence of pathogens and identify the microbial

population responsible for the organic matter degradation in the compost (Sanabria et al., 2005). The

objectives of this research is to evaluate the composting process as an alternative for disposing of dead

goats from local farms and identify the principal microorganism involved in the first stage of the process.

Materials y Methods

Goat mortalities (GM) were obtained from the Small Ruminant Program of the University of Puerto Rico,

in Mayaguez. Yard trimmings (YT) were obtained from the composting facilities located at the Alzamora

Farm, University of P.R. Yard trimming compost and a mixture of goat mortalities and yard trimming

compost were evaluated. Both treatments had three replicates, and the materials were placed in identical

3ft3 composting bins for a total of six composts. In the GM treatment, goat mortalities were placed

between 18” layers of YT in a 2:1 proportion. The compost piles were hydrated to obtain approximately

an initial moisture content of 60%, which was maintained over the entire process.

In each treatment temperature was monitored daily with composting thermometers. As shown in Figure 1

the composting process was divided into seven phases. Composting phases 1 and 2 were considered to

finish once the temperature dropped 10˚ F from the maximum value recorded in the first and second

heat cycles, respectively. Once the composting temperatures stabilized with the environmental

temperatures the compost had reached maturation. Observation continued after maturation at days 0,

20, 50 and 70 to track any change occurring in the compost.

4

Chemical Analysis Triplicate samples from each original material (composting phase O) were obtained to determine initial C

and N content, C:N ratio, organic matter (OM) and inorganic matter (IM) contents using standard

procedures (AOAC, 190). In the seven composting (Figure 1) phases four core samples were obtained

from each treatment replication.

Samples for each treatment and composting phase were collected, after turning and weighting the

compost piles, and analyzed to determine pH and chemical composition as described for the original

material at stage 0. Data were analyzed according to a completely randomized design with a 2 (layer of

GM; none or single) by 7 (composting phases) factorial arrangement (Steel and Iorrie 1990) using the

General Linear Model subroutine of SAS (1990). Treatment means showing significant difference in the

ANOVA were ranked using the Tukey test of SAS (1990). All statement of significance are based on the

probability level of .05 unless otherwise noted.

Biological Analysis

Samples for microbial identification were taken from both treatments only at the first heat cycle as

described for the chemical analysis. Samples were homogenized and diluted experimentally several times

from 10-1 to 10-10. Each dilution was grown in Triptic Soy Agar. Thirty bacterial isolates were chosen

randomly from both treatments, classified with Gram and Malakite Stains and identified with the Biolog®

System kit. Bacterial isolates were raised on TSA and Biolog Universal Growth (BUG) media. The 24

growing cultures were then suspended in GN/GP inoculating fluid, adjusted to required optical density

and inoculated into the 96-well Biolog Plates. Plates were incubated at 30˚ C for 24 hours. Color

Figure 1. Sampling times during the composting

Tem

pera

ture

(°

F)

Stage 1 (1st Heat Cycle) Stage 2 (2nd Heat Cycle)

Stage 0 (Initial phase)

Stage 3 (Start of maturation) Stages 4, 5 and 6

(20, 50 and 70 d of maturation)

Days of Composting

5

development patterns in the Biolog plates’ well was compared to the database until the bacterial isolates

were identified at species level.

Results and Discussion

Chemical Analysis

f r f

The pH values showed an interaction between treatment and composting phase (Table 1). The pH value

in YT compost remained neutral during the entire composting process. However, pH in GM compost

differed (p<0.05) between phases varying from slightly alkaline (phases 1 and 2), to neutral (phases 3,

4, 5) and slightly acid (phase 6). Previous studies (Sanabria et al. in 2004) showed similar trends in pH

values for slaughterhouse waste composts. According to the Journal of the Woods End Research

Laboratory pH values from 6.0-7.5 are recommended in the composting process. Lowering a high pH will

help to control ammonia volatilization and reduce odors, as it will favor a balanced microbial population.

This was evident in the first and second stages, when the pH was high and ammonia odor was present.

Table 1. pH for the YT and GM compost in the seven composting stages

Means with di ferent supersc ipts di fer (P<.05)

Treatments

Component Composting Stage YT compost GM compost

pH 1 2 3 4 5 6

7.39bcd

7.72ab

7.84ad

7.86ad

7.34abc

7.64abc

8.29ª 8.26ª 7.41bcd

7.70ab

7.01bc

6.85c

Chemical composition data showed no difference between treatments but differences between

composting stages. In both treatments the C and OM contents decreased (P<0.05), while IM increased

(P<0.05) over the composting process (Figures 2, 3 and 4, respectively). Even though the C:N ratio, was

initially higher (45.48:1 for YT and 35.26:1 for GM ) than the recommended (25:1 to 30:1; Rink et al.,

1992) in both treatments it trended to decreased, reaching a final value of 21.28 for the YT compost and

14.32 for the GM compost (Figure 5). Nitrogen percentage also showed similar trends between

treatments and variability among composting phases (Figure 6). All these chemical changes indicate

progressive decomposition of the material.

Thermophillic temperatures were reached only in GM compost. The temperature in YT compost stayed

mesophillic during the entire process but remained higher than the environmental temperature and

evidenced heat cycles (Figure 7). The weight of the composting material decreased fom 36.89 and 46.04

Kg at stage 0 to 13.71 and 18.07 Kg at the end of maturation for YT and GM compost, respectively

6

(Figure 8). The original material was mostly, if not completely, decomposed in both treatments including

all animal tissues, except bones, in the GM compost (Figure 9).

30

35

40

45

50

55

0 1 2 3 4 5

Composting stages

Car

bon

(%)

GM compost YT compost

a

a

ab

abab

ab

bc

bc

bc

bc

bc

bc

c

c

6

Figure 2. Carbon percent for the YT and GM compost in the seven composting stages

Means with di erent superscripts di er (P<.05)

7

60

65

70

75

80

85

90

95

100

0 1 2 3 4 5 6

Composting stages

Org

anic

Mat

ter (

%)

GM compost YT compost

a

a

aaa

a

ab

ab

ab

ab

ab

ab

b

b

ff ff

f r f

Figure 3. Organic matter percent for the YT and GM compost in the seven composting stages Means with di ferent supersc ipts di fer (P<.05)

5

10

15

20

25

30

0 1 2 3 4 5

Composting stages

Inor

gani

c M

atte

r (%

)

GM compost YT compost

a

a

aa

a ab

ab

ab

abab

ab

a

b

b 6

Figure 4. Inorganic matter percent for the YT and GM compost in the seven composting stages Means with dif erent superscripts differ (P<.05) f

0

5

10

15

20

25

30

35

40

45

50

0 1 2 3 4 5

Composting stages

C:N

6

GM compost YT compost

a

a

b

b

cbc

bc

bc

bc

c

a

a

c

c

Figure 5. Carbon to nitrogen ratio for the YT and GM compost in the seven composting stages Means with different superscripts differ (P<.05)

8

0.50

1.00

1.50

2.00

2.50

3.00

0 1 2 3 4 5

Composting stages

Nitr

ogen

(%)

6

GM compost YT compost

a

a

a

a

b

b

cd

cd

bc

bc

cd

cd

d

d

Figure 6. Nitrogen percent for the YT and GM compost in the seven composting stages Means with d ferent superscripts d fer (P<.05)if if

0

10

20

30

40

50

60

0 20 40 60 80 100 120 140Days

Tem

pera

ture

s (C

°)

EnvironmentalYTGM

Figure 7. Temperature for the YT and GM compost in the seven composting stages

9

0

5

10

15

20

25

30

35

40

45

50

Treatments

Wei

ght o

f com

post

(kg)

Stage 0 Stage 6

Figure 8. Difference in weight of materila for YT and GM compost in initial and final stages Means with di erent superscripts dif er (P<.05) ff f

GM compost YT compost

Figure 9. Conformation difference for YT and GM compost in initial and final stages

10

Biological Analysis

r

.

t t

In the bacterial analysis 14 different microorganisms were identified during the first heat cycle (Table 2).

Most of them were gram-negative, non-enteric and positive in the oxidize test. Listonella anguillarum and

Pantoea stewartii belong to the gram-negative enteric group. The gram-positive groups consist of rods

like Tsukamu ella inchonensis and Bacillus cereus/ thuringensis, and cocci like Staphylococcus sciuri and

Macrococcus equipercicus. B. cereus/ thuringensis and Vibrio diazotrophicus were identified in both

experimental groups (GM and YT).

The fact that B. cereus/ thuringensis and Vibrio diazotrophicus were identified in both experimental

groups indicates the importance of the composting process. In 1997 Epstein reported the presence of B.

cereus in the composting process, whereas Vibrio diazotrophicus was not present. Pantoea stewartii and

Listonella anguilarum are the only bacteria of those identified that can’t grow at termophilic temperatures

(35-39°C) but the variations in temperature between treatments could have made the growth of these

species possible at some points. However, only B. thuringensis grows optically at these temperatures (40-

45°C). Bacillus cereus and Staphylococcus sciuri have a wide range of temperature, (35-45 °C, and 6.5-

46 °C, respectively) but their optimum temperature is below 40 °C (Cowan et al., 1974). Ghazifard et al.

(2001) identified in municipal solid waste compost Escherichia, Klebsiella, Aeromonas, Alcaligenes,

Enterococcus and Bacillus as dominant microorganism at initial stages. After 20 days of composting they

only identified Bacillus spp because of the termophilic temperatures.

Some of these strains are capable of being weak human pathogens. B. cereus is a ubiquitous soil

bacterium that produces toxins which damage vital organs but it is considered a weak pathogen because

only immuno-depressive patients present signs of infection. Staphilococci are considered important

human and animal pathogens responsible for causing multiple infections but the clinical significance of

Staphylococcus sciurii and Macrococcus equipercicus (closely related to genus Staphilococci) remain

controversial. Macrococcus equipercicus have been isolated from equines where they seem to form part

of the cutaneous flora.

Burkholderia glumae is a bacterial grain/ seedling rot pathogen. Pantoea s ewar ii causes a vascular wilt

of corn and some related plants. Listonella anguillarum, Acuaspirillum metamorphum, Vibrio tubiashi and

Vibrio diazotrophicus are water pathogens for fish, fresh water shellfish and bivalve mollusks. All isolated

strains, with the exception of B. glumae, P. Stewartii and V. diazotrophicus, reduce nitrates to nitrites. B.

glumae and V. diazotrophicus fix atmospheric and marine nitrogen, respectively. These results show

that the microorganisms in the compost are able to decompose all animal tissue, except bones, rapidly

without creating rotten odors. However, isolation of dominant microorganisms in the compost at different

stages could help us to make inocula to accelerate the composting process and/or enhance the compost

quality. B. cereus/ thuringensis could be important bacteria in the process; however, further studies are

needed to establish the relationship between the changing microbial population and changes in nutrient

concentrations and temperature.

11

Table 2. Bacteria isolated from YT and GM compost during the first heat cycle using the Biolog® System

99Pantoea stewartii ss stewartii100Bacillus cereus/thuringensis100Aeromomas encheleta99Burkholderia glumae99Vibrio diazotrophicus79Vibrio tubiashii98Macrococcus equipercicusYT compost

99Staphylococcus sciuri95Bacillus cereus/thuringensis99Tsukamurella inchoensis

100Vibrio diazotrophicus89Serratia plymuthica

100Alcaligenes faecalis faecalis97Listonella anguillarumGM compost

Probability (%)BacteriaTreatment

99Pantoea stewartii ss stewartii100Bacillus cereus/thuringensis100Aeromomas encheleta99Burkholderia glumae99Vibrio diazotrophicus79Vibrio tubiashii98Macrococcus equipercicusYT compost

99Staphylococcus sciuri95Bacillus cereus/thuringensis99Tsukamurella inchoensis

100Vibrio diazotrophicus89Serratia plymuthica

100Alcaligenes faecalis faecalis97Listonella anguillarumGM compost

Probability (%)BacteriaTreatment

Conclusion

The composting process is an environmentally safe alternative for disposing of dead goats on farms. The

degradation process of yard trimmings composted alone or in combination with dead animals is

characterized by heterogeneous bacterial populations.

Cited Literature AOAC. Official Methods of Analysis. 1991. Association of Official Analytical Chemists. Washington, D.C. Carpenter-Boggs, L., A.C. Kennedy, and J.P. Reganold. 1998. Use of phospholipids fatty acids and carbon source utilization patterns to track microbial community succession in developing compost. Appl. Environ. Microbiol. 64: 4062-4064 Cowan, S.T., J.G. Holt, J. Linston, R.G.E. Murray, C.F. Niven , A.W. Ravin, and R.Y. Stainer. 1974. Bergey’s Manual of Determinative Bacteriology 8th Ed. The Williams and Wilkins Company. Epstein, E. 1996. The Science of Composting. CRC Press LLC. Boca Ratón, Florida. Ghazifard, A., R. Kasra-Kermanshahi, and Z.E. Far. 2001. Identification of thermophilic and mesophilic bacteria and fungi in Esfahan (Iran) municipal solid waste compost. Waste Manag Res. 19(3): 257-261. Palma, J., R. Espinace, P. Valenzuela y M. Szanto. 1999. Reducción de los tiempos de estabilización en rellenos sanitarios operados con recirculación de lixiviados. XIII Congreso de Ingeniería Sanitaria y Ambiental-Chile. Peters, S., S. Koschisky, F. Schwieger, and C.C. Tebbe. 2002. Sccesion of microbial communities during hot composting as detected by PCR-single-strand-conformation-polymorphism-based genetic profiles of small-subunit rRNA genes. Appl. and Environ. Microbiol. 66:930-936. Rynk, R. 1992. On-Farm Composting Hand Book. NRAES-54. Itacha, NY.

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Sanabria, R., A.A. Rodríguez, and H. Santiago. 2004. Evaluating yard trimmings as a bulking agent during the composting of organic slaughterhouse waste. In: V. Popov, H. Itoh, C.A. Brebia and S. Kungolos (Eds), Waste Management and the Environment II (pp 273-279). WIT Press Southampton, Boston. Sanabria, R., A.A. Rodríguez, María Plaza, and Melvin Pagán. Evaluating composing as an alternative for the disposal of fish wastes. Sigma Xi VIII Poster Day, Mayagűez, PR. Pp2. 2003. Sanabria, R., L. Cruz, M. Alameda and A.A. Rodríguez. Chemical and biological characterization of slaughterhouse waste compost. (Submitted J. Waste Management). SAS/STAT.SAS User’s Guide (Version 6). 1990. SAS Inst., Inc., Cary, NC. Steel, R.G.D. and J.H. Torrie.1990. Principles and Procedures of Statistics; A Biometrical Approach. 2nd Ed. McGraw Hill, New York, NY. Thompson, W.H., P.B. Leege, P. Millner, and M.E. Watson. 2002. Test methods for the examination of composting and compost. U.S. Composting Council Online. http://www.tmecc.org/tmecc. Trautmann, N., and E. Olynciw. Compost microorganisms. http://cfe.cornell.edu/compost/microorg.html. Accessed July 2003. Zhang, Y.C., R.S Ronimus, N. Turner, Y. Zhang, and H.W.Morgan. 2002. Enumeration of thermophilic Bacillus species in compost and identification with a random amplification polymorphic DNA (RAPD) protocol. Syst. Appl. Microbiol. 25: 618-626.

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Sequential extraction of P available fractions in soils amended with animal manure José Noel Feliciano Maldonado1, Miguel A. Muñoz1

1Department of Agronomy and Soils, University of Puerto Rico, Mayagüez, PR Abstract Excessive amounts of available phosphorus (P) in agricultural soils can cause serious contamination of surface and groundwater resources. In soils amended with manure, significant losses of P may occur as a result of runoff and erosion. In addition to management and environmental factors, soil physical and chemical properties influence P losses. The P content of three soils with a history of intensive manure application was evaluated. Three P extractants (deionized water, 0.01 M CaCl2, and Bray-1 solution) were evaluated. The soils used were Consumo (Fine, mixed, semiactive, isohyperthermic Typic Haplohumults) and Naranjito (Fine, mixed, semiactive, isohyperthermic Typic Haplohumults), amended with chicken manure, and Soller (Clayey, mixed, active, isohyperthermic, shallow Typic Haprendolls) amended with cow manure. Six sequential 30-minutes extractions with 20 ml of each extractants were performed using a mechanical extractor. Bray-1 solution extracted the largest amounts of P, followed by deionized water and 0.01 M CaCl2. Bray-1 solution extracted 101.03 mg kg-1 of P from Consumo soil, 22.83 mg kg-1 from Soller soil and 12.35 mg kg-1 from Naranjito soil. Deionized water extracted 74.78 mg kg-1 of P from Consumo, 6.08 mg kg-1 from Soller soil and 4.24 mg kg-1 from Naranjito soil. The 0.01 M CaCl2 solution extracted 8.44 mg kg-1 of P from Consumo soil, 0.80 mg kg-1 from Soller soil and 0.49 mg kg-1 from Naranjito. The results indicate that the capacity of these soils to retain P has been saturated as a result of intensive manure applications. Proper management practices to decrease soil erosion and runoff should be implemented in the areas where these soils are located to prevent contamination of nearby soils and water resources. Resumen Cantidades excesivas de fósforo (P) en suelos agrícolas representa un riesgo de contaminación para las reservas de aguas superficiales y subterráneas. En suelos enmendados con gallinaza o estiércol de vaca pueden ocurrir pérdidas significativas de P por erosión o escorrentías. En adición al manejo y los factores ambientales, las propiedades químicas y físicas del suelo influyen en la pérdida de P. El contenido de P en tres suelos con un historial intensivo de aplicaciones con gallinaza y estiércol de vaca fue evaluado. Tres soluciones extractoras de P (agua deionizada, 0.01 M CaCl2, y la solución Bray-1) fueron evaluadas. Los suelos utilizados fueron Consumo (Fine, mixed, semiactive, isohyperthermic Typic Haplohumults) y Naranjito (Fine, mixed, semiactive, isohyperthermic Typic Haplohumults) enmendados con gallinaza y Soller (Clayey, mixed, active, isohyperthermic, shallow Typic Haprendolls) enmendado con estiércol de vaca. Seis extracciones secuenciales con 20 ml de cada solución extractora fueron realizadas usando un extractor mecánico. El tiempo de la extracción fue de 30 minutos. La solución Bray-1 extrajo la mayor cantidad de P, seguido por el agua deionizada y 0.01 M CaCl2. La solución Bray-1 extrajo 101.03 mg kg-1 de P del suelo Consumo, 22.83 mg kg-1 del suelo Soller y 12.35 mg kg-1 del suelo Naranjito. El agua deionizada extrajo 74.78 mg kg-1 of P del suelo Consumo, 6.08 mg kg-1 del suelo Soller y 4.24 mg kg-1 del suelo Naranjito. La solución 0.01 M CaCl2 extrajo 8.44 mg kg-1 de P del suelo Consumo, 0.80 mg kg-1 del suelo Soller y 0.49 mg kg-1 del suelo Naranjito. Los resultados indican que la capacidad de estos suelos para retener P ha sido saturada como resultado de aplicaciones intensivas de gallinaza y estiércol de vaca. Prácticas de manejo para reducir la erosión y las escorrentías deberían ser implementadas en las áreas donde estos suelos están localizados para prevenir la contaminación de suelos cercanos y reservas de agua. Introduction Dairy and beef cattle production are the first and fourth agricultural commodities in economic importance

in Puerto Rico, respectively, and generated $231.0 millions in 2002. A dairy cow produces 14.94 ton

year-1 of fresh manure, equivalent to 1.89 ton year-1 of dry manure. A beef steer produce 6.70 ton year-1

of fresh manure, equivalent to 0.77 ton year-1 of dry manure (Muñoz, 1992). Broilers production is the

14

second agricultural commodity in economic importance on the island. According to the Puerto Rico

Department of Agriculture, there are approximately 8.3 million broilers. This industry produced 135.0

millions pound of fresh chicken with a value of $100.0 millions in 1999-2002. It is estimated that 100

broilers can produce 2.62 ton year-1 of fresh manure and 0.65 ton year-1 of dry manure (Muñoz, 1992).

The manure produced by these agricultural commodities can cause serious contamination problems if it is

not managed properly.

The manure can be an excellent fertilizer by virtue of increasing soil organic matter content, improving

soil aggregate stability, porosity, and water infiltration and reducing erosion (Muñoz, M. A. 1992;

Kleinman and Sharpley. 2003). However, excessive applications of this material represent a risk for the

environment, especially for the water bodies where the accumulation of nitrogen and phosphorus can

cause eutrophication and shorten their useful life (Muñoz et al., 1990). Knowledge of the capacity of the

soil to adsorb P, and the chemical nature of such adsorption is important to determine potential

contamination problems as a result of excessive manure applications. The present laboratory study was

conducted to: 1) evaluate phosphorus content in three manure amended soils, using different

extractants; 2) evaluate the effectiveness of the extractants in sequential extractions; and 3) to correlate

phosphorus concentration with soil chemical properties.

Materials and Methods Three soils series were used in the study: Consumo (Fine, mixed, semiactive, isohyperthermic Typic

Haplohumults), Soller (Clayey, mixed, active, isohyperthermic, shallow Typic Haprendolls) and Naranjito

(Fine, mixed, semiactive, isohyperthermic Typic Haplohumults). The Consumo and Naranjito soils were

amended with chicken manure, whereas Soller was amended with cow manure. Soil samples were taken

from 0-10 cm depth. The sequential extractions of P were carried out using a mechanical extractor (Fig.

1). The extraction system is made up of three syringes. The top syringe contains the extractants, the

middle syringe contains the soil sample and the bottom syringe collects the filtrate. The extractants were

deionized water, 0.01 M CaCl2 and the Bray-1 solution (0.025 N HCl + 0.03 N NH4F). A 10 g sample of

each soil was placed in the middle syringe, which contained a filter of 1 g of inert pulp. The extractan

volume used in each sequential extraction was 20 ml. Four replications for each soil were used and six

sequential extractions were performed. The equipment was set up for thirty-minute extractions.

Extractable P in each filtrate was analyzed with a thermo espectronic genesys spectrophotometer at wave

length 882 nm using the ascorbic acid method.

Soil pH was read from a pH meter using 5 g of soil homogenized in 10 ml of deionized water. Soil

organic matter was determined by the Walkley and Black method. Cation exchange capacity (CEC) was

determined by the NH4Cl saturation method, followed by Kjeldhal distillation (Sparks et al., 1996). Soil

particle size was determined by the hydrometer method.

15

Figure. 1. Mechanical Extractor

Results and Discussion Chemical and physical properties of the soils are presented on table 1. The pH for Soller soil was 5.56,

whereas the natural pH for Soller soil is moderately alkaline (Soil Survey Mayagüez Area, 1975). The acid

pH observed in this study may be the result of intensive manure applications. The nitrification process

generates hydrogen ions, causing acidification (Tisdale and Nelson, 1985; O’Hallorans et. al., 1997). The

pH for Naranjito soil was 6.02 and for Consumo soil was 6.73. The natural pH of Consumo and Naranjito

soils are very strongly acid. Manure applications seem to have an opposite effect on these acid soils,

compared to the moderately alkaline Soller soil. Chicken manure applications increase the pH of these

soils probably due to Al+3 complexation by organic acid and phosphate ions. Soller soil showed the

highest organic matter content (OM) (6.97 %) and the highest CEC (34.82 cmolc kg-1). The organic

matter contributes significantly to CEC especially in highly weathered soil (Table 1). The content of iron

oxides was higher in Naranjito and Consumo soils. The Soller soils showed the higher content of

aluminum oxides (Table 2).

Table 1. Chemical and physical properties of the soils

Texture %

Soil series

Sand Silt Clay

pH (1:2)

O.M. (%)

CEC (cmolc kg-1)

Soller 36 21 43 5.56 6.97 34.82 Consumo 30 31 39 6.73 4.63 23.43 Naranjito 34 28 38 6.02 4.39 21.59

16

Table 2. Iron and aluminum oxide content of the soils Oxides (%)

DCB Oxalate

Soil Series

Al Fe Al Fe Soller 1.53 4.78 0.74 0.89

Consumo 0.94 5.75 0.32 1.28 Naranjito 1.09 6.53 0.23 1.51

The greatest amount of P was extracted from Consumo soil (Figs. 2, 3, 4). According to its mineralogy

and chemical properties this soil should adsorb more P than Soller soil. These results suggest that the P

retention capacity of Consumo soil has been saturated by intensive applications of chicken manure. The

Bray-1 P of Consumo soil (258.2 mg kg-1) was also higher than for Soller and Naranjito soils (Table 1).

Naranjito soil showed the lowest content of available P (28.4 mg kg-1). This soil also showed the lowest

desorption of P with the three extractants. The P extracted with 0.01 M CaCl2 which is more

representative of P in soil solution was also higher in Consumo soil. Bray-1 solution extracted the largest

amounts of P in all soils. This extractant extracts available P which includes P weakly adsorbed to soil

colloids and P in solution. The total P extracted in the six sequential extractions with 0.01 M CaCl2

represents only the 40 % of the P extracted with the traditional method of Bray-1 (Table 3).

0

2

4

6

8

10

12

14

16

18

20

22

24

26

0 1 2 3 4 5 6 7

Number of extractions

Ext

ract

able

P (m

g kg

-1)

H2O CaCl2 Bray - 1H2O CaCl2H2OH2O

Figure 2. Sequential extractions of P from Consumo soils

17

0

1

2

3

4

5

6

0 1 2 3 4 5 6

Number of extractions

Ext

ract

able

P (m

g kg

-1)

7

H2O CaCl2 Bray - 1H2O CaCl2

Figure 3. Sequential extractions of P from Soller soils

0

1

2

3

4

1 2 3 4 5 6

Number of extractions

Ext

ract

able

P (m

g kg

-1)

H2O CaCl2 Bray- 1H2O CaCl2

Figure 4. Sequential extractions of P from Naranjito soil

18

Table 3. Total P extracted after six sequential extractions Soil series Bray-1

(mg kg-1) Deionized water

(mg kg-1) CaCl2

(mg kg-1) Soller 22.83 6.08 0.80

Consumo 103.03 74.78 8.44 Naranjito 12.35 4.24 0.49

Deionized water extracted more P than 0.01 M CaCl2. These two P fractions are more representative of

the P that can be lost from soils under the impact of rainfall and soil erosion. Consumo soil also showed

higher amounts of desorbed P with these two extractants, which confirms that the adsorption capacity of

this soil has been saturated by intensive manure applications (Laboski and Lamb. 2004). The lower

amounts of P extracted from Soller and Naranjito soils are in agreement with the lower content of Bray-1

available P in these two soils (Table 4). The deionized water extracted more P from Consumo soil in the

first two extractions than the Bray-1 solution (Figure 2), which is a clear indication of the high P content

in this soil. Such a pattern of P desorption was not observed for Soller and Naranjito soils. After the

fourth extraction P concentration decreased thus indicating that the remaining P is adsorbed more

strongly to soil minerals. For Soller soil the amount of P extracted with deionized water remained

constant after the fourth extraction whereas for Naranjito a slight decrease was observed. The 0.01 M

CaCl2 solution extracted the lowest amounts of P from all soils. Consumo soil showed the highest

extracted P with the traditional methods of deionized water and 0.01 M CaCl2 (Table 4), while Naranjito

soil gave more extracted P with deionized water than Soller soil (Table 4).

Table 4. P extracted with traditional methods of deionized water and 0.01 M CaCl2

Soil series Bray-1

(mg kg-1) Deionized water

(mg kg-1) CaCl2

(mg kg-1) Soller 47.2 7.28 2.41

Consumo 258.2 58.2 8.12 Naranjito 28.4 12.77 1.24

Conclusion The results indicate that intensive applications of manure may increase soil extractable P to levels that

can cause serious contamination problems to nearby water resources. The sequential extractions

indicate the capacity of adsorption and desorption of P from these soils. These P extractable methods

can be used to identify farm sites where excessive amounts of P are a potential contamination problem.

Also, they can be used as a guide to establish proper management practices to minimize or eliminate this

environmental hazard.

19

Literature Cited Kleinman, P. J. A., and A. N. Sharpley. 2003. Effect of broadcast manure on runoff phosphorus concentrations over successive rainfall events. J. Environ. Qual. 32:1072-1081. Laboski, C. A.M. and Jonh A. Lamb. 2004. Impact of manure application on soil phosphorus sorption characteristics and subsequent water quality implications. J. Soil Science 164:140-148. Muñoz, M.A., O.Colberg and J.A. Dumas. 1990. Chicken manure as an organic fertilizer. J. Agric. Univ. P. R. 74(2):139 -144. Muñoz, M.A. 1992. Uso de la gallinaza como fertilizante. Foro Conversión y Uso de gallinaza en Puerto Rico. Estación Experimental Agrícola, Colegio de Ciencias Agrícolas, Recinto Universitario de Mayagüez. O’Hallorans,J.M., M.A. Muñoz and Colberg. 1993. Effect of chicken manure on chemical properties of a Mollisol and tomato production. J. Agric. Univ. P.R. 77(3-4): 181-191. Sotomayor, D., G. A. Martinez, R. S. Mylavarapu, O. Santana, and J. L. Guzmán. 2004. Phosphorus Soil Test for Enviromental Assessment in Subtropical Soils. Soil Sci. and Plant Analysis. 35: 1485-1503. Sparks, D. L., A. L. Page, P. A. Helmke, R. H. Loeppert, P. N. Soltanpour, M. A. Tabatabai, C. T. Johnston, and M. E. Summer. 1996. Methods of Soil Analysis, Part 3-Chemical Methods. Soil Science Society of America Inc. and American Society of Agronomy Inc., Madison, Wisconsin, USA. 1390 pp. Tisdale, S.L. and W.L. Nelson, 1985. Soil Fertility and Fertlizer. 4th. Ed. McMillan Publishing Co. Inc. New York.

20

Dairy compost application and its effect on growth of Zoysia turfgrass Axel O. Ramírez Madera and Elide Valencia

Department of Agronomy and Soils, University of Puerto Rico, Mayagüez, PR

Abstract In Puerto Rico, turfgrass demand for golf courses, parks and residential areas is increasing. In sod harvesting of turfgrasses, topsoil (organic matter) is removed and this results in slower regrowth of the in situ turfgrass. The dairy industry in Puerto Rico produces excessive amounts of dairy compost (2 million ton annum-1) the application of which can be used to replace organic matter, but little is known about its effects on establishment and regrowth of turfgrasses. The objective of this study was to evaluate the effect of four rates of dairy compost application [0 (Control), 10 (Low), 15 (Medium), and 20 (High) ton ha-1] on the growth and development of Zoysia spp. cvs. Manila and Meyer. The study was conducted at Finca Alzamora on an Ultisol, Consumo clay (fine, mixed, semiactive, isohyperthermic Typic Haplohumults). The experimental design was a randomized complete block (area was 20 x 13-m; 260m²) with four replicates each of cvs. Manila and Meyer. On August 27, 2004, grass plugs (20cm²) were planted, and on October 25, 2004, compost was incorporated. Turfgrass % spread was measured bi-weekly for 12-wks. There were differences in the % spread at 12-wks between the two cultivars. Average spread for Manila was 23.1, 28.8, 28.8, and 26.9% for the C, L, M, and H rates, respectively. Corresponding values for Meyer were 40, 36.3, 30, and 53.8%. Preliminary results indicate a positive response of the cvs. Manila and Meyer to an increase in diary compost applications. Sod harvest was on February 22, 2005. After harvesting the turfgrasses, the second application of compost was done March 1, 2005. The % spread was measured bi-weekly for 6-weeks. Average spread for the L, M, and H application rates were 36.3, 55, 46.3, and 55% for Manila and 33.8, 68.8, 63.8, and 85% for Meyer. Dairy compost can serve as a source of organic matter in turfgrass establishment, thus providing an environmental friendly use for this potential contaminant.

Resumen En Puerto Rico, la demanda de césped ha ido en constante crecimiento debido a sus usos en campos de golf, parques y residencias urbanas. Al cosechar el césped, gran parte de la capa superior del suelo (materia orgánica) es removida y esto resulta en un lento rebrote. La industria lechera en Puerto Rico produce cantidades excesivas de composta (desechos) de vaquería (2 millones de ton/año) que puede ser utilizada como materia orgánica, pero se conoce muy poco sobre los efectos en el establecimiento y rebrote del césped. El objetivo de este estudio fue evaluar el efecto de cuatro tasas de composta de vaquería [0 (Control), 10 (Bajo), 15 (Medio) y 20 (Alto) ton ha-1] en el crecimiento y desarrollo de los cultivares de Zoysia, Manila y Meyer. El estudio se llevó a cabo en la Finca Alzamora en un suelo Ultisol de la serie Consumo arcilloso (fino, mixto, semiactivo, isohipertérmico Típico Haplohumults). El diseño experimental se realizó en forma de bloques completamente aleatorios (área de 20mx13m; 260m2) con cuatro repeticiones de ambos cultivares Manila y Meyer. El 27 de agosto de 2004, se sembraron “plugs” de 20cm2 de césped y el 25 de octubre de 2004, la composta fue aplicada e incorporada. El porcentaje de cobertura fue medido cada dos semanas por un período de 12 semanas. Hubo diferencias en el porcentaje (%) del área de cobertura entre ambos cultivares al cabo de las 12 semanas. El promedio de cobertura para Manila fue de 23.2, 28.8, 28.8 y 26.9% para C, B, M y A, respectivamente. Los valores correspondientes para Meyer fueron de 40, 36.25, 30 y 53.75%. Resultados preliminares indican una respuesta positiva en ambos cultivares a un aumento en la aplicación de composta de vaquería. La cosecha del césped se realizó el 22 de febrero de 2005. Después de la cosecha, la segunda aplicación de composta fue el 1 de marzo de 2005. El porcentaje de cobertura fue medido cada dos semanas por 6 semanas. El promedio de cobertura para C, B, M y A fue de 36.3, 55, 46.4 y 55% para Manila y de 33.8, 68.8, 63.8 y 85% para Meyer. La composta de vaquería puede servir como fuente de materia orgánica y así disminuir la contaminación del medio ambiente a través de su uso en el establecimiento del césped.

21

Introduction Zoysiagrasses are warm season grasses native to China, Japan, and other parts of Southeast Asia. They

are sod forming perennial species that possess both stolons and rhizomes. There are three principal

species of Zoysia: Zoysia matrella, Zoysia japonica, and Zoysia tenuifolia. (Duble, R.L.) In this experiment

the species’ used are Meyer (an improved strain of Zoysia japonica) and Manila (Zoysia matrella). Meyer

is a dark green colored turfgrass which has medium texture, grows well in full sunlight, tolerates medium

shade, spreads rapidly, is the most cold tolerant, and ideal for converting fescue lawns. Meanwhile,

Manila is a light green colored turfgrass which has fine texture, grows in full sunlight, tolerates more

shade, has a slow rate of establishment, is less cold tolerant, and forms a finer and denser lawn.

In Puerto Rico, turfgrass demand increases each year due to its use in golf courses, parks, athletic fields

and residential urbanization. The local production is now 53,000 feet²/year. The dairy industry in Puerto

Rico generates 2 millions ton/year of dairy cattle wastes causing problems of management and

environmental pollution. In areas of the southeast US and Texas, dairy manure has been composted and

used for crop production. According to the Texas Agricultural Extension Service, compost is a partially

stabilized product of microbial decomposition of organic materials. Feedstocks are the materials used to

produce compost: mixed municipal wastes, biosolids, yard trimmings, food wastes and animal manures

(Roe, N. 1996). Studies have shown that up to 75 percent of the nitrogen (N), 60 percent of the

phosphorus (P2O5) and 80 percent of the potassium (K2O) equivalent fed to dairy cattle are excreted in

manure. These elements are essential plant nutrients required by all plants for normal growth and

production (McFarlan et al., 1997). There is limited information on application of dairy compost on

turfgrasses. The objective of this study was to evaluate the effect of the dairy compost application rates

[0 (Control), 10 (Low), 15 (Medium), and 20 (High) ton ha-1] in the growth and development of the

Zoysiagrass cultivars Manila and Meyer.

Materials and Methods This study was conducted at the Alzamora Farm, University of Puerto Rico, Mayagüez Campus. Land

preparation was initiated in August 2004. The soil type was an Ultisol, Consumo clay (fine, mixed,

semiactive, isohyperthermic Typic Haplohumults). Field size was 20-m x 13-m (260m²). The experimental

design was a randomized complete block with four replicates. Each experimental unit measured 1m x 6m

(6m²) with a 1-m alley way.

On August 27, 2004 grass plugs measuring 20cm² were planted. Compost was applied on October 25,

2004 by incorporating in the first 1.27-cm of the top soil (40-cm from the plug’s center). Total compost

applied consisted of 0,1, 1.5, and 2 kg for the Control, Low, Medium and High rates, respectively. Plants

were irrigated as needed (approximately two times per week). The establishment rate of the cvs. Manila

and Meyer was determined by observing % spread in a 1 m2 quadrant bi-weekly for 12 wks. At 12-wk

post-planting (February 22, 2005), sod growth was harvested by cutting at 1.27-cm below ground. Soil

samples (five samples at random in each plot) were taken after sod-harvest for analysis.

22

To assess regrowth of the sod, a second dairy compost application was made on March 1, 2005. The

application was broadcast over the remaining stolons and rhizomes fragments. At 2-wk intervals (for 6

wks), regrowth was determined by measuring % spread in a 0.25 m2 quadrant. Tissue subsamples were

taken at 6-wk regrowth to determine nutrient status.

Results and Discussion In the establishment phase (12-wks post-planting), average spread for cv. Manila was 23.1, 28.8, 28.8,

and 26.7% for the C, L, M, and H rates, respectively; for cv. Meyer it was 40, 36.3, 30, and 53.8% for

the C, L, M, and H rates, respectively. There were differences among cultivars. Meyer exhibited a faster

establishment rate than Manila. Compost application rate effects on spread of Manila were smaller than

for Meyer. After 6-wks regrowth (post sod-harvest), the average spread for Manila was 36.3, 55, 46.3,

and 55% for the C, L, M, and H rates, respectively (Figure. 1a). Corresponding values for Meyer were

33.75, 68.75, 63.75, and 85%. As seen in Figure 1b, Zoysia Meyer responded much more to the

application of 20 ton/ha (85% spread). Preliminary and final results indicate a positive response of the

cvs. Manila and Meyer to an increase in dairy compost application (Figure. 2a and 2b).

Figure 1a. Cover area for Manila

60

50

40 Control

0

10

20

30

0 1 2 3 4 5 6 7

Time (Weeks)

% Low

Medium

High

23

CCoonnttrrooll LLooww

HHiigghh MMeeddiiuumm

Figure 1b. Coverage Area for Meyer

90

Figure 2a. Manila

Figure 2a. Meyer

80

70

60Control

50% LowMedium40High

30

20

10

00 7 1 2 3 4 5 6

Time (Weeks)

24

ww

HHiigghh mm Increased application rat

Fig. 4, Meyer and Manila

at all dairy compost appl

2

1.8

1.6

1.4

1.2

% N 1

0.8

0.6

0.4

0.2

0Meyer C

%N 0.0932

MMeeddiiuu

e

ic

F

CCoonnttrrooll

s of compost also resulted in higher % N in

turfgrass tissue responded positively following

ation rates (L, M and H).

Meyer L Meyer M Meyer H Manila C Manila L M

0.0902 0.1805 0.2656 0.0914 0.0885 0

Samples igure 3. Percentage of N in soil and in applied

25

LLoo

soil samples (Fig. 3). As shown in

nutrient extraction (N absorption)

anila M Manila H Compost

.0908 0.1782 1.8526

compost

3

2.5

2% N Meyer

1.5Manila

1

0.5

0 10 15 200 Compost (ton/ha)

Figure 4. Percentage of N in plant tissue

Conclusions Dairy cattle compost is a good source of organic matter rich in nitrogen that can serve as fertilizer.

Application of dairy compost promotes turfgrass establishment. Results suggest that it is also effective for

the growth, regrowth and development of Zoysia spp. cvs. Manila and Meyer. The use of dairy compost

as an organic fertilizer reduces it accumulation in areas where it can constitute a contaminant.

Cited Literature Duble, R.L., Turfgrass Specialist, Texas Cooperative Extension, Zoysiagrass. McFarlan, Provin, Feagley 1997, Texas Agricultural Extension Service, Managing Crop Nutrients Through Soil, Manure and Effluent Testing, Bulletin L-5175, 6p. Producción de Composta, Dirección de Infraestructura, Coordinación de Áreas Verdes y Forestación, Planta de Composta de la UNAM. Tabla de Materiales Orgánicos. Roe, N. 1996, Texas Agricultural Extension Service, Using Composts in Commercial Vegetable and Fruit Operations, Bulletin L-5157, 4p.

26

Effect of shrimp residue supplementation on intake and digestibility of grass hay Jonathan González1, Paul Randel1, Abner Rodríguez1, Héctor Santiago1, and Elide Valencia2

1Department of Animal Science, University of Puerto Rico, Mayagüez Campus 2Department of Agronomy and Soils, University of Puerto Rico, Mayagüez Campus

Abstract Intakes of dry matter (TDMI), crude protein (CPI), and neutral-detergent fiber (NDFI), and digestibilities of dry mater (DMD), crude protein (CPD), and neutral-detergent fiber (NDFD) of tropical grass hay (TGH) supplemented with commercial goat feed (CGF) or shrimp residues (SR) were evaluated. The objective was to find a substitute for CGF in small ruminant diets. Nine adult rams of approximately 25 Kg were randomly assigned to nine metabolic cages. Feed was easily accessible for intake and water was offered ad libitum. The metabolic study consisted of three treatments: TGH with no supplementation, T1; TGH supplemented with CGF, T2: and TGH supplemented with SR, T3. The experimental design was a 3x3 latin square. In each period, dry matter and nutrient intake and digestibility were quantified using the total faeces recollection method. TDMI was highest in T2, but T1 and T3 were similar. DMD was similar in the three treatments. CPI was highest in T3, and similar in T1 and T2. CPD was similar in the three treatments. Both NDFI and NDFD were similar in the three diets. In summary, SR represents an alternative to substitute for CGF in small ruminant diets. Production costs should be evaluated as well as nutrient conversion efficiency of the by-product. Resúmen Se evaluó el consumo total de materia seca (CTMS), proteína bruta (PB) y fibra detergente neutro (FDN); y la digestibilidad de materia seca (DMS), proteína bruta (DPB) y fibra detergente neutro (DFDN) de heno de gramíneas tropicales (HGT) suplementadas con residuos de camarón (RC) o concentrado comercial (CC). El objetivo fue evaluar un sustituto nutricional al CC en dietas para rumiantes pequeños. Se utilizaron nueve corderos criollos adultos de aproximadamente 25 Kg distribuidos al azar en nueve jaulas metabólicas provistas de comederos y bebederos. El estudio metabólico consistió de tres tratamientos; HGT sin suplementación, T1; HGT suplementado con CC, T2; y HGT suplementado con RC, T3. El diseño experimental fue de cuadrado latino 3 x 3. En cada periodo, se cuantificó la cantidad de forraje consumido (FC) y DMS, DPB y DFDN utilizando la técnica de recolección total de heces. El CTMS fue mayor en T2, mientras T1 y T3 fueron similares. La DMS fue similar en los tres tratamientos. El CPB fue mayor en T3 que T1, y T2 fue similar a T1. La DPB fue similar en los tres tratamientos. El CFDN y DFDN fue similar en T1, T2 y T3. En resumen, el RC representa una alternativa nutricional para el CC en sistemas de producción de rumiantes pequeños. Se precisa evaluar los costos de producción y la eficiencia de conversión de nutrientes de este suplemento. Introduction

Since there is no local production of grains in Puerto Rico, concentrate ingredients used in small ruminant

diets are imported and expensive. Consequently, it is essential to find innovative substitutes for

commercial feed. Imported ingredients need to be substituted by more economical, easily available, and

nutritionally adequate constituents.

A local aquaculture enterprise produces nearly 1,800 tons of salt water shrimp. Since the head comprise

44% of the total body weight of raw shrimp (Meyers and Rutledge, 1971) an estimated 800 tons of

27

resulting waste is deposited in landfills for disposed. Shrimp meal (SM), is the dried waste obtained from

the shrimp industry. SM contains approximately 50% crude protein (CP) on a dry matter basis (Rosenfeld

et al., 1997) and could replace soybean as high-protein ingredient used in feed. SM has been tested in

broiler feeding at 6% of the diet with favourable results for carcass characteristics (Maldonado et al.

2004). The Objective of this study was to evaluate SM as a substitute for CGF in small ruminant diets.

Materials and methods

The dried and ground shrimp wastes were transferred from the Small Animal Research Farm in Lajas of

the Department of Animal Industry (Originally from the processing facilities of Eureka Marine Products in

Dorado) These has been dried using a 8’ x 8’ air steam drier at 65º C for 72 h, then grounded to pass a

1.0 mm screen). Chemical analysis of the dried waste showed approximately 41% crude protein.

Warm season grass hay was used as a basal element in diets formulated to meet or exceed NRC

recommendations for sheep. Two different supplements were used: SM, and commercial feed (14%CP).

SM was mixed with corn grain to obtain a mixture of this CP content.

Nine rams of similar body weight and age were confined in metabolic cages. Three groups of three rams

were selected randomly to receive the different diets: 100% hay (T1, control), 80% hay and 20%

commercial feed (T2); and 80% hay and 20% SM (T3). These diets were formulated according to NRC

recommendation for rams (NRC, 1994). Both diets including supplements were offered as a single meal.

Water was offered ad-libitum. Each experimental period consisted of a six-day adaptation phase and a 5-

day sampling phase. Diets were rotated at the end of each period.

Digestibility was determined using the total feces recollection method. Data were analyzed using the GLM

procedures of SAS© (SAS Institute, 1990), appropriate to a latin square design. The Tukey multiple

comparisons test was used to separate treatment means. All statements of significance are based on a

value of P<0.05.

Results

As shown in figure 1, total DM and CP intake was highest in T2. Rams supplemented with SR had similar

DM intake, but higher CP intake relative to the control animals. No difference in NDFI was observed in

this study. Digestibility of DM was higher in rams supplemented with commercial concentrate or shrimp

residues than in those without supplementation (figure 2). Animals eating shrimp residues also showed

higher crude protein digestibility than the control group, but lower than that of rams supplemented with

the commercial product. No effect of supplementation on NDF digestibility was observed.

28

Intake (g)

4000

2000

0 DMI CPI NDFI

2612.79b 74.56c 1976.1C 2873.02a 124.95a 2183.15CC 2463.34b 108.63b 2109.73SR

Figure 1. Intake of DM, CP, and NDF per treatment

Means with di erent superscripts dif er (P<.05) ff f

ff ff

(%)

80

60 40

20

0

DMD CPD

50.69b 49.32c 57.88C

56.05a 67.45a 58.02CC

55.43a 60.49b 56.82SR

NDFD

Figure 2. Digestibility of DM, CP, and NDF per treatment Means with di erent superscripts di er (P<.05)

29

Shrimp meal Rams used in experiment

Metabolic cages used for total feces recollection

Conclusion

The results of this study show that SR represents an alternative to substitute for CFC as a dietary nitrogen supplement in small ruminant diets. Literature Cited AOAC 1990. Official methods of analysis. 15th Ed. Association of Oficial Analytical Chemist. Arlington, VA. Maldonado L. and H. Santiago, 2004. The effects of using shrimp meal in broiler diets on life performance and carcass traits. Udergraduate research program, Livestock and Environment Group (1) p. 1-6. Meyers, S.P. and J.E. Rutledge, 1971. Shrimp meal, A new look at an old product. Feedstuffs 43 (49): 31. National Research Council (NRC), 1994. Nutrient requirements for small ruminants. Rev. 9 National Academy Press, Washington DC. Rosenfeld, D.J; et al. 1997. The effect of using different levels of shrimp meals in boiler diets. Poultry Sci. 76:581-587. SAS Institute, 1990. SAS/ STAT guide for personal computers. Version 6.12 version. SAS Institute Inc. Cary, NC.

30

The use of paper products as alternative litter materials on performance, carcass quality, and footpad lesions of broilers Kenneth H. Aponte, Héctor L. Santiago, and Abner A. Rodríguez

Department of Animal Industry, University of Puerto Rico at Mayagüez

Abstract A study was conducted to evaluate the utilization of recycled paper products as litter material on performance, carcass quality, and leg problems of broilers. A total of 168 broiler chicks were raised to market age (42d). Birds were assigned to 12 pens bedded with either rice hulls (RH - control), a 50:50 mix of shredded white paper and RH (SWP), or a 50:50 mix of shredded newspaper and RH (SNP) with four replicate pens per treatment. Traits measured were bodyweight (BW), feed intake (FI), feed conversion (FC), carcass yield (CY), breast blister score (BBS), footpad burn scores (FPBS), and mortality. Litter moisture percentage (LMP) was assessed at 14, 28, and 42 d of age. Litter material had no influence on BW, FI, BBS, and mortality. However, birds raised in SWP had numerically lower FI and higher BW when compared to those raised in RH and SNP litter. No significant differences in FC were observed among treatments from 7 to 28 d of age. At 35 and 42 d, birds raised in SWP litter had significantly lower FC than that of controls, whereas FC of birds raised in a SNP litter did not differ from the other treatments. No differences were found for CY among treatments. At all sampling times, LMP was significantly higher in SNP litter when compared to controls. No litter caking problems were observed in any of the treatments. Significant differences in FPBS were observed among all treatments. Birds raised in SNP litter had the highest scores, followed by SWP and RH litter. The results suggest that recycled paper products could be an excellent alternate bedding material for broilers. The use of SWP litter appears to improve broiler performance and reduce the incidence footpad problems.

Resumen Se realizó un experimento con el propósito de evaluar la utilidad de productos de papel reciclado como material alterno para camada de pollos parrilleros y sus efectos sobre el crecimiento, desempeño productivo y problemas de patas. Un total de 168 pollos parrilleros fueron criados hasta la edad de mercado (42d). Las aves se asignaron a 12 jaulas de piso con camada de cascarilla de arroz (CDA - Control), una mezcla 50:50 de CDA y papel blanco triturado (PBT) o una mezcla 50:50 de CDA y papel periódico triturado (PPT) con cuatro repeticiones por tratamiento. Se evaluó el peso corporal (PC), consumo de alimento (CA), conversión alimenticia (CAL), rendimiento de la canal (RC), laceraciones de la pechuga (LP), quemaduras del cojín de la patas (QCP) y la mortalidad. El porcentaje de humedad de la camada (PHC) se determinó a los 14, 28 y 42 d de edad. El material utilizado como camada no afectó el PC, CA, LP y mortalidad de las aves. Sin embargo, los pollos criados en PBT obtuvieron numéricamente un menor CA y un mayor PC al compararse con aquellos criados en CDA y PPT. No se observaron diferencias significativas en la CAL de los 7 a los 28 d de edad. A los 35 y 42 d, los pollos criados en PBT mostraron una mejor CAL que las aves criadas en CDA, mientras que la CAL de los pollos criados en PPT fue similar a los demás tratamientos. No se encontraron diferencias en el RC entre los tratamientos estudiados. En todos los periodos de muestreo, el PHC fue significativamente mayor en PPT al compararse con las demás camadas. No se observaron problemas de áreas húmedas en ninguna de las camadas estudiadas. Se observaron diferencias significativas en QCP, siendo la incidencia mayor en los pollos criados en PPT, menor en CDA e intermedia en aquellos criados en PBT. Los resultados sugieren que los productos de papel reciclado pueden ser un excelente material alterno de camada para el levante de pollos parrilleros. La utilización de PBT mejora el desempeño productivo y reduce la incidencia de QCP.

Introduction

As the broiler industry continues to grow traditional litter materials such as rice and coffee hulls become

scarce and costly causing a potential problem and concern. Thus, the need to search for alternative litter

materials is of great importance.

31

In Puerto Rico, 770,000 tons of paper and cardboard are generated per year making these products the

major waste materials of the island. These products are inexpensive and extremely available for

potentially benefit of the broiler industry. Previous studies have shown that recycled paper products can

be useful materials for bedding. Malone and Allen (1982) reported that broilers reared on shredded

newspaper litters had higher body weights at 28 and 49 d than those reared on sawdust. However, paper

litters had significantly higher moisture content and caking problems than those of sawdust litters.

Martinez and Gernat (1995) reported no effect of paper litter treatments on live performance of broilers.

In addition, litter moisture was similar for all treatments. Malone and Chaloupka (1983; 1992) reported

that the use of paper-based litters significantly improved body weight and feed efficiency when compared

to broilers grown on wood shavings or sawdust.

Therefore, recycled paper products appear to be a potential alternative source of litter material for the

local broiler industry. The use of these materials could be considered by the industry if there are no

adverse effects on production performance and carcass quality and if factors such as availability,

handling, and cost are proper. The objective of this study was to evaluate the effects of recycled paper

products as litter materials on growth performance, carcass quality, and leg problems of broilers.

Materials and Methods A total of 168 broiler chicks were raised under standard commercial conditions in an open-sided naturally

ventilated poultry house at the Agricultural Experiment Station Small Animal Research Farm in Lajas.

Birds were randomly assigned to 12 floor pens with four replicate pens per treatment. The concrete floor

pens were bedded with 2.5 inches of rice hulls (RH - Control), a 50:50 mix of RH and shredded white

paper (SWP) or a 50:50 mix of RH and shredded newspaper (SNP). Chicks were placed at a stocking

density of 1 ft2 in pens containing one bell feeder and nipple drinkers. Birds were raised under a 24 h of

light schedule and fed ad-libitum for the duration of the study.

A three phase feeding regime of a starter (0 to 14 d), grower (15 to 28 d), and finisher (29 to 42 d) was

used. Diets were corn and soybean-based and formulated to meet or exceed the NRC recommendation

for broilers (NRC, 1994). Feed intake (FI) and body weights (BW) were measured once a week. At the

end of each phase, 200 g of litter from each pen was sampled and litter moisture percentage (LMP)

assessed. Litter caking was monitored daily and if present measured and expressed as a percentage of

the total pen area.

At 42 d, a total of 60 birds were processed to determine carcass traits. Ten h prior to processing, 20

birds per treatment were randomly selected, wing banded, weighed, and placed in copes without access

to feed and water. Birds were processed according to standard commercial practices. Carcasses were

chilled for 5 h in an ice-slush tank after which they were weighed (CW) and carcass yield (CY) calculated

as percentage of live BW. The gizzard was weighed (GW) as an indicator of the consumption of litter

32

material. Data of breast blisters (BBS) and footpad burns (FPBS) were recorded assigning a score from 1

to 3 depending on the severity of the lesions.

Data were analyzed for statistical significance according to a Complete Randomized design by ANOVA

using the General Linear Model procedures of SAS ® (SAS Institute, 1990). The Tukey’s test option of

SAS® was used to compare and separate treatment means when significant by ANOVA. All statements of

significance are based on a probability of P ≤ 0.05.

Results and Discussion As shown in Table 1, litter treatments had no effect on BW of broilers at any age. However, from 7 – 35

d of age, there was a constant numerical difference between treatments. Birds reared on SWP had

numerically lower FI and higher BW when compared to those reared in RH and SNP. No significant

differences in FC were observed among treatments from 7 to 28 d of age. However, after 35 d birds

raised in SWP litter had significantly lower FC than controls, whereas FC of birds raised in a SNP litter did

not differ from the other treatments (Table 2). No differences in CW, CY, and GW were observed among

treatments (Table 2). Gizzard weight was used as an indicator of litter consumption as it has been shown

to be correlated with intake of litter. The lack of differences in gizzard size suggests that consumption of

litter was equal for all treatments.

At all sampling times, LMP was significantly higher in SNP litter when compared to RH, whereas LMP of

SWP had values similar to RH and SNP at 14 and 42 d, respectively (Table 3). It is important to

emphasize that no litter caking problems were observed throughout the study in any of the treatments.

As shown in Table 2, significant differences in footpad burn score (FPBS) were observed among all

treatments. Birds raised in SNP litter had higher scores, followed by SWP and RH litter. The incidence of

FPBS can be related to the differences observed in LMP. The higher the LMP the higher the FPBS scores

observed. Higher levels of LMP are associated with an increase in ammonia production which in turn

increases the likelihood of lesions in the footpad. Likewise, although no differences among treatments

were observed for BBS, the tendency was toward a concomitant increase in these lesions with increase

litter moisture. Nevertheless, the incidence of BBS and FPBS reported in the present study was low.

Lesions were small and no severe cases of breast blisters or footpad burns were observed.

Conclusion The results of this study indicate that recycled paper products could be a potential alternate litter material

for broilers. Broilers raised in these products showed similar or superior performance relative to those

reared in traditional RH litters. The use of SWP litter appears to improve broiler performance and reduce

the incidence footpad problems. These products should be considered by the industry because of their

low cost, abundance, absorbent properties, and positive effects on performance.

33

Table 1. The effect of litter material on live performance traits of broilers

Litter Treatment Age (d)

RH SWP SNP SEM Probability

Individual body weight (g) 7 115.2 132.3 123.7 4.94 0.10 14 297.5 332.7 323.8 9.53 0.07 21 631.6 b 679.6 a 633.7 ab 11.69 0.03 28 1,085.2 1,153.5 1,116.8 21.76 0.14 35 1,499.3 1,569.5 1,550.8 33.78 0.35 42 1,996.5 2,075.2 1,989.5 37.13 0.25

Accumulative Feed Intake (g) 7 122.98 126.47 130.59 11.76 0.90 14 463.73 479.82 498.65 31.25 0.74 21 1,188.37 1,079.27 1,117.68 67.86 0.54 28 2,198.8 1,951.1 2,075.3 124.53 0.41 35 3,448.4 3,020.9 3,096.6 140.96 0.13 42 4,146.2 3,656.8 3,766.0 177.30 0.18

Feed conversion (g feed / g BW) 7 1.07 0.96 1.06 0.10 0.69 14 1.56 1.45 1.54 0.09 0.62 21 1.88 1.59 1.76 0.10 0.17 28 2.03 1.69 1.86 0.11 0.16 35 2.30 a 1.92 b 2.01 ab 0.09 0.04 42 2.07 a 1.76 b 1.90 ab 0.07 0.03

Table 2. The effect of litter treatments on processing yields, breast blisters, footpad burn and mortality of broilers

Litter Treatment Trait RH SWP SNP

SEM Probability

Dressed weight (g) 1520 1560 1493 44.7 0.57 Dressed yield (%) 66.8 67.3 66.2 0.48 0.28 Gizzard weight (g) 49.9 47.0 46.3 2.3 0.51 Breast blister score 0.25 0.37 0.50 0.16 0.53 Footpad burn score 0.05 c 0.60 b 1.3 a 0.14 <0.0001

Mortality (%) 5.35 3.57 5.35 3.44 0.91

Table 3. Moisture percentage of litter treatments

Litter Treatment Age (d) RH SWP SNP

SEM Probability

% 14 18.5 b 19.37 b 21.37 a 0.29 0.0002 28 21.32 b 28.83 ab 34.85 a 2.45 0.0115 42 16.75 b 19.25 a 21.00 a 0.56 0.0016

34

Experimental Birds

Footpads burns observations Literature Cited Malone, G.W. and G.W. Chaloupka. 1983. Influence of litter type and size on broiler performance. Poultry Science 62:1741-1746.

Malone, G.W. and P.H. Allen. 1982. Recycled paper products as broiler litter. Poultry Science 61: 2161-2165.

Malone, G.W. and G.W. Chaloupka. 1992. Evaluation of shredded newspaper litter materials under various broiler management programs. Poultry Sci. 61:1385.(Abstr.)

Martinez,D.F. and A.G. Gernat. 1995. The effect of chopped computer and bond paper mixed with wood shavings as litter materials on broiler performance. Poultry Science 74: 1395-1399.

National Research Council (NRC). 1994. Nutrient Requirements of Poultry. 9th rev. ed.

SAS Institute, 1990. SAS® / STAT guide for personal computers. Version 6.12 edition. SAS Institute Inc. Cary, NC.

35

Quality and aerobic stability of silage made of hay hydrated with crude milk or

antibiotic milk Edna Betancourt, Angel A. Custodio and Abner A. Rodríguez

Department of Animal Industry, University of Puerto Rico, Mayagüez

Abstract In Puerto Rico more than one million quarts of raw milk are rejected annually and dumped in the waste lagoons of dairy farms, which contributes to pollution and constitutes a loss of unutilized nutrients. More than 50% of this milk is discarded because it is tainted with antibiotics. The objectives of the current study were: 1) to determine the best proportion of milk and hay to produce silage and 2) to determine if it is possible to obtain good quality silage using milk containing antibiotics. The study was divided into three trials. The first trial, to determine the best proportion of crude milk (M) and hay (H) to produce silage, included four treatments: 1) 30M:70H w/w, 2) 40M:60H w/w, 3) 50M:50H w/w, and 4) 60M:40H w/w ensiled in micro-silos of PVC pipes in triplicates. The silos were opened after 21 days. In the second trial two different antibiotics, used to treat cows with mastitis, were added to samples of M and used to hydrate H (50M:50H). An extract of the hydrated H was cultured in Rogosa medium to determine if antibiotic inhibit the growth of Lactobacillus. The third trial consisted of three treatments: 1) 50H:50M w/w, 2) 50H:50 w/w of antibiotic-milk diluted in 80 volumes of crude M, and 3) 50H:50 w/w with antibiotic-milk diluted in 20 volumes of crude milk. The silos were opened after 14 days. Criteria used to compare the treatments included pH, fermentation products, and aerobic stability for five days after silo opening. An analysis of variance was performed on the quality data with days and treatments as independent variables. The model for aerobic stability data included treatments, hours of exposure and their interaction as independent variables. In the first trial the best silage was obtained with 50M:50H. In the second trial the cultured extract showed ample growth of Lactobacillus, demonstrating inhibition. In the third trial the pH at silo opening was almost equal (P>.05) for the three treatments (4.42 to 4.47) showing an equally good fermentation. Upon exposure to air for 120 hours pH increased more (P< .01) in treatment with no antibiotic (5.16) than treatments with low and high levels of antibiotic, 4.56 and 4.41, respectively. Temperature increased to a peak of 34.0 ºC, 30.7 ºC and 29.3 ºC for none, low and high level of antibiotic, respectively. These results reveal that equal proportion of H and raw M produce good silage and that it is possible to obtain an adequate fermentation and stable silage using M containing antibiotic. Resumen En Puerto Rico más de un millón de cuartillos de leche cruda son decomisados anualmente y depositados en las charcas de almacenamiento de desechos de las vaquerías. Poco más del 50 % de esta leche es descartada por estar contaminada con antibiótico. Los objetivos este estudio fueron: 1) determinar la mejor proporción de leche y heno para ensilar y 2) determinar si es posible preparar un buen ensilaje hidratando heno (H) con leche (L) contaminada con antibiótico. El estudio se dividió en tres pruebas. La prueba primera, para determinar la mejor proporción de L y H, consistió de cuatro tratamientos: 1) 30L:70H w/w, 2) 40L:60H w/w, 3) 50L:50H w/w y 4) 60L:40H w/w, ensilados en micro-silos de PVC en triplicados. Los silos se abrieron a los 21 días de fermentación. En la prueba segunda, dos de los antibióticos utilizados comúnmente para tratar mastitis en vacas lecheras, se añadieron a distintas muestras de leche, se preparó la mezcla para ensilar y se cultivó un extracto de esta mezcla en medio Rogosa para determinar si se inhibe el crecimiento de Lactobacillus por la presencia de antibiótico. La prueba tercera consistió de tres tratamientos: 1) 50H:50L w/w, 2) 50H:50 L con antibiótico diluida en 80 volúmenes de leche cruda, y 3) 50H:50 w/w L con antibiótico diluida en 20 volúmenes de leche cruda. Los silos se abrieron después de 14 días. Los criterios para comparar los tratamientos incluyeron pH, productos de fermentación y estabilidad aeróbica por cinco días después de abiertos los silos. El modelo del análisis de varianza para las variables dependientes asociadas a la calidad del ensilaje incluyó a días y tratamientos como variables independientes. El modelo para la estabilidad aeróbica incluyó a tratamientos, horas de exposición y sus interacciones, como variables independientes. En la primera prueba el mejor ensilaje se obtuvo con la mezcla 50L:50H. En la segunda prueba hubo mucho

36

crecimiento de Lactobacillus, lo que demuestra que el antibiótico tuvo poco efecto inhibidor. En la tercera prueba el pH al momento de abrir los silos fue casi igual (P< .05) para los tres tratamientos (4.42 a 4.47), demostrando una buena fermentación. Después de la exposición al aire por 120 horas hubo mayor incremento en pH (P< .05) en el tratamiento sin antibiótico (5.16) que en los tratamientos de bajo y alto nivel de antibiótico, 4.56 y 4.41, respectivamente. La temperatura incrementó hasta un pico de 34.0ºC, 30.7ºC y 29.3ºC para cero antibiótico, nivel bajo y nivel alto de antibiótico, respectivamente. Los resultados revelan que con una proporción igual de leche y heno se obtiene un buen ensilaje y que es posible obtener una fermentación adecuada y ensilaje estable usando leche con antibiótico.

Introduction In Puerto Rico the milk that does not fulfill the minimum standards set for human consumption is

discarded. In 2003-2004 a total of 1,653,914 quarts of raw milk were rejected (ORIL, 2004). Of this

total, 896,536 quarts were rejected because of antibiotic content. This milk is discarded in waste lagoons

of dairy farms where it may leak and pollute underground water (Weinberg et al., 2003). There is a

growing concern in our society for the sustainability of agricultural activities, urging the development and

implementation of technology that reduces the negative impact of agricultural activities on the

environment. The alternatives to reduce these negative effects include recycling and reutilization. Using

rejected milk as feed for animals instead of dumping it in waste lagoons may be a way of both, increasing

the level of sustainability of milk production and avoiding the loss of the nutrients present in the rejected

milk (fat, protein, sugars and minerals). There are several problems associated with milk utilization for

feeding animals: milk deteriorates fast if not kept refrigerated, an expensive procedure; milk discarded

because of antibiotic content cannot be used to feed lactating cows or other animals producing foods for

human consumption in short periods of time. Enforcing agencies require that rejected milk be dumped

immediately to assure that it does not end up being used for human consumption.

Hay is an important feed that is present on almost every dairy farm. Previous research has demonstrated

that hay can be hydrated with milk to make silage. Weinberg et al. (2003), in Israel, successfully

prepared silage for animal feeding made of milk, straw and other returned dairy products. Crespo, et al.

(2004), of the University of Puerto Rico, Mayaguez Campus, successfully prepared silage made of rice

hulls hydrated with milk. Silage production may be an inexpensive way of storing the nutrients present in

rejected milk to be used in the feeding of dry cows and growing heifers.

The process of silage production depends on the growth of bacteria that produce lactic acid, a process

that may be impaired if the milk used to hydrate the hay is contaminated with antibiotics. Usually, the

level of antibiotics in milk is low due to the dilution of the milk from the treated cow with that of the rest

of the milking cows of the herd. It is not known if Lactobacillus can grow well and produce good silage

from hay hydrated with milk containing low levels antibiotics. The present study has two purposes: 1) to

determine the best proportion of milk and hay to produce silage and 2) to determine if it is possible to

obtain good quality silage using milk contaminated with antibiotics. If we can make good silage with hay

and milk, even if it contains antibiotic, the Office for the Regulation of the Dairy Industry of Puerto Rico

37

(ORIL) would have the option of dying the milk with a non-toxic dye, to avoid the possibility of its

utilization for human consumption, and allowing it to be ensiled rather than dumped in waste lagoons, a

more friendly alternative for the environment.

Materials and Methods

The study was conducted in the Animal Nutrition Laboratory of the University of Puerto Rico at

Mayagüez. It consisted of three trials:

First trial

The purpose was to find the best proportion of raw milk and hay to prepare silage. It consisted on four

treatments: 1) 30M:70H w/w 2) 40M:60H w/w 3) 50M:50H w/w 4) 60M:40H w/w. Milk was added to hay

and mixed thoroughly until no milk accumulated in the bottom of the container. The mixtures were

ensiled in micro-silos of PVC pipe in triplicate. Samples were taken from the original mixed material the

day the silo was closed and from the silage at silo opening after 21 days of fermentation. The samples

were analyzed for chemical composition, organic acids and pH. A sample of 500 g drawn from each silo

were put into plastics bags immediately after silo opening and exposed to aerobic conditions (Figure 9)

for the next five days. Variables measured were temperature, pH and chemical composition at days 0, 1,

3 and 5 of aerobic exposure.

Second trial

The purpose was to determine if Lactobacillus bacteria present in hay at the moment of hydration grow

in vitro in the presence of milk containing antibiotic. Two commercial antibiotics commonly used to treat

and prevent mastitis in dairy farms were tested: Today® (Cephapirin sodium) and Biodry® (Novobiocin

sodium). Today® is used to treat milking cows with clinical mastitis and has a 96 hour withholding period.

Biodry® is specially formulated to be used right after the last milking of the lactation (at dry off) and

requires that the cow not be milked again for at least 30 days after treatment. Both antibiotics were

tested at two levels. The low and high levels consisted of adding the equivalent of .1 and .5 ml of

antibiotic, respectively, to a gallon of milk. Six treatments were prepared in triplicate by mixing equal

weights of hay with: 1) water (control), 2) raw milk (control), 3) milk with low level of Biodry®, 4) milk

with high level of Biodry®, 5) milk with low level of Today® and 6) milk with high level of Today®.

Immediately after mixing, 50g of each mixture were added to 450 ml of distilled water and mixed

thoroughly by means of a Stomacher. Samples were drawn from the liquid part of each mixture, diluted

in series up to10-10 and cultured in Rogosa medium. After 48 hours the cultures were counted.

Third trial

This trial was to observe if good quality silage can be obtained by mixing hay with milk containing

antibiotic. To obtain milk contaminated with antibiotic, one cow was treated in two quarters of the udder

38

with the antibiotic Today®. Ten hours later that cow was milked and the milk diluted with crude milk to

mimic the dilution that takes place when the milk of a cow treated with antibiotic is deposited in the milk

tank. Two levels of dilution were tested: one volume of milk from the treated cow in 80 volumes of crude

milk (1/80) and one volume of milk from the treated cow in 20 volumes of crude milk (1/20). Three

treatments were compared: 1) 50H:50M (control with crude milk) w/w, 2) 50H:50M 1/80 w/w, 3)

50H:50M 1/20 w/w. Treatments were ensiled in triplicate in micro-silos of PVC pipe and opened after 14

days of fermentation. To evaluate the quality of the silage, pH and organic acids were measured on days

0 and 14. Also, after silo opening, 500g of the fermented material from each silo were exposed to

aerobic conditions for five days to test its aerobic stability.

Microsilos Silos Opening

Results and Discussion

First trial

Chemical analyses of the silages with different proportions of hay and milk, opened at 21 days of

fermentation, are in Table 1. The pH decreased (P< .01) and lactic acid content increased (P< .01) as

the proportion of milk increased, showing a better fermentation when the proportion of milk reached

50% or higher.

The changes in pH (Figure 1) and temperature (Figure 2) upon aerobic exposure show better stability for

the silage with 50% of milk than for the silage with 60% of milk.

These results and the fact that is easer to make a mixture with 50% of milk, led us to select this

proportion for the second and third trials.

39

Table 1. Comparison of silages obtained from different proportions of raw milk and hay

Treatments

Milk : Hay

pH

Lactic acid

g/100 g

Acetic acid

g/100 g

Butiric acid

g/100 g

30:70 5.20 .568 .333 0

40:60 4.52 .514 .279 0

50:50 4.25 .621 .176 .008

60:40 3.94 1.028 .392 .006

3.5

4

4.5

5

5.5

6

0 24 72 120HOURS OF EXPOSURE

pH

Treatment 1 Treatment 2Treatment 3 Treatment 4

Figure 1. Change in pH over 120 hours of aerobic exposure in first trial

202224262830323436

0 6 12 18 24 30 36 42 48 60 72 84 96 108

120

HOURS OF EXPOSURE

TEM

P (C

º)

Treatment 1 Treatment 2Treatment 3 Treatment 4

Figure 2. Change in temperature over 120 hours aerobic exposure in first trial

40

Second trial

Lactobacillus grew well in all the plates with low serial dilutions of both Today® and Biodry®, even at the

1/20 dilutions. The number of colonies decreased to a level that could be counted when the serial

dilutions reached 10-4. Further dilutions showed that, as expected, Biodry® (Figure 3) inhibited the

growth of Lactobacillus more than Today® (Figure 4). The results of this trial (in which the level of

antibiotic was higher than expected in milk rejected from dairy farms) suggest that it will be possible to

make silage with milk contaminated with the antibiotics Biodry® and Today®.

Silage samples exposed to aerobic conditions

Petri plates with Rogosa SLmedium for Lactobacillus culture

41

0

500

1000

1500

2000

-4 -5 -6 -7

DilutionsN

umbe

r of c

ultu

res

.5 Antibiotico .1 Antibiotico

Figure 3. Colonies of Lactobacillus in silage mixture containing the antibiotic Biodry®

0

500

1000

1500

2000

-4 -5 -6 -7Dilutions

Num

ber o

f cul

ture

s

.5 antibiotico .1 antibiotico

Figure 4. Colonies of Lactobacillus in silage mixture containing the antibiotic Today®

Third trial

Chemical analyses of the silages with and without antibiotics after 14 days of fermentation are in Table 2.

The differences in pH between treatments with antibiotic and the control were not significant (P> .05). A

significant difference (P< .05) was observed for lactic acid in favour of the control. Both, the pH and the

lactic acid levels show that a good fermentation was achieved by hydrating hay with milk obtained from a

cow treated with antibiotic.

After aerobic exposure, the pH (Figure 5) and temperature (Figure 6) increased moderately in all

treatments up to 72 hours. Thereafter, pH level and temperature of the silages with antibiotic increased

less than the control, demonstrating greater stability under aerobic conditions.

42

Table 2. The effect of milk containing two levels of antibiotic on silage quality

Treatments 1 pH Lactic acid

g/100 g

Acetic acid

g/100 g

Butiric acid

g/100 g

Control 4.42 1.493 .186 .008

1/80 dilution 4.44 1.325 .283 .007

1/20 dilution 4.47 1.122 .149 .009 1 Control is raw milk, 1/80 and 1/20 is milk from a cow treated with antibiotic diluted in 80 or 20 volumes of raw milk

4.34.44.54.64.74.84.9

55.15.2

0 20 40 60 80 100 120 140HOURS OF EXPOSURE

pH

Control 1/80 dilution 1/20 dilution

Figure 5. Change in pH after 120 hours of aerobic exposure in third trial

26272829303132333435

0 20 40 60 80 100 120

HOURS OF EXPOSURE

TEM

P (C

º)

Control 1/80 dilution 1/20 dilution

Figure 6. Change in temperature after 120 hours aerobic exposure in third trial

43

Conclusions

The proportions of 50% hay and 50% crude milk result in a mixture easy to make, that produces good

fermentation and shows no significant deterioration after 5 days of aerobic exposure. It is possible to

obtain a good fermentation and stable silage with hay hydrated with milk contaminated with antibiotic.

Literature Cited

Crespo, M., A. Custodio and A. Rodríguez, 2004. Fermentation and aerobic stability of silages made of rice hulls hydrated with milk. Proceedings: Undergraduate Research Program, Livestock and Environmental Group. Department of Animal Science, University of Puerto Rico, Mayagüez Campus. Oficina de la Reglamentación de la Industria Lechera (ORIL). 2004. Informe Annual 2003-2004. Wienberg Z.G., Ashbell G., Chen Y. (2003). S abilization or returned dairy products by ensiling with straw and molasses for animal feeding. J. Dairy Sci. 86:1325-1329.

t

44

Fermentation characteristics and aerobic stability of mango (Mangifera indica) and starfruit (Avherroa carambola) residues

Neddie Cruz Maldonado, Suzika Pagán Riestra, and Abner A. Rodríguez Carías Department of Animal Industry, University of Puerto Rico, Mayagüez Campus

Abstract Fermentation characteristics and aerobic stability of mango (Mangifera indica, MS) and starfruit (Avherroa carambola, SS) silages were evaluated. Fermentation of fruit residues was done in micro-silos (1.2 kg) for 0, 30 and 112 days. Triplicate samples from each fermentation residue were analyzed for chemical composition, fermentation end-products, pH, and microbial populations [coliforms, (C); lactic acid producing bacteria, (LAPB); and molds and yeast; (MY)]. Aerobic stability was determined by changes in pH and temperature during 7 days of aerobic exposure. Initial chemical composition of MS and SS was different. After 30 and 112 days of fermentation pH was higher in SS than MS (P<0.05). Lactic acid bacteria population was higher in SS than MS (P<0.05), but coliforms population remained similar in both silages. Yeast and molds population was lower in fermented residues than fruit before ensiling. Lactic acid was the principal fermentation end product associated with the fermentation of MS and SS. Fresh MS and SS were more unstable to aerobic conditions than the fermented residues. In conclusion, higher levels of lactic acid and lower pH in fermented than fresh fruit residues, and higher stability to anaerobic conditions showed than silage production represents an alternative for the disposal of fruit residues. Further evaluation on the nutrition value of the silage is needed. Resumen Se evaluó las características fermentativas y la estabilidad aeróbica de ensilaje de residuos de mangó (Mangifera indica, EM) y carambola (Avherroa carambola, EC). La fermentación de los residuos de frutas se realizó en micro-silos (1.2 kg) por un periodo de 0, 30 y 112 días. Muestras triplicadas de cada residuo fermentado fueron analizadas para composición química, productos de fermentación, pH y poblaciones microbianas [coliformes, (C); bacterias productoras de ácido láctico, (BPAL); y hongos y levaduras; (HL)]. La estabilidad aeróbica fue determinada por cambios en pH y temperatura durante 7 días de exposición aeróbica. La composición química inicial de EM y EC fue diferente. Después de 30 y 112 días de fermentación el pH fue mayor en EC que en EM (P < 0.05). La población de BPAL fue mayor en EC que EM (P < 0.05), pero las poblaciones de coliformes fueron similares en ambos residuos de frutas. La población de hongos y levaduras fue menor en los residuos fermentados que en los frescos. El ácido láctico fue el mayor producto asociado con la fermentación de EM y EC. El EM y EC fresco resultaron ser más inestable a condiciones aeróbicas que los residuos fermentados. En resumen, el mayor contenido de ácido láctico y menor pH de los residuos fermentados comparados con los frescos y la mayor estabilidad de aquellos a condiciones aeróbicas demuestran que la elaboración de ensilaje representa una alternativa para el desecho de residuos de frutas. Se precisa una evaluación más extensa del valor nutricional del ensilaje.

Introduction

In Puerto Rico, fruits such as mango (MS) and starfruit (CS) that do not meet minimum standards for

human consumption or are produced in excess are rejected annually on farms throughout the island.

These fruits are disposed of in landfills, a practice that represents a source of environmental pollution and

increased costs of waste management. Considerable amounts of nutrients are thus lost, while limited

animal feed resources is an evident problem. These, considerations justify evaluating alternatives for the

disposal of fruit residues. Anaerobic fermentation of by-products is an option, for preserving feeds that

are seasonally abundant for later use during periods of feed shortage such as dry seasons (Chedlyl and

45

Lee, 2004). In previous studies with orange (Ci us sinensis) and pineapple (Ananas comosus) residues,

favorable results in the preparation of silage were obtained (Bosques, 2004; Pagán, 2004). However,

limited information regarding the elaboration of mango and carambola silage is available.

tr

Objectives

Determine the microbial succession, pH and fermentation characteristics of mango and starfruit residues.

Determine the aerobic stability of mango and starfruit silages.

Materials and Methods

This research was conducted in the Animal Nutrition Laboratory, University of Puerto Rico, Mayagüez

Campus. Fruit residues were obtained from the Alzamora Farm located at the same Campus, and from

the Tropical Agricultural Research Station in Isabela. For the fermentation process, fruits were sliced and

compacted in PVC lab micro-silos (1.2 kg), where they were allowed to ferment during 30 and 112 days

(Figure 1). Triplicate samples for each period of fermentation were analyzed for chemical composition

(MS, OM, IM, and CP, AOAC, 1990; cell wall components, Van Soest et al., 1991: water soluble

carbohydrates, WSC, Dubois, 1956) and fermentation end-products (at the commercial laboratory, Dairy

One Forage Lab, Ithaca, NY).

For microbial populations associated with the fermentation process, 50 g of fresh and fermented material,

in triplicate, were homogenized with a sterile buffer solution of potassium phosphate. Serial dilutions (10-

1–10-8) from homogenized solutions were poured on Petri plates with selective media for coliforms (Violet

Red Agar), lactic acid bacteria (Rogosa SL Agar) and yeasts and molds (Rose Bengal Agar supplemented

with chloranphenicol). Microbial populations were manually enumerated after 48 h of incubation using a

digital counter.

To determine the aerobic stability of fresh and fermented residues, triplicate samples (1 kg) of each

sample (fresh and after 30 and 112 d of fermentation) were placed in styrofoam containers lined with

plastic and exposed to air during 7 days. During this period, temperature was registered every 6 hours

the first 24 hours and every 12 hours for the next 6 days. Measurement of pH was done at days 0, 1, 3,

5 and 7 of air exposure.

Fermentation characteristics data were analyzed as a completely randomized design with a 2 (fruit

residues) x 3 (fermentation periods; 0, 30 and 112 d) factorial arrangement of treatments. Aerobic

stability data were analyzed as a completely randomized design with a factorial arrangement 2 (fruit

residues) * 7 (days of aerobic exposure). Bonferroni t-test was used for means separations.

46

Fresh Fruit Residues

Anaerobic Fermentation (30 and 112 days)

Final product

Figure 1. Fermentation process of fruit residues

47

Results and Discussion Fermentation Characteristics

Initial chemical composition of starfruit and mango residues was different (Table 1). Initial pH, organic

matter, NDF, hemicellulose, and WSC content were lower in starfruit than in mango residues, but crude

protein was higher. Based on the initial carbohydrate content, both residues showed an optimum sugar

content for fermentation.

Table 1. Initial Chemical composition and pH of starfruit (A. carambola) and mango (M. indica)

Item1 Starfruit Mango

Dry Matter 16.96 22.67

Organic Matter2 86.99 97.77

Inorganic Matter2 13.01 2.23

Crude protein2 5.16 0.91

NDF2 24.92 32.65

ADF2 5.91 5.91

Hemicelulose2 19.01 26.74

Water soluble CHO’s 3.75 10.38

pH 4.53 5.09

1 Means of triplicate samples

2 DMB

In both fruit residues minimum amounts of coliforms were detected during the fermentation period, lactic

acid bacterial populations remained similar, and yeast and molds populations decreases as a result of the

fermentation process (Table2, 3).

Table 2. Microbial populations in starfruit after 0, 30 and 112 of fermentation

Microbial group Fermentation Period (days)

ufc / 50 g CS 0 30 112

COL ND 1.84a 0b

LAPB 4.31 4.13 4.56

YM 7.49a 3.87b 3.23b

a,b Means in the same row with different letters differ (P < 0.05) Not detected

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Table 3. Microbial populations in mango after 0, 30 and 112 days fermentation

Microbial Group Fermentation Period (days)

ufc / 50 g MS 0 30 112

COL 5.32a 0b 0b

LAPB 4.57a 3.96a ND

YM 4.80a 1.57b 3.5ab

a,b Means in the same row with different letters differ (P < 0.05)

Lactic acid was the principal fermentation end-product associated with the ensiling of mango and starfruit

residues. However, a higher lactic acid production was observed in starfruit than in mango. In both

fermented fruit residues low levels of acetic acid were detected regardless of fermentation periods, and

propionic and butyric acids were not detected (Table 4, 5). In both fermented residues and at both

lengths of fermentation final pH was lower in starfruit and mango silages than the fresh residues.

Table 4. Fermentation end-products and pH of starfruit after 0, 30 and 112 days of fermentation

Fermentation endproducts (%) Fermentation Period (days)

0 30 112

Lactic Acid 0.12b 0.28a 0.39a

Acetic Acid 0.41a 0.16b 0.15b

Propionic Acid ND ND ND

Butiric Acid ND ND ND

pH 4.53a 3.64b 3.67b

a,b Means in the same row with different letters differ (P < 0.05)

Table 5. Fermentation end-products and pH of mango after 0, 30 and 112 days fermentation periods

Fermentation endproducts (%) Fermentation Period (days)

0 30 112

Lactic Acid 0.46b 0.81a 0.64a

Acetic Acid 0.26b 0.35b 1.6a

Propionic Acid ND ND ND

Butiric Acid ND ND ND

pH 5.09a 3.32b 3.53b

a,b Means in the same row with different letters differ (P < 0.05)

49

Aerobic Stability

In both fresh of fermented fruit residues pH remained similar regardless of length of fermentation and

days of aerobic exposure. Similar results were reported in citrus silages as pH did not increase in

fermented orange residues during 7 days of aerobic exposure (Bosques, 2004). These results may

indicate that pH is not a good indicator of aerobic deterioration of fermented fruit residues. Aerobic

instability of fermented mango residues was visually observed in this experiment (Figure 2). However it

seems other organic acids present in fruits (i.e. malic acid) are poorly utilized by the microflora associated

with the aerobic instability of the fermented or materials.

Table 6. pH of fresh and fermented starfruit exposed to aerobic conditions during 7 days

Aerobic Exposure (days)

Fermentation Period (days) 0 1 3 5 7

0 4.53 3.93 3.72 4.03 4.10

30 3.64 4.18 4.33 5.24 5.36

112 3.67 3.69 4.33 4.62 6.11

Table 7. pH of fresh and fermented mango exposed to aerobic conditions during 7 days

Aerobic Exposition (days)

Fermentation Period (days) 0 1 3 5 7

0 5.09a 4.93a 3.71b 3.77b 3.9b

30 3.32 3.48 3.43 3.44 3.54

112 3.55 3.67 3.63 3.66 3.76 a,b Means in the same row with different letters differ (P < 0.05)

Figure 2. Instability of mango residues during 7 days of aerobic exposure

50

A greater increased in temperature was observed in fresh than in fermented starfruit residues after 7

days of aerobic exposure (figure 3). This result indicates a greater aerobic stability of the fermented than

of the fresh residue. Furthermore, starfruit ensiled during 112 days was more stable to aerobic conditions

than the residue ensiled during 30 days. Similar results were observed in mango residues exposed to

aerobic conditions (figure 4). Mango wastes fermented during 112 d were more stable than fresh

residues or fruit residues fermented during 30 days as evidenced by lower temperature during the

aerobic exposure period.

29

30

3130.04a

°C

22

23

24

25

26

27

28

Figure 3. Changes in temperature of star

35

30

25

20 °C

Figure 4. Changes in temperature of man

0

5

10

15

0 20 40 60 80 100 12

Aerobic Exposition (ho

030112

26.6b

25.33c

fruit exposed to aerobic conditions during 7 days.

030

go exposed to aerobic conditions during 7 days

112

0 140 160 180

urs)

Atmosphere

51

Conclusions

Silage preparation represents an alternative for the disposal of fruit residues. Fermented residues were

more stable to aerobic conditions than the fresh fruits and a greater aerobic stability was observed in fruit

residues fermented during 112 days in comparison with 30 days.

Literature Cited

AOAC.1991.Official Methods of Analysis.15th Ed. Association of Official Analytical Chemist. Arlington, VA. Bosques, J., A. Rodriguez, D. Cianzio. Fermentation characteristics and aerobic stability of orange pulp silage treated with urea. Livestock and Environment Group. Year 1, Vol.1, 2004. Chedly, K., S. Lee. Silage from by-products for smallholders. Institut National Agronomique de Tunisie.Retrieved in 2004 from http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGP/ Pagán, S., A.A. Rodríguez, y E. Valencia. 2004. Características fermentativas y poblaciones microbianas de ensilaje de residuos orgánicos de china (Citrus sinensis) y piña (Ananas comosus). Memorias Reunión Científica Anual SOPCA. pp 55. Van Soest, P.J., J.B. Robertson , B.A. Lewis, 1991. Methods for dietary fiber, neutral detergent fiber, and non-starch polyssacharides in relation to animal nutrition. J. Dairy Sci. 74: 3583-3597

52

Fermentation of milk waste solids from a milk processing plant for potential use in animal feed

Sully M. Morales, Teodoro Ruiz, Héctor L. Díaz Department of Animal Industry, University of Puerto Rico, Mayagüez, PR

Abstract Milk Water Solids (MWS) are byproducts of milk processing plants in the manufacture of cheese. MWS are treated and then disposed of at an extra cost to the milk industry. MWS are unstable in aerobic environments, showing signs of rapid decomposition. The purpose of the present study was to determine the value of MWS as animal feed and to determine if molasses can be added as a method of preserving fresh MWS. The experiment evaluated five treatments consisting of a mixture of MWS and molasses at the following percentages: T1) 0% (Control), T2) 5%, T3) 10%, T4) 20%, and T5) 30%, ensiled in micro-silos and replicated five times. Silage quality was tested 21 days after ensiling. MWS silages were analyzed for pH values, odor, Dry Matter (DM), Crude Protein (CP), and Organic Matter contents (OM), In Vitro Degradability (IVD) and aerobic stability (AS). Results indicated that increasing the concentration of molasses resulted in increased IVD (21-61%) and reduced pH. Treatment did not affect AS of the silage in a consistent manner, perhaps because there is little fermentation of MWS, as indicated by the low In Situ Degradability (20-30%)of the MWS. However, T1 did exhibit an offensive odor, which was eliminated with the addition of >10% molasses. Ensiling with molasses increased the stability and degradability of the MWS. Further experiments are needed to determine the feasibility of using MWS in animal feed.

Resumen El Lodo Proveniente de Aguas Residuales (LPAR) es un subproducto de la producción de queso en plantas procesadoras de leche. El LPAR es procesado y luego desechado a un costo adicional a la industria lechera. El LPAR es inestable en ambientes aeróbicos, se descompone rápidamente cuando es expuesto al aire. El propósito del presente estudio fue determinar el valor de LPAR como alimento para animales y determinar sí el ensilaje de melaza y LPAR es una manera efectiva de preservar LPAR fresco. Se evaluó cinco tratamientos que consistían de una mezcla de LPAR y melaza a los siguientes porcentajes: T1) 0% (Control), T2) 5%, T3) 10%, T4) 20%, T5) 30%, que fueron ensilados en micro-silos con cinco repeticiones. La calidad de los ensilajes fue estudiada después de 21 días de fermentación. Los ensilajes de LPAR fueron analizados para pH, olor, contenidos de Materia Seca (MS), Proteína Cruda (PC), Materia Orgánica (MO), Degradabilidad In Vitro (DIV) y Estabilidad Aeróbica (EA). Los resultados indican que al aumentar la concentración de melaza, la DIV aumenta (21-61%) y el pH disminuye. El tratamiento con melaza no afectó la EA del ensilaje de una manera consistente, talvez porque hubo poca fermentación del LPAR, así demostrado por la poca Degradabilidad In Situ (20-30%) de este. El T1 exhibió un olor ofensivo, el cual fue eliminado al añadir >10% de melaza. El ensilar con melaza aumenta la estabilidad y la degradabilidad del LPAR. Es preciso experimentos futuros para determinar la factibilidad de usar LPAR en la alimentación de animales.

Introduction

Milk Water Solids (MWS) is a byproduct of the manufacture of cheese and includes water used to clean

the pipe systems of milk processing plants. The resulting liquid is treated with inoculants to aid in

fermentation. A cationic flocculant is then added for the coagulation of solid particles in the liquid to

produce sludge. Excess water is removed from the sludge by means of compression, resulting in MWS.

The MWS are then transported to a solid waste management facility at an extra cost to the milk

processing plant. MWS occupy space at a facility where space is at a premium and contributes to

exacerbate the problem of waste management in Puerto Rico. WWS are unstable in aerobic

53

environments, demonstrating signs of decomposition such as foul odor. The signs of decomposition can

be perceived as soon as 3 to 4 hours after exposure to air, thus MWS must be stabilized before use.

The milk processing plant INDULAC produces 730,000 gallons of MWS per year and disposes of this

material at a cost of $45,000 annually (INDULAC, 2004). The extra cost of disposal affects the net

income of the operation. However, MWS have the potential to be used as a source of protein and

minerals in animal diets (T. May, 1991, R. Belyea, 1990), but this potential has not yet been exploited.

May (1991) successfully replaced 33% of soybean meal with MWS in a medium-quality hay diet for dairy

heifers. The soybean meal and MWS were used as sources of protein. Belyea (1990) successfully used

MWS in animal feed as a mineral supplement. Thus, feeding diets containing MWS is an alternative

means of disposal of a product that could potentially benefit not only the processing plant, but also the

livestock producer (R. Belyea, 1990).

Objectives

Determine the minimum amount of molasses that can be added to MWS to obtain silage of good quality,

as a method of preserving the nutrient in fresh MWS.

Determine the value of MWS as animal feed

Materials and Methods

This study was conducted in the Animal Nutrition Laboratory at the University of Puerto Rico, Mayagüez

Campus. Milk Waste Solids (MWS) were obtained from the milk processing plant INDULAC (San Juan,

PR). Samples were taken from the MWS storage tank and placed in sealed plastic containers. These

containers were immediately stored in a portable cooler stocked with ice for transportation. The samples

were later frozen to prevent decomposition. Samples of MWS were dried at 65ºC for 48 hours and

analyzed for Amino Acid Profile (AAP) at Dairy One Laboratories (Ithaca, NY). Sample size used for AAP

was 30g. MWS were also analyzed for Dry Matter (DM) content and In Situ Degradability (ISD). Sample

size used for testing DM content was 1,000g and samples were dried at 65ºC for 48 hours in a

convection oven. Two canulated heifers consuming the same diet of grass hay were used for the ISD

experiment. Sample size for ISD was 1.0g DM; samples were analyzed after 72, 24, 18, 12, 6, 3, and 0

hours of exposure to artificial intraruminal conditions.

MWS and molasses were ensiled in 1-liter plastic laboratory silos for 21 days. The experiment was

performed with five treatments of five repetitions each. Treatments were mixtures of MWS and molasses

at 0% (T1), 5% (T2), 10% (T3), 20% (T4) and 30% (T5). Silage quality was tested 21 days after

ensiling.

MWS silages were evaluated for odor, aerobic stability (AS), crude protein (CP), organic matter (OM)

content, pH, and In Vitro Degradability (IVD) to determine silage quality. DM was determined by drying a

200g sample at 65ºC for 168 hours in a convection oven. AS was determined by exposing a 500g sample

54

in a Styrofoam container. Samples were tested for AS by determining their temperature at 0, 6, 12, 24,

48, 72, 96, 120, 144, and 168 hours of aerobic exposure.

CP was determined by the micro-Kheldahl method using a 0.150 g sample. Ash content was determined

by incinerating a 1.0g dry sample at 600ºC for 8 hours. For a DIV determination, 0.25g samples were

subjected for 24 hours into a Daisy* ANKOM artificial rumen digester. Ruminal liquid used for the IVD

experiment was taken from a dairy heifer on a grass pasture forage diet. The results obtained from these

experiments were analyzed with a general linear model of the statistical analysis program SAS (1990), by

means of a variation analysis of variance (ANOVA) and the TUKEY test for media separation of means.

Fermentation of milk waste solids

Results and Discussion

Chemical composition of the by-product indicated that methionine, cystine, and lysine were found in low

concentrations compared to the other amino acids present (Table 1). Calcium and Phosphorus are the

most abundant minerals found in MWS and the by-product is a valuable source of crude protein (Table

2). During the fermentation process pH values decreased as the percentage of molasses in the silage

increased (Figure 1). There were significant differences in pH values between silages with different levels

of molasses. Silages with less than 10% molasses had very low acid contents. Silages with more than

10% molasses had high lactic acid, compared to other acids present. Silages with 20% molasses had the

highest lactic acid levels.

55

Table 1. Amino Acid Profile of MWS

Amino Acid Percentage

Aspartic acid 2.50

Glutamic acid 3.29 Serine 1.29 Glycine 1.24 Histidine 0.53 Arginine 2.22

Threonine 1.59 Alanine 2.85 Proline 1.02

Tyrosine 0.74 Valine 1.57

Methionine 0.15 Cystine 0.26

Isoleucine 2.43 Leucine 2.80

Phenylalanine 0.83 Lysine 0.83

01234567

pH

0% 5% 10% 20% 30%Molasses

Figure 1. pH values of silages after 21 days of fermentation

56

Table 2. Chemical analysis of MWS as report by a commercial laboratory

Components (%) As Sampled Basis

Dry Matter Basis

Moisture 8.8 0 Dry Matter 91.2 100 Crude Protein 46.1 50.5 Adjusted crude Protein 46.1 50.5 Soluble Protein ND 13 Degradable Protein ND 32 Crude Fat 1.8 1.9 Ash 10.68 11.70 TDN 75 82 NEL, (Mcal/lb) 0.79 0.87 NEM, (Mcal/lb) 0.84 0.92 NEG, (Mcal/lb) 0.57 0.62 Calcium 2.76 3.02 Phosphorus 2.38 2.61 Magnesium 0.17 0.19 Potassium 0.36 0.39 Sodium 0.29 0.32 PPM Iron 378 414 PPM Zinc 44 48 PPM Copper 6 6 PPM Magnesium 6 7 PPM Molybdenum 2.2 2.4 Sulfur 0.30 0.31(Mcal/lb) Chloride Ion 0.12 0.13

Table 3. Organic Acids Profile of silages after 21 days of fermentation

Lactic

PPM

Acetic

PPM

Propionic PPM

Ios-butyric PPM

Butyric

PPM

T1 10 182 108 19 18

T2 31 510 262 78 671

T3 1966 461 60 9 493

T4 3260 405 11 6 37

T5 2388 998 9 0 0

DM content increased as the percentage of molasses added to the MWS increased. Silages did not show

significant differences in OM content between treatments, thus the addition of molasses has little affects

in this regard. Crude protein content decreased markedly as the percentage of molasses increased. The

MWS showed a low DIS percentage ranging from 20 to 30%. The degradability of the product increased

57

up to a certain point with the addition of molasses. Mixtures containing more than 20% molasses showed

no significant further increase in degradability of the MWS.

Table 4. Dry Matter, organic Matter (OM), and Crude Protein (CP) contents of silages after 21 days of fermentation

T1 T2 T3 T4 T5

DM 17.11 18.20 21.56 28.27 34.06

OM 84.39 85.36 86.02 85.45 83.77

CP 49.40 46.00 40.13 28.25 22.52

10

20

30

40

50

60

Deg

rada

bilit

y

0% 10% 30%Molasses

Figure 7. Influence of Molasses on In Vitro Degradability of MWS after 24 hours

Total DegradabilityMWS Degradability

There were no significant differences between silage temperatures upon aerobic exposure (Figure 2),

thus the addition of molasses to MWS had little effect on its aerobic stability according to this criterion.

The low temperatures of the silages reflect the low degradability of the MWS (20 to 30%. IVD).

58

70

75

80

85

90

95

100Te

mpe

ratu

re ºF

24 48 120Hours

Figure 2. Aerobic Stability temperatures of silages after 21 days of fermentation

T1T2T3T4T5

Conclusion MWS are a valuable source of Calcium, Phosphorus and Crude Protein. Molasses addition did not affect

AS of the silage in a consistent manner as indicated by temperature, perhaps because there is little

fermentation of MWS, as indicated by the low In Situ Degradability (20-30%). The control silage

exhibited an offensive odor, which was eliminated with the addition of >10% molasses, indicating that

the addition of molasses increased the level of stability and preservation even with little fermentation.

The low degradability of the MWS silages indicates that they have a low solubility and digestibility in the

rumen, which could possibly be beneficial due to rumen by-pass of the high CP content MWS. The low

ISD values could be an indication of a high level of rumen undegradeable protein (RUP), and not of low

total digestibility of the MWS. Thus, further experiments are needed to determine the feasibility of using

MWS in animal feed.

Literature Cited Belyea, R.L., et al., (1990). Evaluation of Dairy Wastewater Solids as a Feed Ingredient. J. Dairy Sci. 1990. 73:1864-1871 May, T, et al., (1991). Evaluation of Dai y Food Processing Wash Water Solids as a Protein Source: III. Nitrogen Utilization by Heifers Fed Medium-Concen ate Diets. J. Anim. Sci. 1991. 69: 3425-3434

rtr

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Acknowledgements

Poultry Facilities, Department of Animal Science, Faculty of Agricultural Sciences, Lajas, P.R.Dairy Farm, Department of Animal Science, Faculty of Agricultural Sciences, Lajas, P.R.Small Ruminant Program, Department of Animal Industry, University of Puerto Rico, Mayagüez, P.R.

Undergraduate Research included in this proceedings was supported byUSDA- CSREES - HSI Education Grant Programs

We would like to express our thanks to the following who provide products or services in support of research summarized in this report

Gratefulness is also expressed to the following research technicians, graduate students, and staff from the Animal Industry Department

Agro. Héctor Díaz RíosAgro. Rebeka Sanabria LeónAgro. Suzika Pagán RiestraMrs. Jacqueline RiveraMr. Miguel Rivera

Participating Faculty Area of Expertise

Dr. Elide Valencia Chin Dra. Miguel MuñozPlant – Animal Relationship Soil Science(Elideval@uprm.edu) (@mmunoz@uprm.edu)

Dr. Angel A. Custodio González Dr. Paul F. Randel FoldingAnimal Breeding – Dairy Cattle Animal Nutrition (acustod@uprm.edu) (p_randel@rumac.uprm.edu)

Teodoro M. Ruiz López Dr. Héctor Santiago AnadónDairy Cattle Management/Nutrition Poultry Production/Meat Quality(teodoro_ruiz@cca.uprm.edu) (hsantiago@uprm.edu)

Dr. Abner A. Rodríguez CaríasAnimal Nutrition – Organic Wastes Management(abner@uprm.edu)

Department of Animal Industry P.O. Box 9030

University of Puerto Rico, Mayagüez CampusMayagüez, P.R. 00680

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