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Subclinical mastitis in small ruminants: prevalence, comparative aspects and prevention
, LeitnerDr. Gabriel National Mastitis Reference Center,Kimron Veterinary Institute, Israel
Dr. Nissim SilanikoveDepartment of Animal Physiology,
Agricultural Research Organization,The Volcani Center, Israel
Welfare
Is subclinical mastitis of concern to the small ruminant industry?
Zoonosis agents* brucellosis* tuberculosis
Milk quantity?Yield of milk, fat, total proteins,
casein and curd
Milk quality?Internal bacterial contamination,
somatic cell count, secreted enzymes
Economic question
Subclinical mammary infectionis an economical question
In most herds most of the time the proportion of infected animals
is unknown
Cost benefit
* Cost of identification
* Loss of yield, quality
* Cost of treatment
Cost benefit
* Cost of identificationHerd individual
Bulk SCC BacteriologySCC, CMT
Bacteriology ‐
Laboratory costSCC – No routine measurement CMT – Low cost; animal place
Parturition Drying off
CMTSCC (x 1000)Bacterial status
0-150- 300Uninfected2-4> 500Infected
Cells in
milk
High infection periodTesting periods
* Loss of yield, quality
Aim: to calculate the loss of milk and cheese as related to the level of subclinical udder infection in a herd.
To clarify the major factors that influence milk yield and, consequently, curd yield in Assaf sheep and Saanen and Shami × Anglo-Nubian goats.
Sheep
1217812760,00025243415251,300,00050365123382,100,00075
Goat
162138640,000253241615920,0005048628231,300,00075
HerdHalf-udder model
Herd Half-udder model
Total curd loss (%) Milk loss (%)ProjectedSCC
Infection rate
Leitner
G.
et
al.
(2008).
Estimate
of
milk
and
curd
yield
loss
of
sheep
and
goats
with intrammamary
infection
and
its
relation
to
somatic
cell
count.
Small
Ruminant
Res., 74:221‐225
Animal model built on glandular level
One udder-half infected with CNSspecies and the contra-lateral beingfree of bacteria
+ -
S. capraeS. chromogenesS. epidermidisS. simulansS. xylosos
Sheep and goats were considered infected onlyif the same bacteria was isolated and SCCwas high (> 106) in three consecutive samples
Most udder-halves infected with CNS had a normal morphology, similar to the contra-lateraluninfected gland
Number of udder infectionBacteria
Sheep Goat 8 45S. aureus
78 28S. chromogenes277 171S. epidermidis68 97S. simulans21 36S. xylosus- 77S. caprae31 8Streptococci10 15Coliforms29 12Corynebacteria spp.
522 (33%) 489 (35.9%)Total infected
29 12Total uninfected
* Milk yield was measured separately for each udder-half
* Milk tested for: bacteriology, SCC, protein, fat, lactose
* Skim milk was analyzed for: casein, whey protein, albumin, proteose-peptone, and activities of Plasmin, Plasminogen activator and Plasminogen, ionized calcium(Ca2+) and calcium activity (aCa2+)
* Curd yield and Rennet clotting time
00.20.40.60.8
11.21.41.61.8
2
Uninfected Infected
SheepGoatKg
/ day
Milk yield (half) of sheep or goat infectedwith CNS species in one gland
and the contra-lateral being free
Sheep: - 0.81 Kg/dayGoat: - 0.58 Kg/day
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
Uninfected Infected
SheepGoatSC
C SCC (half) of sheep or goat infected
with CNS species in one gland and the contra-lateral being free
Sheep: + 2,088,000Goat: + 1,333,000
Parameter Sheep Goats
Uninfected Infected Uninfected Infected
Fat (g/L) 64.9±0.26 61.7±0.21 38.9±1.1 38.8±1.2
Protein (g/L) 58.5±0.07 53.5±0.10 34.2±0.5 35.0±0.5
Casein (g/L) 45.9±1.36 40.5±1.59 28.1±0.7 28.2±0.8
Lactose (g/L) 44.7±0.08 33.5±0.16 47.0±1.0 41.7±1.3
Whey (g/L) 11.9±0.38 12.8±0.16 6.1±0.3 6.8±0.4
Albumin (µg/mL) 517±31 759±59 280±22 472±50
Mean and SE of fat, protein, lactose, whey, casein and albumin in uninfected vs. infected
glands of sheep and goats.
0
0.5
1
1.5
2
2.5
Uninfected Infected
SheepGoatp -
p , g
/ LProteose-peptone concentration
Sheep + 247%, P < 0.0001Goat + 151%, P < 0.0001
Rennet clotting time of goat and sheep milk from uninfected vs. infected udder-halves
Goat Sheep0
50
100
150
200
250
300
350
400
450
500
Ti
me
(sec
)
Uninfected Infected
Curd yield of goat and sheep milk fromuninfected vs. infected udder-halves
0
5
10
15
20
25
30
35
SheepGoat
Uninfected Infected
C
urd
yiel
d (g
/L)
NO Infection Infection
Cost benefit
* Cost of treatment
Parturition Drying off
Cells in
milk
Testing periodsTreatment
Treatment is a choice:* Bactria sensitivity* Medicine exist* Cost benefit
Aim: determine dry-off treatment inAssaf sheep:
efficacy and a management tool forimproving milk quantity and quality.
Results
Sheep
%Number47.5%151/318Total infected halves
88.7134Total CNS17.223S. chromogenes50.067S. epidermidis3.04S. haemolyticus17.924S. simulans3.04S. xylosus8.912Unidentified CNS
IsolationsBacteria
Distribution of intramammary bacterialfindings in 159 dairy sheep (318 halves) at drying-off.
Results
Sheep
Distribution and [2] results of 159 dairy sheep udders (318 halves) before draying-off and 21-28 days post-partum, according to udder
bacterial infection.
Bacteria
P (2)NoYesBacteria
65 (71%)27 (29%)92YesTreatment
< 0.00018 (8%)54 (92%)59YesControl
57 (81%)13 (19%)70NoTreatment
NS70 (72%)27 (28%)97NoControl
After treatmentBefore treatmentGroup
Results
Sheep
Average milk yield, bulk-milk somatic cell count and percentage infection in the sheep flock in the course of the 2-yr study.
2 0 0 3 2 0 0 4 2 0 0 53 8 0
4 0 0
4 2 0
4 4 0
4 6 0
4 8 0
5 0 0
Y e a r
Ave
rage
milk
yie
ld (s
heep
lact
atio
n-1)
2 0
2 5
3 0
3 5
4 0
4 5
5 0
5 5Flock infection (%
)
Bulk tank som
atic cell count (x 1000)
8 0 0
1 0 0 0
1 2 0 0
1 4 0 0
1 6 0 0
1 8 0 0
2 0 0 0
2 2 0 0
2 4 0 0
2 6 0 0
- Average milk yield,
- somatic cell count,
- percentage intramammary infection.
Results
SheepMilk yields of uninfected and infected ewes.
0 2 5 5 0 7 5 1 0 0 1 2 5 1 5 0 1 7 5 2 0 0 2 2 50 .0
0 .5
1 .0
1 .5
2 .0
2 .5
3 .0
Milk
(L d
ay-1)
D a y s in m ilk
- uninfected,
- infected.
Cost benefit
Cost of identificationTime of sampling ‐
second week in lactation
and/or before drying off.
Test
‐
CMT and/or SCC and bacteriology
Improved milk yield quantity and quality of products
Cost benefit
Loss of yield, quality Milk Yield –
reduction of 5‐30%
Product quantity and quality
‐
reduction of 5‐30%
Reduction dependent on bacteria spices and animal’s breed
Cost benefit
Cost of treatment Recovery – 50‐85%
Existing Medicine –
availability and price
Recovery
depends on bacteria species and length of the infection
Prevention
Identification
Subclinical mastitis
Existing medicine, availability and price
Calculate cost benefit
Thanks