Management of the rumen: the main aspect of future

performance

Ing. Dana Kumprechtová, PhD.

University of Veterinary and Pharmaceutical Sciences Brno, Czech Republic

CONTENTS

• Digestive tract of ruminants

• Rumen microflora

• Main processes in the rumen

• RUMEN MANAGEMENT

• HEAT STRESS

COWpolygastric animal

COWpolygastric animal

Digestive tract of ruminants

• perfectly adapted to the utilization of plant origin foodstuffs, rich in cellulose• symbiotic microflora: digestion of cellulose, hemicellulose, non-protein nitrogen

Ruminant nutrition

host animal

Feed ruminal microflora

Main goal of dairy cow nutrition:

ensure

OPTIMUM CONDITIONS FOR

RUMEN FERMENTATION

RUMEN

• 150 l digesta

• natural fermentation tank and feed reservoir

• microorganisms adhere to feed particles and mucosal papillae

Ruminal motorics

• 2 – 3 contractions/minute

• contact of bacteria with the substrate

• stability of the rumen environment

• large particles are regurgitated

• rumination: 8 – 13 hours/day mechanical desintegration of feed buffering effect of saliva

• eructation (30 – 50 l gas/hour)

Ruminal microflora

BACTERIA

• 107 – 1012/ ml rumen fluid• cellulolytic bacteria

• bacteria producing VFA and lactic acid

• methane producing bacteria

• proteolytic bacteria

• lipolytic bacteria

Ruminal microflora

PROTOZOA

• 105/ml rumen fluid () 106/ml (concentrates)

• utilize readily soluble sugars and polysaccharides

• ? cellulose

• utilize starch – prevent a decrease in pH stabilize rumen fermentation

Ruminal microflora

FUNGI

• high celullolytic and hemicellulolytic activity

Main processes in the rumen

SACCHARIDES VFA

CRUDE MICROBIAL

PROTEIN PROTEIN

Energy nutrition of cattle

• 70 % VFA of bacterial origin

• 20 % microbial mass

• 10 % feed nutrients that escaped microbial fermentation

Volatile Fatty AcidsLactating cow – 3.5 kg/day

• acetate 55-75 % - from structural saccharides• propionate 15-20 % - from starch, sugar, pectines• butyrate 10 % - - from structural saccharides, sugar• valerate, isovalerate... 5%• lactate – readily converted to propionate

Volatile Fatty Acids

ACETATE fatty acids milk fat

PROPIONATE glucose lactose

BUTYRATE milk fat

ketone bodies

Crude Protein

DEGRADABLE microbial protein

NH3 ruminal wall

blood saliva rumen

NON-DEGRADABLE small intestine amino acids

Nitrogen metabolism

Factors affecting ruminal fermentation

Temperature

• microorganisms require stable temperature for the growth

• heat stress: temperature in the rumen

Water

• 80 – 90 % rumen contents

• VFA resorption in the rumen

• rumen motorics and turnover

• access to drinkers for all the cows

Ruminal motorics

Structural fibre (optimum particle size 4 – 5 cm)

• regurgitation

• motoric stimulation

• digesta mixing

• fermentation

Ruminal motorics

Impaired motorics: RUMEN TYMPANY

ACIDOSIS

Causes:

• high levels of non-structural saccharides in feed

• not enough structural fibre

• high doses of concentrate given separately from roughage

Fermentation products

Lactic acid: pH

ACIDOSIS

• ruminal mucosa ulceration

• liver damage

• lameness

• mastitis

Fermentation products

Ammonia:

too high levels of soluble protein in feed

high NH3 levels

RUMEN ALCALOSIS (pH > 7)

Rumen management

Rumen management

Optimum pH: 6.2 – 6.8

• buffering effect of saliva (bicarbonate): - structural fibre (60% cows in the herd ruminate 2 hours post feeding) - TMR – more even saliva production - alfalfa hay

• feeding several times a day

• optimum ratio roughage : concentrate

Rumen management

• dry matter intake

• pH in the rumen

• rumen degradable protein + readily fermentable sugars

• no changes in the diet

• selection of diet components by cows

Rumen management

Feed components• alfalfa hay• cotton seed

Feed supplements:Buffers:• sodium bicarbonate• magnesium oxide

Direct-fed microbials (probiotics)• lactic acid bacteria• yeasts – Saccharomyces cerevisiae• fungi – Aspergillus oryzae

Saccharomyces cerevisiaeEffects:

stability of the rumen environment

fermentation

VFA production

lactate production

utilization of ammonia

microbial protein synthesis

Saccharomyces cerevisiae

dry matter intake

milk production

mastitis occurrence

SCC

growth

acidosis

Milk production kg/head/day

30

32

34

36

38

40

42

44

46

week

mil

k p

rod

ucti

on

(kg

)

s.cervisiae

kontrola

Heat stress

Heat stress

THERMAL COMFORT ZONE IN CATTLE:

5 - 25 °C

Heat stress

• Increased respiration, heart rate (especially in high-producing and older cows)

• Increased metabolism

• Activation of sweat glands

• Increased body temperature

• Decreased physical activity

Heat stress

• Increased water requirement

• Decreased feed intake

• Decreased performance

• Lower percentage of milk protein and fat

Milk composition

N Milk yieldkg.l-1

Fat%

Protein%

SCC10-3/ml

Heat stress 124 28,2 3,42 3,02 460Health 120 32,5 4,02 3,46 162

Heat stress

• Worse condition

• Reproduction disorders

• Impaired general health status

Heat stress

Nutrition

• High quality fibre

• High quality concentrated feeds (by-pass fat, by-pass protein)

• Optimizing rumen function: structural fibre, roughage/concentrate ratio

• Feed should be placed in the trough early in the morning and in the evening when the ambient temperature is lower

Heat stress

Warm feed

• oxidation

• growth of yeasts and fungi

• use feed stabilizers (propionic acid, formic acid, monopropyleneglycol)

CONCLUSION

Good care of the ruminal health is a complicated task.The creation of optimum rumen conditions is based mainly on proper nutrition (balanced diet, high quality components, structural fibre, roughage : concentrate ratio, right feed additives). The healthy rumen helps eliminate the adverse effects of heat stress and achieve optimum health, performance and profitability.