Dr L E Chase Dept of Animal Science Cornell University Objectives of Feeding Dairy Cattle Balanced Total Ration and Good Feed Management Maximize dry matter intakes Optimize milk production ID: 348753
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Slide1
The Magical, Mystical Rumen
Dr. L. E. Chase
Dept. of Animal Science
Cornell UniversitySlide2
Objectives of Feeding Dairy Cattle
Balanced Total Ration and Good Feed Management
Maximize dry matter intakes
Optimize milk production
Good health and reproduction
PROFITABILITY!!
GrowthSlide3
Dairy Cattle Nutrition
What are we feeding?
A dairy cow?
Rumen bugs?Slide4
Bug Managers
Don’t think of it as feeding the cow,
you are feeding the bacteria or “bugs”
that live in the cow’s rumen.
The bugs in the rumen take the nutrients in
the feed and turn it into milk, milk fat & protein,
growth, and to nourish their growing calf.Slide5Slide6Slide7Slide8Slide9Slide10
The Rumen Environment
Anaerobic
Constant temperature = 39 C
pH = 6 to 6.6
Buffered by saliva
10-15 % dry matter
Constant mixing = motilitySlide11
Generalized equation for
ruminal
fermentation and metabolism
Carbohydrates +
Rumen bugs +
Fiber fermentors
Starch + sugar fermentors
Nitrogen sources +Ammonia, peptides, and AAAnaerobic environment +Good environment to grow (pH, water, temperature)
Volatile Fatty Acids +
Acetate, propionate, butryate
More rumen bugs +
Microbial protein
Methane (CH
4
) +
CO
2
+
H2O +Heat
=Slide12
Rumen Bacteria
10
9
- 10
11
per gram
0.3 - 50 um in size
60-65% CP80% of CP is true proteinSlide13
Fiber digesting bacteria
Convert fiber to VFA’s (mainly acetate) - Cellulose,
hemicellulose
Like a higher rumen pH (>6)
Require ammonia as a nitrogen source
Slow generation interval - 8 – 10 hours to doubleSlide14
Sugar % Starch Digesting Bacteria
Convert sugars and starches to VFA’s - mainly propionate
Like a lower rumen pH (5.5 to 6)
Rapid generation interval - Can double in < 1 hour
Use ammonia, amino acids or peptides as nitrogen sourcesSlide15
Rumen protozoa
10
5
- 10
6
per gram
20 - 200 um in size
May account for 50% of the total rumen microbial massNot well understoodSlide16
Cows & Rumens - A Symbiotic Relationship
Stage 1 - The cow provides housing & nutrients for microbial growth
Stage 2 - The host animal utilizes the rumen microorganisms passing to the intestines as a source of nutrientsSlide17
What Does the Cow Provide?
Low oxygen environment
Constant temperature (99 - 106
0
F)
Food for the bugs
Neutral environment
Garbage removalSlide18
What Do the Bugs Provide?
Fiber digestion
High quality protein
VFA’s for energy and building blocks for milk synthesis
Synthesis of B vitamins
Amino acid balancingSlide19
% of Protein Requirement from Microbial ProteinSlide20
Rumen CHO/Protein Balance
Good amino acid management begins with good CHO management in order to produce a high & consistent amount of AA from microbes
HooverSlide21
What’s the Economics of Microbial Protein?Slide22
Economics of Microbial ProteinSlide23
Economics of Microbial ProteinSlide24
Microbial CompositionSlide25
Feed
Crude Protein
Rumen
Ammonia
Microbes
Escape Feed Protein
Urine
Manure
Recycled
Carbohydrates
VFA
Liver
Urea
Milk
Excess
Protein
Recycled
Production &
Maintenance
Absorbed
Protein
Dr. M. B. Hall - Univ. of FloridaSlide26
Ration, Eating Rate & Saliva ProductionSlide27
Forage Particle Size and Chewing - Corn SilageSlide28
Particle Size - Case Study
900 cow dairy
Things going well
Then a large number of fresh cow DA’s within 1-2 weeks
Feed company was called by the producer and asked what was wrong with the rationSlide29
Corn Silage Particle SizeSlide30
“To Feed the Cow, You Need to First Feed the Bugs”
“Happy” Bugs = Milk, Health and ProfitSlide31
The Manure is Your Mirror
What To Look For
:
1. Corn Kernels
2. Grain
3. Long Pieces
of Fiber
4. Consistency -
shaving creamSlide32
The Big Balancing Act...
Effective
fiber
Salivary buffers
Ruminal mixing
Rumen
Fermentable
Carbohydrates
Acid production
Environment
Stall comfort
standing vs lying
Heat stress
Over-crowding
Diet consistency
Stress
Dr. W. Stone - Cornell UniversitySlide33Slide34
Conclusion
Need a balanced ration of carbohydrates, protein, vitamins, minerals, fiber & effective fiber for optimal rumen function, microbial growth=maximum VFA production
Milk yields
Good health
Milk components