The Magical, Mystical Rumen Dr. L. E. Chase Dept. of Animal Science Cornell University

Objectives of Feeding Dairy Cattle zBalanced Total Ration and Good Feed Management yMaximize dry matter intakes yOptimize milk production yGood health and reproduction yPROFITABILITY!! yGrowth

Dairy Cattle Nutrition zWhat are we feeding? zA dairy cow? zRumen bugs?

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.

The Rumen Environment zAnaerobic zConstant temperature = 39 C zpH = 6 to 6.6 zBuffered by saliva z10-15 % dry matter zConstant mixing = motility

Generalized equation for ruminal fermentation and metabolism zCarbohydrates + zRumen bugs + yFiber fermentors yStarch + sugar fermentors zNitrogen sources + yAmmonia, peptides, and AA zAnaerobic environment + zGood environment to grow (pH, water, temperature) z Volatile Fatty Acids + yAcetate, propionate, butryate z More rumen bugs + yMicrobial protein z Methane (CH 4 ) + z CO 2 + z H 2 O + z Heat =

Rumen Bacteria z per gram z um in size z60-65% CP z80% of CP is true protein

Fiber digesting bacteria zConvert fiber to VFA’s (mainly acetate) - Cellulose, hemicellulose zLike a higher rumen pH (>6) zRequire ammonia as a nitrogen source zSlow generation interval - 8 – 10 hours to double

Sugar % Starch Digesting Bacteria zConvert sugars and starches to VFA’s - mainly propionate zLike a lower rumen pH (5.5 to 6) zRapid generation interval - Can double in < 1 hour zUse ammonia, amino acids or peptides as nitrogen sources

Rumen protozoa z per gram z um in size zMay account for 50% of the total rumen microbial mass zNot well understood

Cows & Rumens - A Symbiotic Relationship zStage 1 - The cow provides housing & nutrients for microbial growth zStage 2 - The host animal utilizes the rumen microorganisms passing to the intestines as a source of nutrients

What Does the Cow Provide? zLow oxygen environment zConstant temperature ( F) zFood for the bugs zNeutral environment zGarbage removal

What Do the Bugs Provide? zFiber digestion zHigh quality protein zVFA’s for energy and building blocks for milk synthesis zSynthesis of B vitamins zAmino acid balancing

% of Protein Requirement from Microbial Protein

Rumen CHO/Protein Balance zGood amino acid management begins with good CHO management in order to produce a high & consistent amount of AA from microbes Hoover

What’s the Economics of Microbial Protein?

Economics of Microbial Protein

Microbial Composition

Feed Crude Protein Rume n 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 Florida

Ration, Eating Rate & Saliva Production

Forage Particle Size and Chewing - Corn Silage

Particle Size - Case Study z900 cow dairy zThings going well zThen a large number of fresh cow DA’s within 1-2 weeks zFeed company was called by the producer and asked what was wrong with the ration

Corn Silage Particle Size

z“To Feed the Cow, You Need to First Feed the Bugs” z“Happy” Bugs = Milk, Health and Profit

The Manure is Your Mirror What To Look For: 1. Corn Kernels 2. Grain 3. Long Pieces of Fiber 4. Consistency - shaving cream

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 Dr. W. Stone - Cornell University

Conclusion zNeed a balanced ration of carbohydrates, protein, vitamins, minerals, fiber & effective fiber for optimal rumen function, microbial growth=maximum VFA production yMilk yields yGood health yMilk components