Rumen Function and Feedstuffs

What feeds have the highest concentration of structural carbs?

Forages

What are the fibrous by-products of the lant cell wall?

Soybean hulls

Wheat midds

Distillers grains

What feeds have high concentration of non-structural carbs?

Cereal grains

What are the non-structural carbs?

Amylose

Amylopectin

What are the protein types?

Nonprotein nitrogen (NPN)

Rumen degradable protein (RDP)

Rumen undegradable protein (RUP)

Bacterial/microbial crude protein

What is an example of an NPN (non-protein nitrogen)?

Urea

What is unique about amino acids in rumeninants?

They can synthesize their own amino acids

What feeds have high crude protein concentration?

Oilseed meals (soybean, cottonseed)

Animal by-products (fishmeal, meat and bone meal)

What feeds have high rumen degradable protein concentration?

Oilseed meals

What feeds have high rumen undegradable protein concentration?

Animal by-products

What is the function of the rumen?

Fermentation processes and end-product synthesis

What occurs during fermentation?

Pyruvate is converted to a VFA (acetate, propionate, butyrate) because they cannot finish glycolysis without oxygen

What is acetate used for?

Energy and fat synthesis

What is proprionate used for?

Energy and glucose synthesis

What is butyrate used for?

Rumen epithelium energy

What happens to the extra carbon when acetate is made?

They lose a carbon due to methane

How many carbons are lost when propionate is made?

None

What are the classes of nutrients?

Carbs, proteins, lipids, vitamins, minerals, water

What are the types of carbs?

Structural and nonstructural

What are the types of protein for rumens?

Degradable and undegradableproteins; degradable proteins can be broken down by microbes, while undegradable proteins pass through the rumen intact.

What are types of structural carbs?

Cellulose, hemicellulose, lignin, and pectin

What are types of nonstructural carbs?

Starches and sugars

Amylose and amylopectin are the major starches

What is unique about lignin?

Technically not a carb but is a major component of structural carbs in forgages fed to ruminants

When do lignin concentrations increase in plants?

As they age they get more lignin which is less digestible

What is energy?

not a nutrient but a requirement

What is the importance of different types of carbohydrates and protein?

Different forms will provide different amounts of energy (if low energy need more nonstructural carbs)

What are the major groups of rumen micrflora?

Cellulolytic, amylolytic, proteolytic, lactic acid utilizing, methanogenic

What are the fiber fermenters?

Cellulolytic

What are the starch fermenters?

Amylolytic

What are the protein degraders?

Proteolytic

How are rumen microflora classified?

Substrate specificity

What causes a shift in acetate:proprionate ratio?

Change in microbial species causing a decrease in pH resulting in acetate and increase in propionate

Concentration of acetate going down because as pH increases, propionate is made more because it takes 2 hydrogen to be created

What drives pH in the rumen?

Rate of fermentation (add starch increases acid fast)

Animals ability to buffer with bicarb from saliva

What happens to rumen degradable protein in the rumen?

Some of them use preformed aa from forage

Some use ammonia from the plants to create bacterial crude protein and digested by animal in SI

some are goes trough the liver and back to saliva

some goes to urea and turns into urine

What happens to rumen indegradeable protein in the rumen?

Passes into the small intestine

What are the 3 fates of NH3/urea?

Excreted in urine

Reabsorbed across rumen epithelium

Recycled to rumen via saliva

What is the significance of the ruminants ability to recycle NH3/urea?

Helps them maintain nitrogen in the winter or allows us to supplement protein every few days due to recycling

What do ruminants do with fatty acids?

Do not really break them down just convert to different forms

What is the significance of lipid bio-hydrogenation?

Causes beef to have high saturated fat

Difficult to change fatty acid profile of beef

Why is moisture important in diet?

You cannot compare feedstuff if they all have different amounts of moisture, need to use dry matter %

What is ADICP?

Estimate of what protein is not digestible in a feed

what is aNDF?

Total amount of fiber

What is NFC?

Non structural carbs in a feed

What is TDN?

Total digestible nutrients