Dairy Cow Feeding

Concentrate will ….. ….. of rumination

Decrease time (lower particle size)

Products of rumen microbes

• VFA

• Vitamins

• Microbial proteins

Which enzyme microbe produce to digest cellulose

Cellulase

Rumen microbes can also serve as

Feed source, provide AA and energy, digested in abomasum

Energy leave the rumen as form of

• VFA

• Microbes

• Digestible unfermented feed

Saliva of ruminants is rich in …

Urea; source of N for microbes

Methane is produced by in rum

Methane-producing bacteria

How ruminants digest starch

Don’t have amylase in saliva; digested by amylolytic bacteria and pancreatic amylase

Fungi in rumen

• Low number

• Digest recalcitrant fibers

Protozoa in rumen

• Digest carb, proteins and fat

How microbes digest lipids

• Lypolysis (TAGs = glycerol + 3 FA)

• Biohydrogenation (Unsaturated FA become more saturated by adding of H; less double bonds)

Too much TAGs and unsaturated FA, leads to

• Less methane prod

• Less fiber digestion

• Produce trans FA (less milk fat)

Classification of proteins in ruminant diet

• Dietary protein

  • Rumen Degradable Prot

  • Rumen Undegradable Prot

• Dietary non-protein nitrogen

In rum, where proteins are absorbed

Small intestine

What Microbial Crude Protein need for their synthesis

• Energy

• Nitrogen

• Carbs (for carbon backbones)

There is an excess of ammonia in the blood, what happens

• Converted to urea in the liver (2 ammonia mol, non toxic)

• Urea is excreted in urine and return to rumen via saliva

• Can cause ammonia toxicity

Is protein quality of RDP important

No, microbes will transform them in good microbial proteins no matter what

Is quality of RUP important

Yes, as they’re not modified in rumen

In rumen carbs are transformed into

VFA

VFA can be transformed into

• Acetate

• Butyrate

• Propionate

Propionate role

Gluconeogenesis

Butyrate role

Ketonogenesis, development of rumen wall and papillae

Acetate role

FA synthesis

Major energy sources in rum

Acetate and butyrate

Is there protease in ruminants saliva

No

Who digest proteins in ruminants and where

Bacteria & protozoa in rumen

Main source of NPN in rumen

Urea

What happens to escape protein

Digested in abomasum and small intestine

Who produce VFA

Amylolitic bacterias