APSC MIDTERM

  • describe major dairy breed with average fat content (list 4)

Jersey: 4.8% 

Holstein: 3.6%

Guernsey: 4.6%

Ayrshire: 4%


  • major breed of dairy goat 

Sable

Alpine

Nubian

Saanen 


  • roles of rumen microorganisms/bacteria 

    • cellulose digestion

    • starch digestion

    • protein digestion

    • produce fatty acids 


  • explain rumen vs monogastric characteristics(3 comparisons)

  1. rumen doesn’t have amylase enzyme, monogastric has the enzyme, like silva to digest glucose 

  2. rumen has billion cells of bacteria supplying amino acids to complete micro protein synthesis. no micro protein in monogastric doesn’t supply bacteria 

  3. rumen utilizes cellulose; monastic doesn't have cellulase enzyme therefore does not produce cellulose


Major rumen volatile fatty acid 

  • Acetetic: 

  • propunic 

  • butyric 


Classify rumen bacteria

  • cellulose digesting bacteria: digest the cellulose fibers of plant cell walls by secreting hydrolytic enzymes. 

    • Fibrobacter succinogenes

    • Ruminococcus flavefaciens

    • Ruminococcus albus 

  • starch digesting bacteria: ferment all carbohydrates

    • Amylolytic Bacteria

  • acid utilizing bacteria: provides a site where the rumen microorganisms can digest carbohydrates, proteins, and fiber.

    • Anaerovibrio lipolytica

    • Fusobacterium necrophorum

    • Megasphaera elsdenii


Pictures, know and identify:

  • rumen 

  • reticulum

  • omasum

  • abomasum 


compare cow and horses digestive system 

  • horse: larger cecum, postgastric system, after cellulose 

  • cow: pregastric system 


  • Small intestine function 

The small intestine functions in digestion and absorption of nutrients and as an important barrier and immune organ in the body.


  • saliva function

  • buffering agent to protect rumen estrosis 

  • supply minerals and nutrients 

  • help swallow, mixing food 


  • describe saliva pH 

The normal pH of grass-fed ruminants is 6-7. A pH value of 5.5-6 is seen in cattle on high-grain diets or pasture-fed cattle with early lactic acidosis.




extra credit:

biological methane gas production system 

  • carbon dioxide + hydrogen produce methane gas

  • acetic acid + carbon dioxide produce methane gas 

  • Carbon dioxide + methanol produce methane gas