5B: ruminant digestive system

Question 1

name 6 animals that are ruminant

Answer 1

cattle, sheep, goat, deer, buffalo, camel

Question 2

what the helly is cud??

Answer 2

a portion of food that returns from a ruminant’s stomach to the mouth to be chewed for the second time

Question 3

what are the 4 compartments of a ruminants “stomach”?

Answer 3

reticulum, rumen, omasum, abomasum

Question 4

what is the function of the oral cavity in the ruminant digestive system?

Answer 4

• receiving, storing, grinding, lubricating food
• buffering: neutralises acidity due to fatty acids in rumen
• maintains rumen pH at ~7 through microbial activity

Question 5

what are the major and minor salivary glands in ruminants?

Answer 5

major salivary glands: parotid, mandibular, sublingual
minor salivary gland: buccal

Question 6

where is the oral vestibule?

Answer 6

lies between the gums and teeth

Question 7

where is the oral cavity proper?

Answer 7

lies behind the tooth arch

Question 8

what salivary glands are part of the oral vestibule?

Answer 8

parotid and buccal

Question 9

what salivary glands are part oof the oral cavity proper?

Answer 9

mandibular and sublingual

Question 10

what are the functions of salivary glands?

Answer 10

• saliva production via ducts
• moistens, neutralises n protects food
• protects oral cavity etc
• contains salts, HCO3, mucous, lysozyme

Question 11

how often does a cow ruminate?

Answer 11

5-7 hours, split into 6-8 rumination periods

Question 12

what is the function of rumen microbes?

Answer 12

degradation and digestion of fibrous feed components, eg
- cellulose
- hemicellulose
- lignin
- soluble CHO like starch
- proteins
- lipids
protein n vitamin synthesis
energy yield

Question 13

what is the function of the rumen?

Answer 13

• fermentation vessel, uses 50-85% of the digested organic matter (DOM) in ingested food
• receives, breaks, moves, processes food
• papillae increase surface area for microbial attachment n absorption of fermented product via rumen wall

Question 14

how are gasses caused and removed?

Answer 14

• caused as by-product of fermentation
• removed by eructation (belching), also absorption into blood stream, then removed by lungs

Question 15

what is the function of the omasum?

Answer 15

• grinds n squeezes the food
  -> removes water from food: outgoing food contains ~60% less water
• little to no digestion
• absorption of volatile fatty acids (VFAs)

Question 16

what is the function of the abomasum?

Answer 16

• adding gastric juices to undegraded feed
  -> pepsin, HCl, mucous
• little to no digestion of fat, cellulose, starch
• pH of ~3
  -> dismantles protein molecules
  -> denatures bacteria, pathogens, toxins
  -> dissolves minerals
  -> promotes gastric digestion
• turns food into a slurry

Question 17

what enzymes does the pancreas secrete? what do they do?

Answer 17

• amylase
• lipase
• proteases
  -> trypsinogen > trypsin
  -> chymotrypsinogen > chymotrypsin
  -> procarboxipeptidase > carboxypeptidase