General Animal Science (copy)

monogastrics

animals with a simple stomach (humans, pigs,chickens,dogs,cats)

ruminants

animals with a “complex” four- \n compartment stomach ( mostly herbivores :cattle, sheep,deer,goats)

Hind-gut fermenters

animals that have a \n simple stomach but also a large cecum that \n helps to digest fibrous feeds (horses, \n rabbits, and ostriches)

cecum

provides a location for additional \n microbial digestion

Mechanical digestion

mostly refers to chewing (mastication) but can also involve muscular \n contraction of the GIT

Chemical digestion:

refers to enzymatic and acid digestion of feedstuffs

Microbial digestion

refers to the digestion of feedstuff by microbes (they can produce \n enzymes that the animal itself cannot)

Accessory GIT organs

\n Salivary glands,Liver, Gall Bladder,Pancreas

Major anatomical parts of the GIT include

Mouth \n • Esophagus \n • Stomach – (variable based on species) \n • Small intestine \n • Cecum \n • Large intestine (colon) \n • Rectum

Prehension

this is means with which an animal brings \n food to its mouth

Mastication

\n Feed is ground by the teeth in a process called

bolus

The mixture of ground feed and saliva is referred \n to as a

peristalsis

\n A type of involuntary movement called peristalsis \n helps to move the bolus down the esophagus \n towards the stomach

ruminant stomach

\n The ruminant stomach is “complex” and has \n four compartments

rumen

The rumen is the largest compartment

The inner lining of the rumen is covered in \n finger-like projections called papillae

The rumen also acts as storage for food

Microbial fermentation

Continuous fermentation in the rumen often leads to excessive gas production

Eructation

The technical name for belching is

Rumination

regurgitating food in the stomach \n and re-chewing it( referred to as “chewing cud”)

Reticulum

\n Has a “honeycomb” appearance

Any metal debris consumed by the animal will \n be collected here

\

Omasum

• The third compartment of the stomach \n • Appears to have numerous “pages” or “leaves” \n • Commonly called the “butchers bible” \n • Increases surface area for absorption

Abomasum

\n referred to as the “true stomach” \n • This final compartment of the ruminant \n stomach is analogous to the monogastric \n stomach \n • Very similar in shape \n • More chemical digestion

\n Duodenum

\n the first section of the small intestine where the chyme arrives from the \n stomach

\n Jejunum:

\n the middle section of the small intestine. This section is the largest and is where most absorption occurs

Ileum:

this is last section of small intestine that filters into the cecum

enterocytes

Absorption of nutrient occurs via the \n enterocytes

Stem cells:

help create new enterocytes in the \n crypts

Goblet cells

produce mucus

Paneth cells:

release anti-microbial peptides to \n assist with defense

Enteroendocrine cells:

release hormones