Introduction

• Refers to breaking down of complex compounds to simple one before they pass through the mucus membrane of the alimentary canal and then into the blood and lymph.
• Depending upon the structure of digestive tract, the animal can be classified into two groups:

1. Non-ruminant: having simple stomach. Eg: Dog, Pig, birds, etc.
2. Ruminant: having four compartmental stomach i.e. rumen, reticulum, omasum and abomasum. Eg: Cow, Goat, Sheep, etc.

• Depending on the feed habit, domestic animals are grouped into

1. Carnivores: Dog, cat, tiger, etc.
2. Herbivores: Sheep, goat, horses, rabbit, etc.
3. Omnivores: Bear, Jackal, etc.

Process of digestion

1. Mechanical : Done by mastication, chewing of cud and muscular contraction of alimentary canal.
2. Chemical: Done by enzymes secreted in the different organs of digestive tract.
3. Microbial: Done by action of bacteria and protozoa present in rumen of ruminants and large intestine of non-ruminants.