Parts of digestive tract

The digestive tract, also known as the alimentary canal, is a tube like structure extending from the mouth to anus. The different parts of the digestive tracts of ruminants and non-ruminants are illustrated in figures. The alimentary canal is comprised of the following parts,
  1. Mouth (lips, tongue, gums and teeth) and pharynx
  2. Oesophagus
  3. Stomach (In ruminants, the stomach includes the rumen, reticulum, omasum, and abomasum)
  4. Small intestine (duodenum, jejunum, and ileum)
  5. Large intestine (caecum, colon, and rectum)
  6. Anus
In addition to the above, the following accessory organs/glands also take part in the process of digestion: salivary glands, liver, gall bladder, and pancreas.
Among domestic animals, the proportion of the digestive tract to total body weight is higher in ruminants than in non-ruminants, as shown in table. Horses, for example, have a large caecum (15.6% of the total alimentary tract) where extensive microbial fermentation of plant materials takes place. Similarly, rabbits also have a well developed caecum. In ruminants, the stomach compartments (rumen, reticulum, omasum, and abomasum) occupy the major part (62%) of the digestive tract. Large variations in the proportion of different parts of the digestive tract in farm animals reflect differences in their feeding habits. These variations have evolved over time, and the animals have gradually adapted to various feed resources.
Cattle
Buffaloes
Sheep/Goats
Horses
Dogs
Body Weight (Kg)
450
600
50
450
20


Volume in liters, and proportion of body weight (percent)
Stomach









Reticulo-rumen
97.6
(48)
130.3
(48)
10.7
(56.7)
-
-
Omasum
15.8
(7.6)
20.9
(7.6)
0.6
(3.3)
-
-
Abomasum
11.8
(5.8)
15.7
(5.8)
1.3
(6.7)
8.0
(8.9)
1.0
(63)
Small Intestine
50.9
(25)
67.7
(25)
3.8
(20)
27.0 (30.0)
0.37 (23.0)
Caecum
7.7
(3.8)
10.3
(3.8)
0.6
(3.3)
14.0 (15.6)
0.02
(1.0)
Large Intestine
19.7
(9.5)
26.0
(9.5)
1.9
(10.0)
41.0 (45.6)
0.21 (13.0)
Total
203.5
270.9
18.9
90.0
1.6