The first three stomachs are always called forestomachs, and there are a lot of bacteria in the forestomachs, which can digest and decompose the crude fiber in feed, which is one of the main reasons why ruminants (camels and sheep) can make large use of coarse feed.
Horses and donkeys are not ruminants, they only have one stomach. Donkeys belong to mammals, Chiroptera, Equidae and Equus. Both horses and donkeys belong to Equus, also known as Erdongji, but different species have the same origin and are smaller than horses and zebras, but they share many characteristics with horses: the third toe is well developed and hoofed, and the other toes are degraded.
About ruminant feeding
1. Forage, hay and leaves are the main foods for grazing ruminants, while ruminants with economic value (goats, cows, camels, etc. Not only do you need to eat grass and stems, but you also need to eat some artificially prepared concentrate to grow fatter.
2. Ruminants have more kinds of food than other animals, and their food composition structure is more complicated. More importantly, the high crude fiber content in forage makes it difficult to digest, so most ruminants must rely on the division of labor and cooperation of four stomachs to complete the second "chewing" of food.
Extended data:
Four stomachs of ruminants
1, rumen
Food entering the "dark room" of ruminant gastrointestinal tract is the first contact and the "main battlefield" of food digestion. It is a closed living fermentation tank, in which there are many kinds of microorganisms, including protozoa, bacteria and fungi.
2, net stomach
The gastric cavity near the rumen, whose mucosa looks like a honeycomb, is also commonly known as bee-eating stomach. In fact, the reticulum and rumen are not completely separated in spatial structure, so food particles can freely shuttle back and forth between the two gastric cavities.
The food that ruminants eat in the wild often contains some foreign objects such as nails. At this time, the reticular stomach is like a sieve, which not only plays a role in filtering, but also prevents foreign bodies from harming the inner surfaces of other intestines.
In addition, the sensor on the reticulum gastric mucosa can receive mechanical stimulation signals from grass or hay, and start ruminating behavior through the contraction of muscles on the stomach wall of the tumor reticulum.
3. Stomach flap
Because its mucosal surface is depressed inward to form many lobules of different sizes, it is called double valve stomach. The digestion of food by this stomach is more like the "continuation" of rumen digestion.
It is like a water pump, where the coarse part of chyme from rumen is concentrated, further ground after removing water and electrolyte, and the thinner chyme is pushed into abomasum. In the valve stomach, 20% of the cellulose in food can be digested.
4, abomasum
The stomach cavity connected with the small intestine is also the only stomach with secretory function and real digestive function, so it is called true stomach. Abomasum can secrete a lot of gastric juice, including digestive enzymes such as hydrochloric acid, pepsin and chymosin, and a lot of mucus. These secretions mainly digest the primary metabolites of food digested by the first three stomachs further.
The muscle movement of the stomach wall mainly plays three roles: the function of storing food, the function of mixing food with gastric juice to form semi-liquid chyme and the function of emptying food. It can be seen that the four stomachs of ruminants have their own physiological digestive characteristics, but they are interrelated to complete the digestive function of food together.
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