Rumen digestion process of ruminants

Ruminants usually eat in a hurry, especially roughage, and most of them are swallowed into the rumen without full chewing. Food is soaked and softened in rumen for a period of time, then retched and returned to mouth, chewed, mixed with saliva again and swallowed into rumen again. Except for camels and llamas, these animals have no upper front teeth, but hard gums at corresponding positions to support what the lower front teeth bite. When ruminants eat, they first roughly chew the food (mainly vegetation and twigs) and then swallow it, then lie down or sit down, return the food to their mouths and chew it again.

The digestive physiology of ruminants is completely different from that of monogastric mammals and much more complicated than that of monogastric mammals. Monogastric mammals break down three nutrients-sugar, lipid and protein-into simpler forms through digestive juice and then absorb them, and then use these substances to maintain the energy needed for their own physiological activities or to synthesize various substances needed for their own metabolism, growth, development and reproduction. In monogastric animals, sugar is usually broken down into monosaccharides (glucose, fructose, galactose, mannose, etc. ) and disaccharides (maltose, sucrose and lactose) are decomposed by digestive juice, and these sugars are oxidized in the body after being absorbed to produce energy needed for metabolic activities or synthesized into fat reserves; Fat is the decomposition of higher lipids into triglycerides or other lower lipids under the action of digestive juice, which is absorbed as an energy source or a newly synthesized autologous fat reserve; Protein is hydrolyzed into amino acids under the action of digestive juice, and amino acids are used as building blocks for the synthesis of autologous protein [1]. In ruminants, they don't directly digest and absorb nutrients in feed by themselves. No matter what kind of nutrient it is, it must be fermented by rumen microorganisms first. Organic acids and some primary fatty acids produced in the fermentation process can be absorbed by rumen as the energy source of its metabolism, while other nutrients come from the digestion of rumen microorganisms. It can be said that protein, sugars and lipids of rumen microorganisms are the most important, direct and efficient nutritional sources for ruminants [1]. Therefore, in the feeding of ruminants, we must pay attention to the nutritional needs of rumen microorganisms, fully meet the nutrition of microbial reproduction and the demand for mineral elements, so as to maximize the proliferation of rumen microorganisms and enable ruminants to obtain more bacterial nutrition. The proliferation of rumen microorganisms can transform more non-protein nitrogen into bacterial proteins that can be used by cattle and sheep, which is of great significance for improving the feed utilization rate and nutrition level of ruminants. Minerals play a dual role in ruminant nutrition, which is not only necessary for maintaining normal metabolism of animals, but also necessary for rumen microbial reproduction. Fully satisfying the requirement of rumen microorganisms for minerals plays an important role in improving feed conversion rate.