Rumen physical and chemical properties
Ruminants are mammals that have specialized in consuming fibrous plant material, which digestive enzymes are unable to degrade, but through the fermentation provided by the microorganisms that live in symbiosis in the rumen, they are exploited. The stomach of ruminants is made up of four compartments, rumen, reticulum, omasum and abomasum; only the latter produces digestive enzymes capable of breaking down food. The fermentation process is carried out mainly in the first two parts of the stomach. The final product of ruminal fermentative processes is volatile fatty acids, which are absorbed through the rumen wall in a buffered liquid environment close to neutrality. The knowledge of the factors that alter the physical conditions or the chemical balance of the rumen is very important because it can allow improving the production conditions and the performance of the animals. The ruminal pH decreases with increasing temperature, regardless of diet, indicating an increasing concentration of volatile fatty acids in the rumen favoured by increases in temperature. The saliva secreted by the ruminant acts as a lubricant for the food consumed, with a pH of 8.2 on average, high content of sodium, potassium, bicarbonate and phosphate, characteristics that allow it to act as a buffer in ruminal liquor. The rumen buffer system is very complex, resting on an abundant production of saliva. The intraruminal environment is anaerobic par excellence, which indicates that it is constantly in reduced conditions. The increase in the concentration of organic acids in the rumen may be the reason for the increase in osmotic pressure. Maintaining the rumen conditions uniform to guarantee optimum performance is a requirement for good production.