[Physiological and biochemical characteristics of the digestive processes in cows of various breeds]

Physiologic experiments were carried out with four fistulated cows with anastomoses. Two of the animals belonged to the Bulgarian Brown breed, and two--to the Bulgarian Simmenthaler. Certain breed-associated aspects of the secretory activity were established concerning the amounts of chyme, the digestive juices secreted for 24 hours, and the size of absorption. The cows of the Bulgarian Brown breed, equated by all indices of analogues to those of the Bulgarian Simmenthaler took in and digested more nutrient matter of one and the same ration for 24 hours. With these animals all coefficients of digestibility were higher. The digestive processes taking place up to the duodenal anastomose and after it were shown to be more regularly distributed in Bulgarian Brown cows as a result of which they utilized more nutritive substances that passed into the blood, and gave higher produce both for 24 hours and for a lactation period. Again Bulgarian Brown cows utilized in the intestinal portion a considerably higher amount of fatty acids, which led to a higher percent of fats in the milk, although this might likewise be a genetic prerequisite. All data referred to made it reasonable to accept that the breed peculiarities of Bulgarian Brown cows should be given due consideration in fixing the composition of their daily ration.