[Effect of the diet containing rendering fats on the milk yield and vitamin E content in the milk of dairy cows]. / Vliv diet s prídavky kafilerních tuku na mlécnou uzitkovost a na obsah vitamínu E v mléce dojnic.

ABSTRACT

In three groups of first-calvers with 15 animals each, with an identical basal diet, we followed for six months the effect of the DOB mixture additive without fat, the DOB mixture with 5% of rendering-plant fat obtained mechanically and DOB with 5% of rendering-plant fat after perchlorethylene extraction (0.90% perchlorethylene residuum). This additive of rendering-plant fats in concentrate mixtures as a substitute for grain in our experiment increased milk efficiency and the production of milk fat parallelled by a saving of concentrated feeds. An addition of rendering-plant fats which were often of low quality resulted in a decrease in vitamin E content in the blood serum and milk.