Digestibility of Rations for Ruminants as Affected by Proportions of Nutrients

Abstract

A study was made of the effect of supplements on the digestibility of a mixed ration for sheep. Using 5 sheep on each treatment, supplements in 2 different quantities were fed, representing crude fiber, ether extract, protein, carbohydrate and urea, respectively. The addition of crude fiber reduced the total amount of protein and ether extract digested, while the most prominent effect of added carbohydrate was to reduce the digestible crude fiber and digestible protein. Casein increased the digestibility of protein, ether extract and energy and decreased the digestibility of the crude fiber and nitrogen-free extract. Urea caused a prominent increase in the digestibility of protein while corn oil in the smaller of the two amounts fed, increased the digestibility of each feed constituent, the larger amount of corn oil having the reverse effect. An application of the “Lignin ratio” method of determining digestibility is presented which shows this procedure to be highly valid.