Studies of natural herbage of the sub-tropics. III. Concentrations of volatile fatty acids and ammonia in the rumen of sheep fed fresh herbage

Abstract

1. Concentrations of ammonia, volatile fatty acids, and molar proportions of acetic, propionic and butyric acids were determined in the rumen liquor of sheep fed fresh herbage harvested in the first month of growth.2. Concentrations ofammoniacal nitrogen ranged from 4·06 to 13·65 mg./1OO ml. rumen liquor with a mean value of 8·21.3. Concentrations of volatile fatty acids ranged from 7·50 to 12·20 m-moles/100 ml. rumen liquor with a mean value of 9·81. Mean molar proportions of acids were: acetic 65·8%, propionic 19·5%, n-butyric 9·0 % and higher acids 5·7 %. Differences in the proportions of acids found at different sampling times were not statistically significant.