Rates of production of volatile fatty acids in the rumen. V. Evaluation of fodders in terms of volatile fatty acid produced in the rumen of the sheep

Abstract

l(a). Volatile fatty acid (VFA) production (moles/12 hr) by two sheep fed at 2-hourly intervals on a constant ration containing equal parts of wheaten hay and lucerne hay, showed no significant difference between the sheep or between day-time and night-time values. The precision with which production could be measured over a series of 12-hr periods is given.

The quantities of VFA produced in the rumen on successive days varied considerably; the extent of this variation was similar to that occurring in the quantities of faeces passed.

(b) Production remained much the same whether the sheep were fed at intervals of 1, 2, or 12 hr.

(c) The energy of the VFA produced in the rumen was equivalent to about 54% of the digestible energy of the diet.

2. Similar amounts of VFA were produced from two different mixtures of wheaten hay and lucerne hay, and from lucerne hay alone.

3. A modification in the procedure for measuring VFA production was tested and found to be satisfactory. The necessary apparatus could be readily carried on the back of a freely moving sheep.