THE EFFECT OF ORGANIC ACID SALTS ON GROWTH AND RUMEN VOLATILE FATTY ACIDS OF SHEEP FED PELLETED OR CHOPPED HIGH-ROUGHAGE RATIONS

Abstract

Four experiments were conducted with sheep to compare the addition of sodium citrate and sodium propionate to pelleted and unpelleted rations and to determine the response to sodium citrate supplementation of different quality-hays. There were no significant differences in rate of gain or feed consumption of a ⅔ roughage −⅓ concentrate ration due to supplementation with sodium citrate or sodium propionate. Pelleting either the mixed ration or all-roughage rations increased feed consumption and rate of gain in all experiments. Pelleting the mixed ration decreased digestibility of dry matter, organic matter, and nitrogen in the one experiment in which this was determined. Pregnant and lactating ewes lost less body weight when fed a limited amount of long hay plus pelleted hay ad libitum than similar ewes fed a standard ration of long hay ad libitum plus 0.5 lb of concentrates per day. It was necessary to feed lambs 0.5 lb of rolled barley per day with long hay ad libitum to obtain gains equal to those of similar lambs fed pelleted hay ad libitum. The addition of sodium citrate significantly increased the rate of gain of lambs fed ad libitum a slightly moldy, weathered legume hay in the pelleted form together with 0.25 lb of long hay per head per day.The addition of sodium citrate to a mixed ration or to all-roughage rations did not usually alter the proportions of rumen volatile fatty acids. The addition of sodium propionate decreased the proportion of acetic acid while increasing that of propionic acid. In both experiments where this was determined, pelleting an all-roughage ration resulted in a decrease in the proportion of acetic acid and an increase in the longer chain volatile fatty acids in rumen fluid.