Physico-chemical conditions in the rumen of Bedouin goats: effect of drinking, food quality and feeding time

Abstract

SummaryIn Bedouin goats maintained outdoors during the summer, fed lucerne hay and watered once daily, drinking was followed by a 35% increase in rumen fluid volume, with a concomitant drop in osmolality from 300 to 150 m-osmol/kg. When water was provided to these goats only once every 4 days, a three-fold increase in the rumen fluid volume was recorded and osmolality dropped from 360 to 80 m-osmol/kg.Feeding, which was depressed during the hot hours of the day, resumed in the afternoon and was followed by an expansion of rumen fluid volume. This expansion occurred irrespective of drinking and was sustained throughout the night. On the 1st day of water denial it amounted to 40% of the noontime rumen fluid volume and was less pronounced during the rest of the water deprivation period. An evening increase in the concentrations of volatile fatty acids, along with a compatible increase in the osmolality and a drop in the pH, also followed the afternoon resumption of feeding.In goats maintained on wheat straw, drinking as well as feeding time affected the physico-chemical conditions in the rumen to a lesser degree than in goats maintained on lucerne hay.