The effect of bentonite on wool growth, liveweight change and rumen fermentation in sheep

Abstract

An experiment was conducted to evaluate the use of 3 bentonite clays in sheep. Seventy-eight Merino ewes (about 20 months of age) were housed individually and fed either a pelleted diet based on lucerne, lupins and barley or chaffed wheat-hay. The experiment consisted of an initial period (8 weeks) during which all animals received these diets without bentonite, followed by a 9-week experimental period when bentonite clays were included in the feed at a level of 25 g/kg. None of the 3 bentonite clays had any significant effect on liveweight change or wool growth in sheep fed either diet. There was also no significant effect of the clays on rumen ammonia or volatile fatty acids concentrations in sheep fed wheat chaff. In sheep fed the pelleted diet, 2 of the clay samples increased the molar proportions of acetate and decreased the molar proportion of propionate relative to the control group.