Diet preferences of adult sheep and goats grazing ryegrass and white clover

Abstract

The dietary preferences for perennial ryegrass ( Lolium perenne L.) and white clover ( Trifolium repens L.) of sheep ( Ovis aries L.) and goats ( Capra hircus L.) have been tested. The 12 test plots comprised monocultures of grass alongside monocultures of clover with either 20% clover: 80% grass or 80% clover: 20% grass by area. The behaviour of the animals was recorded automatically during three consecutive days, and the position of the animals in relation to the herbage species was recorded by video cameras during the hours of daylight. Dietary preference, defined as time spent grazing clover as a percentage of total time spent grazing clover and grass, differed from random and differed from a monospecific preference. During daylight sheep grazed significantly ( P = 0.010) longer than goats (485 versus 400 SED ± 31.3 min), and the extra time spent grazing by sheep was mainly on clover (327 versus 206 SED ± 46.9 min; P = 0.032). These grazing times showed that sheep had a 70% preference for clover and goats had a 52% preference for clover. These values were not significantly different, but the animals may not have been able fully to exhibit their preferences because of physical constraints on diet selection due to a reduction in sward height during the experiment.