The effect of sward surface height on sheep grazing activities

The objective of this study was to assess the effect of Italian ryegrass (Lolium multiflorum Lam.) sward height on grazing activities. The experiment was carried out at the Research Station of Universidade Federal do Rio Grande do Sul, Brazil. Yearling no-castrated male lambs behavior was assessed in terms of diurnal grazing, ruminating and idling time in three periods: 27 September 11 and 25 October. Sward surface height was monitored using a sward stick and samples of 0.25 m(2) were cut to ground level to estimate herbage and leaf lamina mass. The experiment was carried out in a randomised block design with three replications of four treatments: sward surface heights (5, 10, 15 and 20 cm). Grazing time and ruminating time were somewhat interchangeable, decreasing grazing time and increasing ruminating time with increasing sward surface heights. Idling time remained relatively constant. Sward height showed a small effect on biting rate.