Herbage intake and grazing behaviour in ewes of four breeds at different physiological states

Abstract

The digestible organic matter intakes (DOMI) of dry, pregnant, and lactating Border Leicester x Merino, Merino, Corriedale and Dorset Horn ewes of similar age were estimated when they were grazing Phalaris tuberosa –Trifolium subterraneum pastures at four levels of pasture availability. Both total DOMI and DOMI per unit liveweight differed significantly between breeds, reproductive states and pasture levels. No interactions were detected. In absolute terms the intake of 140 Corriedales = 121 Merinos = 116 Border Leicester x Merinos = 100 Dorset Horns. In terms of intake per unit liveweight Corriedales and Border Leicester x Merinos ate less than Merinos and Dorset Horns. DOMI was greater in pregnant or lactating than in dry ewes; it also increased at higher levels of available pasture. Different intakes were achieved by variation in grazing times and/or rates of intake. The ewes of all breeds responded in the same way.