The intake of grass and rush (Juncus effusus L.) by goats grazing rush‐infested grass pasture

AbstractThe intakes of rush and grass by goats grazing rush‐infested reseeded pasture (rush ground cover, 5.9%) were measured in three periods between July and September in one year, using n‐alkanes as dietary markers. Diet composition and intakes were measured at intertussock sward heights maintained at 3–4 cm and 5–6 cm and at an intertussock sward height maintained at 3–4 cm where the rushes had previously been grazed by goats to reduce rush green stem height to 0.75 of that of ungrazed tussocks.There was no effect of intertussock sward height or initial rush green stem height on the dietary proportion (overall mean 0.51) or dry matter (DM) intake of rush but there was an effect of period, which was related to changes in sward conditions over the experiment. Rush intake was positively related to the amount and accessibility of green rush stems and grass intake to intertussock sward height. Digestibility of DM of the diet, measured using n‐alkanes, was high (overall mean 0.71), suggesting that the nutritive value of the rush is greater than previously estimated from in vitro digestibility measurements. Under these conditions, it appears that the goats select a mixed diet and the results are consistent with animals selecting food items to maximize their rate of nutrient intake.