Comparison of rotational grazing with set stocking of ewes and lambs in spring on irrigated pasture in Canterbury

Abstract

Abstract Rotational grazing was compared with set stocking of ewes rearing single lambs from the end of lambing (late September) to weaning (early December). The comparison was made over 3 years (1973, 1974, and 1975) at 24 and 28 ewes per ha, and for two of these years (1973 and 1975), was extended to include 32 ewes per ha. Rotationally-grazed ewes gained more weight than set-stocked ewes from the end of lambing to weaning, with a mean difference over 3 years of 3.4 and 5.7 kg per head at 24 and 28 ewes per ha respectively. (In the two years when the 32 ewes per ha stocking rate was included, the mean difference was 4.2 kg per head, the same as 24 ewes per ha in those years). Rotationally-grazed pasture averaged 700 kg.ha−1 more standing dry matter at weaning than set-stocked pasture (3 year mean at 24 and 28 ewes per ha). Lamb liveweight gain to weaning was similar under rotational grazing and set stocking, but decreased from 17.2 to 15.9 kg per lamb when the stocking rate increased from 24 to 28 per ha. Total lamb liveweight gain per ha increased from 413 kg at 24 ewes per ha to 445 kg at 28 ewes per ha.