Effect of time of joining and rate of stocking on the production of Corriedale ewes in southern Victoria. 4. Production of ewes born in July and September and effect of inclusion of Phalaris tuberosa in annual pasture

Abstract

The production of two groups of 56 ewes born either in the month of July or September in 1968,1969 or 1970 (a total of 336 ewes) was compared until November 1972. From weaning (1 2 weeks) to approximately 15 months of age the ewes were grazed on two types of pasture (with and without Phalaris tuberosa) at two rates of stocking (8 and 11 ewes ha -1) and thereafter ewes born in the same year grazed common pasture. Ewes lambed in August, the first lambing being at two years of age. Throughout the experiment ewes born in July remained heavier and produced heavier fleeces and heavier lambs than ewes born in September. In the first lambing (maiden ewes only) 20 per cent more lambs were weaned from ewes born in July than from ewes born in September but at later lambings differences in reproductive performance were small. Liveweight gains of ewes grazing pastures containing phalaris were 1 to 2 kg greater between November and February than those grazing pasture without phalaris. At their first lambing, ewes that had been grazing phalaris at the rate of 8 ewes ha-1 produced fewer lambs than the corresponding group grazing pasture without phalaris. Losses in production due to lambing ewes in July rather than September as previously reported are unlikely to be offset by production differences of their offspring.