Effect of herbage allowance and concentrate food level offered to ewes in late pregnancy on ewe and lamb performance

Abstract

AbstractTwo experiments were undertaken to investigate the effect of herbage allowance and concentrate food level offered to twin-bearing ewes in the last 6 weeks of pregnancy on ewe and lamb performance. In each study, 96 twin-bearing Greyface (Border Leicester × Scottish Blackface), Rouge × Greyface and Texel × Greyface ewes were used. In experiment 1, the ewes were allocated to eight treatments consisting of two herbage allowances (1·3 and 2·6 kg herbage dry matter per ewe per day) and four concentrate food levels ranging from zero to 1000 g per day. In experiment 2, ewes were offered four herbage allowances (1·3, 1·75, 2·2 and 2·6 kg herbage dry matter per ewe per day) and zero or 500 g concentrates per day. In experiment 1, herbage allowance and concentrate food level had no significant effect on lamb birth weight, lamb mortality or lamb performance up to weaning. Herbage dry matter intake decreased linearly with increasing concentrate food level with a substitution rate of 18 g of herbage dry matter per 100 g concentrate food level. In experiment 2, lamb birth weight increased with increasing herbage allowance (P< 0·01) and with increasing concentrate food level (P< 0·01). However, lamb performance to weaning was unaffected by late pregnancy nutrition. The satisfactory levels of performance obtained with ewes offered grass-only diets in late pregnancy indicates that grazed grass is a high nutritive value food for twin-bearing ewes in late pregnancy.