Prime lamb production in relation to time of mating [sheep]
1994
Freer, M. | Donnelly, J.R. | Axelsen, A. | Dove, A. (Commonwealth Scientific and Industrial Research Organisation, Canberra (Australia). Div. of Plant Industry) | Fowler, D.G. (New South Wales Agriculture, Glen Innes (Australia))
Over 3 years, the possible benefits were examined of moving the joining date from mid March to early February for the productivity of a prime lamb system based on Border Leicester x Merino ewes on the southern tablelands of New South Wales. The proportion of ewes with 1 or more lambs (fertility) was affected more by year and by age of ewe than by joining date. Groups of ewes, balanced for fetus number, grazed at 6.5, 10, or 13 per ha on pastures based on phalaris and subterranean clover. Ewe liveweight after lambing, lamb birthweight, and perinatal mortality were not affected by joining date, but mean daily weight gain by later born lambs over the first 90 days of life was 44 g greater than for earlier born lambs. The results suggest that prime lamb system in this environment is more likely to succeed with the earlier joining date. The lower lambing percentage, resulting from a decrease in fecundity, is likely to be of benefit, rather than detriment, to the efficiency of a system in which single- and twin-bearing ewes and their lambs are given equivalent treatment.
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