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Effects of autumn shearing of spring-born ewe lambs on liveweight and reproductive performance



Effects of autumn shearing of spring-born ewe lambs on liveweight and reproductive performance



Irish Journal of Agricultural & Food Research 33(2): 131-139



Ewe lambs have a lower incidence of mating and a lower conception rate than adult ewes. There is evidence that these reproductive characteristics can be improved by shearing prejoining. The effects of shearing spring-born ewe lambs in autumn on subsequent liveweight and reproductive performance were evaluated in an experiment repeated over 3 years. Half of the flock was shorn in mid-September and half remained unshorn. All were managed together as a single group thereafter. Fertile harnessed rams were joined on 16 October each year and removed in early December. Matings were recorded daily and ovulation rate was determined by laparoscopy within 10 days of first mating. Shearing had no significant effect on liveweight but liveweight gain between shearing and joining was lower for the shorn animals (P lt 0.05). The proportion mated (shorn 93%, unshorn 96%) and overall conception rate (shorn 73%, unshorn 76%) were unaffected by treatment. While there was no overall effect of shearing on conception rate to first service (P gt 0.3) there was a year times shearing interaction (P lt 0.05). In the first year, shorn ewes had a higher conception rate but the opposite effect was observed in the second year. Shearing had no significant effect on the date of first service, on ovulation rate or on embryo survival in those ewes which conceived to first service. The reproductive performance of ewe lambs which lambed, in terms of ovulation rate, number of services to conception, conception date, lambing date, litter size and gestation length, was unaffected by shearing. Shorn ewes tended to give birth to heavier lambs but the difference (0.2 kg) did not reach significance (P = 0.2). In this study, shearing prior to joining did not enhance the reproductive performance of ewe lambs.

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Accession: 002606718

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DOI: 10.2307/25562227


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