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Effects of breed, rapid inbreeding, crossbreeding and environmental factors on fleece weight and fleece shedding in sheep

  • G. Wiener (a1), G. J. Lee (a1) and J. A. Woolliams (a1)

Abstract

Fleece weight and shedding score, a measure of premature fleece loss, were examined at first shearing and in older female sheep of three hilt breeds and their reciprocal crosses. Starting from a non-inbred base, the sheep were mated, mostly by younger-parent × offspring, for four generations, to produce inbreeding coefficients from 0·25 to 0·59. Crosses of inbred lines were also produced within breed type. The experimental design allowed the effects of inbreeding of the individual to be separated from the effects of maternal inbreeding.

Inbreeding of the individual significantly and linearly reduced fleece weight. This effect was still apparent after adjustment for body weight. Maternal inbreeding significantly reduced only the weight of first fleeces, but the trends were similar at the later ages, especially among the purebreds. There was no significant interaction of purebred/crossbred status with level of inbreeding. Inbreeding did not significantly affect shedding score. The pure breeds and the crosses did not differ, on average, in fleece weights or shedding scores, but within the purebred and within the crossbred classes breed variation was significant. Fleece weight declined and the incidence of shedding increased with increasing age. The larger the number of lambs born in the year of shearing the lower the fleece weight and the greater the extent of fleece shedding.

The effects of inbreeding could not be fully explained, statistically, in terms of dominance alone. Therefore, it seems probable that epistasis also plays a role in producing the observed changes with inbreeding in these traits.

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References

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Clark, J. E., Roden, J. A., Macpherson, O. and English, P. R. 1991, A study of premature wool loss in sheep. Animal Production 52: 585586 (abstr.).
Ercanbrack, S. K. and Knight, A. D. 1991. Effects of inbreeding on reproduction and wool production of Rambouillet, Targhee and Columbia ewes, journal of Animal Science 69: 47344744.
Harvey, W. R. 1977. Users' guide to LSML76. Mixed model least squares and maximum likelihood program. Ohio State University, Columbus.
Lamberson, W. R. and Thomas, D. L. 1984. Effects of inbreeding in sheep: a review. Animal Breeding Abstracts 52: 287297.
Ryder, M. L. and Stephenson, S. K. 1968. Wool growth. Academic Press, London.
Slee, J. 1959. Fleece shedding, staple length and fleece weight in experimental Wiltshire Horn-Scottish Blackface sheep crosses. Journal of Agricultural Science, Cambridge 53: 209222.
Schinkel, P. G. and Short, B. F. 1961. The influence of nutritional level during pre-natal and early post-natal life on adult fleece and body characters. Australian Journal of Agricultural Research 12: 176202.
Wiener, G. 1967. A comparison of the body size, fleece weight and maternal performance of five breeds of sheep kept in one environment. Animal Production 9: 177195.
Wiener, G., Lee, G. J. and Woolliams, J. A. 1992a. Effects of rapid inbreeding and of crossing inbred lines on the body weight growth of sheep.Animal Production 55: 8999.
Wiener, G., Lee, G. J. and Woolliams, J. A. 1992b. Effects of rapid inbreeding and of crossing inbred lines on the growth of linear body dimensions of sheep. Animal Production 55: 101114.
Wiener, G., Lee, G. J. and Woolliams, J. A. 1992c. Effects of rapid inbreeding and of crossing inbred lines on conception rate, prolificacy and ewe survival in sheep. Animal Production 55: 115121.
Woolliams, J. A. and Wiener, G. 1980. The effects of breed, crossbreeding and other factors on variation in fleece and skin traits. Animal Production 30: 417429.
Woolliams, J. A. and Wiener, G. 1981. The effect of breed type and inbreeding on characteristics of the fleece and skin of 12-week-old lambs. Animal Production 32: 922.

Keywords

Effects of breed, rapid inbreeding, crossbreeding and environmental factors on fleece weight and fleece shedding in sheep

  • G. Wiener (a1), G. J. Lee (a1) and J. A. Woolliams (a1)

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