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Genetic parameters for lamb birth weight in spring and autumn lambing

Published online by Cambridge University Press:  02 September 2010

S. A. Al-Shorepy  and
D. R. Notter
S. A. Al-Shorepy
Affiliation:
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0306, USA
D. R. Notter
Affiliation:
Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0306, USA
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Abstract

Genetic parameters for birth weight were estimated for two sets of spring-born and one set of autumn-born lambs of the same breed composition and genetic origin using a model that included random additive, additive maternal, permanent environmental maternal, litter and residual effects. Litter effects were significant for all data sets, indicating that within-year effects of common environment and (or) non-additive genotype were important for birth weight and should be included in genetic evaluation programmes. Estimates of variance components for autumn-born lambs differed significantly from those obtained from spring-born lambs or from the combined data. In contrast, estimates obtained for the two sets of spring-born lambs did not differ from those obtained when data on all spring-born lambs were pooled. The estimate of h2 for birth weight in spring-born lambs was over twice as large as that obtained for autumn-born lambs (0·26 v. 0·22).In contrast, the across-year repeatability of ewe effects was much larger in autumn lambs (0·41 v. 0·26) as was the full-sib littermate correlation (0·73 v. 0·49). Mean birth weights were also 0·4 to 0·6 kg less in autumn lambs. These results suggest that negative effects on birth weight that have been reported for lambs gestated during summer in equatorial and subtropical regions are also manifested (albeit at reduced levels) in less extreme climates (in this case, 37°, 15' N latitude and 654 m elevation) and that maternal variation exists in the ability of the ewe to maintain adequate lamb birth weights in autumn lambing systems.

Keywords

birth weightgenetic parametersseasonal variationsheep
Type
Research Article
Information
Animal Science , Volume 67 , Issue 2 , October 1998 , pp. 327 - 332
Copyright
Copyright © British Society of Animal Science 1998

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References

Alexander, G. and Williams, D. 1971. Heat stress and the development of the conceptus in domestic sheep. Journal of Agricultural Science, Cambridge 76: 53–72.Google Scholar
Al-Shorepy, S. A. and Notter, D. R. 1996. Genetic variation and covariation for ewe reproduction, lamb growth, and lamb scrotal circumference in a fall-lambing sheep flock. Journal of Animal Science 74: 1490–1498.Google Scholar
Al-Shorepy, S. A. and Notter, D. R. 1997. Response to selection for fertility in a fall lambing sheep flock. Journal of Animal Science 75: 2033–2040.Google Scholar
Boldman, K. G., Kriese, L. A. and Van Vleck, L. D. 1993. A manual for use of MTDFREML. Agricultural Research Service, US Department of Agriculture, Washington, DC.Google Scholar
Bolt, D. J. and Bond, J. 1989. Effects in pregnant beef heifers grazing fungus-infected tall fescue on birth weight, milk yield and calf growth. Nutrition Reports International 40: 487–494.Google Scholar
Bond, J., Lynch, G. P., Bolt, D. J., Hawk, H. W., Jackson, C. Jr and Wall, R. J. 1988. Reproductive performance and lamb weight gains for ewes grazing fungus-infected tall fescue. Nutrition Reports International 37: 1099–1115.Google Scholar
Bond, J., Lynch, G. P. and Jackson, C. 1980. Blood parameters and growth of ewes grazing tall fescue. Journal of Animal Science 51: (suppl. 1) 231 (abstr.).Google Scholar
Fogarty, N. M. 1995. Genetic parameters for live weight, fat and muscle measurements, wool production and reproduction in sheep; a review. Animal Breeding Abstracts 63: 101–143.Google Scholar
Fossceco, S. L. and Notter, D. R. 1995. Heritabilities and genetic correlations of body weight, testis growth and ewe lamb reproductive traits in crossbred sheep. Animal Science 60: 185–195.Google Scholar
Koots, K. R., Gibson, J. P., Smith, C. and Wilton, J. W. 1994a. Analyses of published genetic parameter estimates for beef production traits. 1. Heritability. Animal Breeding Abstracts 62: 309–338.Google Scholar
Koots, K. R., Gibson, J. P. and Wilton, J. W. 1994b. Analysis of published genetic parameter estimates for beef production. 2. Phenotypic and genetic correlations. Animal Breeding Abstracts 62: 825–853.Google Scholar
Morris, S. T. and McCutcheon, S. N. 1997. Selective enhancement of growth in twin foetuses by shearing ewes in early gestation. Animal Science 65: 105–110.CrossRefGoogle Scholar
Notter, D. R. and Copenhaver, J. S. 1980. Performance of Finnish Landrace crossbred ewes under accelerated lambing. II. Lamb growth and survival. Journal of Animal Science 51: 1043–1050.Google Scholar
Notter, D. R. and Hough, J. D. 1997. Genetic parameter estimates for growth and fleece characteristics in Targhee sheep. Journal of Animal Science 75: 1729–1737.Google Scholar
Schmidt, S. P., Danilson, D. A., Holliman, J. A., Grimes, H. W. and Webster, W. B. 1986. Fescue fungus suppresses growth and reproduction in replacement beef heifers. Highlights of agricultural research, South Carolina Agricultural Experiment Station, Clemson, South Carolina, vol. 33, pp. 150–151.Google Scholar
Shelton, M. 1964a. Relationship of birth weight to death losses and to certain production characters of fall-born lambs. Journal of Animal Science 23: 355–359.Google Scholar
Shelton, M. 1964b. Relationship of environmental temperature during gestation to birth weight and mortality of lambs. Journal of Animal Science 23: 360–364.Google Scholar
Shelton, M. and Houston, J. E. 1968. Effects of high temperature stress during gestation on certain aspects of reproduction in the ewe. Journal of Animal Science 27: 153–158.Google Scholar
Smith, G. M. 1977. Factors affecting birth weight, dystocia and preweaning survival in sheep. Journal of Animal Science 44: 745–753.Google Scholar
Thompson, F. N. and Stuedemann, J. A. 1993. Pathophysiology of fescue toxicosis. Agriculture, Ecosystems and Environment 44: 263–281.Google Scholar
US Department of Commerce. 1987–1993. Climatological data: Virginia, volumes 97-103. US Department of Commerce, National Oceanic and Atmospheric Administration, National Climatic Data Center, Asheville, North Carolina.Google Scholar
Yeates, N. T. M. 1958. Foetal dwarfism in sheep—an effect of high atmospheric temperature during gestation. Journal of Agricultural Science, Cambridge 51: 84–89.Google Scholar