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Genetic studies of prolificacy in New Zealand sheep

Published online by Cambridge University Press:  02 September 2010

G. H. Davis ,
C. A. Morris  and
K. G. Dodds
G. H. Davis
Affiliation:
1AgResearch, Invermay Agricultural Centre, PB 50034, Mosgiel, New Zealand
C. A. Morris
Affiliation:
2AgResearch, Ruakura Agricultural Research Centre, PB 3123, Hamilton, New Zealand
K. G. Dodds
Affiliation:
1AgResearch, Invermay Agricultural Centre, PB 50034, Mosgiel, New Zealand
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Abstract

Data on ovulation rate, embryo survival and litter size have been analysed from the 1988-96 records collected at AgResearch's Woodlands Research Station on 2180 elite (highly prolific) ewes of three breeds: Romney, Coopworth and Perendale. The Romneys included a subgroup found to carry the sex-linked Inverdale high prolificacy gene. Foundation animals for all breeds were screened on high litter size (lambs born, alive or dead, per ewe lambing) from industry flocks. Prior to being transferred to Woodlands between 1979 and 1984, their average litter size was 2·66. Ovulation rates for descendants of the foundation ewes averaged 2·15 (Romney), 2·43 (Coopworth), 2·15 (Perendale) and 2·96 for the Romney subgroup carrying the Inverdale gene. Embryo survival averaged 0·84 except for a low value in Inverdales (0·76). Using a restricted maximum likelihood model, with full relationship matrix, the within-breed heritability of ovulation rate over all ages and breeds (excluding Inverdale) was 0·14 (s.e. 0·03), with repeatability 0·26 (s.e. 0·02). Litter size averaged 1-80 (Romney), 2·05 (Coopworth), 1·76 (Perendale) and 2·17 (Inverdale). The heritability estimate for litter size (excluding Inverdale) was 0·073 (s.e. 0·018), from data for all ages. The genetic correlation between ovulation rate and litter size was 0·91 (s.e. 0·08). The standard deviation for ovulation rate in the Inverdales was 1·75 times as great as the average of the other three breeds. Embryo survival to term for ewes conceiving to two, three or four ovulations averaged 0·89, 0·77 and 0·64, respectively, and was significantly different among breeds fP < 0·001). The greater ovulation rate in Inverdales than Romneys was sufficient to explain the Inverdale effect on reduced embryo survival. The highest embryo survival was observed in the Coopworth breed (P < 0·001).

Keywords

embryo mortalitylitter sizeovulation ratesheep
Type
Research Article
Information
Animal Science , Volume 67 , Issue 2 , October 1998 , pp. 289 - 297
Copyright
Copyright © British Society of Animal Science 1998

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References

Clarke, J. N. 1978. Romneys: highly selected versus industry control animals. Proceedings of the Ruakura farmers' conference. Farm production and practice notes no. 160. New Zealand Ministry of Agriculture and Fisheries, PO Box 2298, Wellington.Google Scholar
Davis, G. H., Dodds, K. G., McEwan, J. C. and Fennessy, P. F. 1993. Liveweight fleece weight and prolificacy of Romney ewes carrying the Inverdale prolificacy gene (FecX1) located on the X-chromosome. Livestock Production Science 34: 83–91.CrossRefGoogle Scholar
Davis, G. H., McEwan, J. C., Fennessy, P. F., Dodds, K. G. and Farquhar, P. A. 1991. Evidence for the presence of a major gene influencing ovulation rate on the × chromosome of sheep. Biology of Reproduction 44:620–624.Google Scholar
Davis, G. H., McEwan, J. C., Fennessy, P. F., Dodds, K. G., McNatty, K. P. and O, W. S. 1992. Infertility due to bilateral ovarian hypoplasia in sheep homozygous (FecX1 FecX1) for the Inverdale prolificacy gene located on the × chromosome. Biology of Reproduction 46: 636–640.CrossRefGoogle Scholar
Davis, G. H., McEwan, J. C., Howarth, M. V., Kelly, R. W. and Paterson, A. T. 1987. Reproductive performance of progeny of prolific Romney, Coopworth and Perendale sheep. Proceedings of the New Zealand Society of Animal Production 47:89–91.Google Scholar
Dodds, K. G., Davis, G. H., Elsen, J. M., Isaacs, K. L. and Owens, J. L. 1991. The effect of Booroola genotype on some reproductive traits in a Booroola Merino flock. In Major genes for reproduction in sheep (ed. Elsen, J. M., Bodin, L. and Thimonier, J.), pp. 359–366. INRA, Paris.Google Scholar
Gilmour, A. R. 1997. ASREML for testing fixed effects and estimating multiple trait variance components. Proceedings of the Association for the Advancement of Animal Breeding and Genetics 12: 386–390.Google Scholar
Hanrahan, J. P. 1980. Ovulation rate as the selection criterion for litter size in sheep. Proceedings of the Australian Society of Animal Production 13:405–408.Google Scholar
Hanrahan, J. P. and Quirke, J. F. 1985. Contribution of variation in ovulation rate and embryo survival to within-breed variation in litter size. In Genetics of reproduction in sheep (ed. Land, R. B. and Robinson, D. W.), pp. 193–201. Butterworths, London.Google Scholar
Johnson, D. L. and Thompson, R. 1995. Restricted maximum likelihood estimation of variance components for univariate animal models using sparse matrix techniques and average information. Journal of Dairy Science 78: 449–456.Google Scholar
Kelly, R. W. 1982. Reproductive performance of commercial sheep flocks in South Island districts. 1. Flock performance and sources of wastage between joining and tailing. New Zealand Journal of Agricultural Research 25: 175–183.Google Scholar
Kelly, R. W., Lewer, R. P., Allison, A. J., Paterson, A. T. and Howarth, M. V. 1983. Techniques to establish flocks from fecund ewes by superovulation with and without ova transfer. Proceedings of the New Zealand Society of Animal Production 43:205–208.Google Scholar
Land, R. B., Atkins, K. D. and Roberts, R. C. 1983. Genetic improvement of reproductive performance. In Sheep production (ed. Haresign, W.), pp. 515–535. Butterworths, London.Google Scholar
Lawes Agricultural Trust. 1994. Statistical package: Genstat 5, release 3.1. Lawes Agricultural Trust, Rothamsted Experimental Station, UK.Google Scholar
McEwan, J. C., Davis, G. H., Dodds, K. G., Fennessy, P. F., Clarke, J. N., Bruce, G. D. and Hishon, M. G. 1992. Comparison of growth, hogget fleece weight and reproductive traits of three sheep breeds from a flock selected for prolificacy and a Romney control flock. Proceedings of the New Zealand Society of Animal Production 52:211–215.Google Scholar
Meyer, H. H. 1985. Breed differences in ovulation rate and uterine efficiency and their contribution to fecundity. In Genetics of reproduction in sheep (ed. Land, R. B. and Robinson, D. W.), pp. 185–191. Butterworths, London.Google Scholar
Meyer, H. H. and Clarke, J. N. 1982. Effect of ewe ovulation rate and uterine efficiency on breed and strain variation in litter size. Proceedings of the New Zealand Society of Animal Production 42:33–35.Google Scholar
Meyer, H. H., Clarke, J. N., Harvey, T. G. and Malthus, I. C. 1983. Genetic variation in uterine efficiency and differential responses to increased ovulation rate in sheep. Proceedings of the New Zealand Society of Animal Production 43:201–204.Google Scholar
Morris, C. A. 1990. Theoretical and realised responses to selection for reproductive rate. Proceedings of the fourth world congress on genetics applied to livestock production, Edinburgh, vol. 16, pp. 309–318.Google Scholar
Morris, C. A., Towers, N. R., Wesselink, C. and Southey, B. R. 1991. Effects of facial eczema on ewe reproduction and postnatal lamb survival in Romney sheep. New Zealand Journal of Agricultural Research 34:407–412.Google Scholar
Nicholas, F. W. 1996. In Introduction to veterinary genetics. Oxford University Press, Oxford.Google Scholar
Piper, L. R., Bindon, B. M., Atkins, K. D. and Rogan, I. M. 1984. Ovulation rate as a selection criterion for improving litter size in Merino sheep. In Reproduction in sheep (ed. Lindsay, D. R. and Pearce, D. T.), pp. 237–239. Australian Academy of Science, Canberra.Google Scholar