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Estimates of (co)variances due to direct and maternal effects for body weights in Timahdite sheep

Published online by Cambridge University Press:  18 August 2016

I. Boujenane  and
J. Kansari
I. Boujenane*
Affiliation:
Department of Animal Production, Institut Agronomique et Vétérinaire Hassan II, BP 6202 Rabat-Instituts, 10101 Rabat, Morocco
J. Kansari
Affiliation:
Société Nationale de Développement de l'Elevage, 5 Rue de Salé, Tour Hassan, Rabat, Morocco
*
† Corresponding author E-mail:[email protected]
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Abstract

Genetic parameters for body weights in Timahdite sheep were estimated using records of 10370 lambs from the ‘Société Nationale de Développement de l’Elevage’ born in 1988-89 to 1998-99. An animal model with derivativefree restricted maximum likelihood procedures was used. Random effects were direct and maternal additive genetic, maternal permanent environmental, and error. Direct and maternal heritability estimates were 0·05 and 0·05 for birth weight, 0·02 and 0·07 for weight at 30 days, 0·07 and 0·08 for weight at 70 days, 0·06 and 0·01 for weight at 90 days. Estimates of fraction of variance due to maternal permanent environmental effects were close to zero, except for weight at 90 days. Genetic correlations between direct and maternal genetic effects were –0·55, –0·51, –0·50 and –0·17 for body weights at birth, 30, 70 and 90 days, respectively. Estimates of direct genetic correlations among body weights were positive and high, ranging from 0·69 to unity. Phenotypic correlations were positive and moderate to high, being lower than their corresponding direct genetic correlations. Estimates of correlations between maternal genetic effects among weights were positive and high, varying from 0·79 to unity. Cross-correlations between direct genetic effects for one weight and maternal genetic effects for another weight were consistently negative, ranging from –0·05 to –0·63. These results indicate that selecting for improved maternal and/or direct effects in Timahdite sheep is expected to generate only slow genetic progress in terms of early growth.

Keywords

body weightcorrelationheritabilitymaternal effectssheep
Type
Breeding and genetics
Information
Animal Science , Volume 74 , Issue 3 , June 2002 , pp. 409 - 414
Copyright
Copyright © British Society of Animal Science 2002

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References

Al-Shorepy, S. A., 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.CrossRefGoogle Scholar
Analla, M., Munoz-Serrano, A., Cruz, J. M. and Serradilla, J. M., 1995. Estimation of genetic parameters of growth traits in Segureña lambs. Journal of Animal Breeding and Genetics 112: 183–190.CrossRefGoogle Scholar
Boldman, K. G., Kriese, L. A., Van Vleck, L. D., Van Tassell, C. P., and Kachman, S. D., 1995. A manual for use of MTDFREML. A set of programs to obtain estimates of variancesand covariances USDA, ARS, Washington, DC.Google Scholar
Boujenane, I. and Kerfal, M. 1990. Estimates of genetic and phenotypic parameters for growth traits of D’man lambs. Animal Production 51: 173–178.Google Scholar
Boujenane, I. and Mharchi, A. 1992. Estimation des paramètres génétiques et phénotypiques des performances de croissance et de viabilité des agneaux de race Beni Guil. Actes de l’Institut Agronomique et Vétérinaire Hassan II 12: 15–22.Google Scholar
El Fadili, M., Michaux, C., Boulanouar, B. and Leroy, P. L. 2000a. Environmental and genetic effects on growth in Timahdite and crossbred lambs in Morocco. Revue d’Elevageet de Médicine Vétérinaire des Pays Tropicaux 53: 75–83.Google Scholar
El Fadili, M., Michaux, C., Boulanouar, B. and Leroy, P. L. 2000b. Genetic parameters for growth traits of the Moroccan Timahdit breed of sheep. Small Ruminant Research 37: 203–208.CrossRefGoogle Scholar
Hagger, C. 1998. Litter, permanent environmental, ramflock, and genetic effects on early weight gain of lambs. Journal of Animal Science 76: 452–457.CrossRefGoogle ScholarPubMed
Maria, G. A., Boldman, K. G. and Van Vleck, L. D. 1993. Estimates of variances due to direct and maternal effects for growth traits of Romanov Sheep. Journal of Animal Science 71: 845–849.CrossRefGoogle ScholarPubMed
Mousa, E., Van Vleck, L. D., and Leymaster, K. A. 1999. Genetic parameters for growth traits for a composite terminal sire breed of sheep. Journal of Animal Science 77: 1659–1665. Google Scholar
Näsholm, A. and Danell, Ö. 1996. Genetic relationships of lamb weight, maternal ability, and mature ewe weight in Swedish finewool sheep. Journal of Animal Science 74: 329–339.CrossRefGoogle ScholarPubMed
Notter, D. R. 1998. Genetic parameters for growth traits in Suffolk and Polypay sheep. Livestock Production Science 55: 205–213.Google Scholar
Tijani, A. and Boujenane, I. 1993. Estimation des paramètres génétiques et phénotypiques des performances de croissance des agneaux de race Timahdite au Maroc. Forty-fourth annual meeting of the European Association for Animal Production, Aarhus, Denmark.Google Scholar
Tosh, E. and Kemp, R. A. 1994. Estimation of variance components for lamb weights in three sheep populations. Journal of Animal Science 72: 1184–1190.CrossRefGoogle ScholarPubMed
Vaez Torshizi, R., Nicholas, F. W. and Raadsma, H. W. 1996. REML estimates of variance and covariance components for production traits in Australian Merino sheep, using an animal model. 1. Body weight from birth to 22 months. AustralianJournal of Agricultural Research 47: 1235–1249.CrossRefGoogle Scholar
Willham, R. L. 1972. The role of maternal effects in animal breeding. III. Biometrical aspects of maternal effects in animals. Journal of Animal Science 35: 1288–1293.CrossRefGoogle Scholar
Yazdi, M. H., Engström, G., Näsholm, A., Johansson, K., Jorjani, H. and Liljedahl, L. -E. 1997. Genetic parameters for lamb weight at different ages and wool production in Baluchi sheep. Animal Science 65: 247–255.CrossRefGoogle Scholar