Abstract
Genetic and phenotypic parameters were estimated for lamb growth traits for the Dorper sheep in semi-arid Kenya using an animal model. Data on lamb growth performance were extracted from available performance records at the Sheep and Goats Station in Naivasha, Kenya. Growth traits considered were body weights at birth (BW0, kg), at 1 month (BW1, kg), at 2 months (BW2, kg), at weaning (WW, kg), at 6 months (BW6, kg), at 9 months (BW9, kg) and at yearling (YW, kg), average daily gain from birth to 6 months (ADG0–6, gm) and from 6 months to 1 year (ADG6–12, gm). Direct heritability estimates were, correspondingly, 0.18, 0.36, 0.32, 0.28, 0.21, 0.14, 0.29, 0.12 and 0.30 for BW0, BW1, BW2, WW, BW6, BW9, YW, ADG0–6 and ADG6–12. The corresponding maternal genetic heritability estimates for body weights up to 9 months were 0.16, 0.10, 0.10, 0.19, 0.21 and 0.18. Direct-maternal genetic correlations were negative and high ranging between −0.47 to −0.94. Negative genetic correlations were observed for ADG0–6–ADG6–12, BW2–ADG6–12, WW–ADG6–12 and BW6–ADG6–12. Phenotypic correlations ranged from 0.15 to 0.96. Maternal effects are important in the growth performance of the Dorper sheep though a negative correlation exists between direct and maternal genetic effects. The current study has provided important information on the extent of additive genetic variation in the existing flocks that could now be used in determining the merit of breeding rams and ewes for sale to the commercial flocks. The estimates provided would form the basis of designing breeding schemes for the Dorper sheep in Kenya. Implications of the study to future Dorper sheep breeding programmes are also discussed.
Similar content being viewed by others
References
Abegaz, S., Negussie, E., Duguma, G. and Rege, J.E.O., 2002. Genetic parameter estimates for growth traits in Horro sheep. Journal of Animal Breeding and Genetic, 119, 35–45.
Al-Shorepy, S.A., 2001. Genetic parameters for growth traits of a local breed of sheep in the United Arab Emirates. Journal of Agricultural Science, 137, 365–371.
Boldman, K.G., Kriese, L.A., Van Vleck, L.D., Van Tassel, C.P. and Kachman, S.D., 1995. A Manual for the Use of MTDFREML. A Set of Programs to Obtain Estimates of Variances and Covariances [Draft]. ARS-USDA, Clay Center, NE.
Gicheha, M.G., Kosgey, I.S., Bebe, B.O. and Kahi, A.K., 2006. Evaluation of the efficiency of alternative two-tier nucleus breeding systems designed to improve meat sheep in Kenya. Journal of Animal Breeding and Genetics, 123, 247–257.
Gizaw, S., Lemma, S., Komen, H. and Van Arendonk, J.A.M., 2007. Estimates of genetic parameters and genetic trends for live weight and fleece traits in Menz sheep. Small Ruminant Research, 70, 145–153.
Inyangala, B.A.O., Rege, J.E.O. and Itulya, S., 1992. Growth traits of the Dorper. II. Genetic and phenotypic parameters. In: Rey B, Lebbie S-H-B., Reynolds, L. (Eds). Small Ruminant Research and Development in Africa, Proceedings of the First Biennial Conference of the African Small Ruminant Network, 10–14 December, 1990, ILRAD, Nairobi, Kenya, pp 517–526.
Kiriro, P.M., 1994. Estimates of genetic and phenotypic parameters for the Dorper, Red Maasai and their crosses. In: Lebbie, S.B.H., Rey, B., Irungu, E.K. (Eds.), Small ruminant research and development in Africa, Proceedings of the Second Biennial Conference of the African Small Ruminant Research Network, 7–11 December, 1992, AICC, Arusha, Tanzania, pp. 229–234.
Kosgey, I.S., 2004. Breeding Objectives and Breeding Strategies for Small Ruminants in the Tropics. Ph.D Thesis, Wageningen University, The Netherlands, pp. 272.
Kosgey, I.S., van Arendonk, J.A.M. and Baker, R.L., 2003. Economic values for traits of meat sheep in medium to high potential areas of the tropics. Small Ruminant Research, 50, 187–202.
Kosgey, I.S., van Arendonk, J.A.M. and Baker, R.L., 2004. Economic values for traits in breeding objectives for sheep in the tropics: impact of tangible and intangible benefits. Livestock Production Science, 88, 143–160.
Kosgey, I.S., Baker, R.L., Udo, H.M.J. and van Arendonk, J.A.M., 2006. Successes and failures of small ruminant breeding programs in the tropics: a review. Small Ruminants Research, 61, 13–28.
Kosgey, I.S., Rowlands, G.L., Van Arendonk, J.A.M. and Baker, R.L., 2008. Small ruminant production in smallholder and pastoral/extensive farming systems in Kenya. Small Ruminant Research, 77, 11–24.
Maniatis, N. and Pollot, G.E., 2002. Nuclear, cytoplasmic, and environmental effects on growth, fat, and muscle traits in Suffolk lambs from sire referencing scheme. Journal of Animal Science, 80, 57–67.
Maniatis, N. and Pollot, G.E., 2003. The impact of data structure on genetic (co)variance components of early growth in sheep estimated using an animal model with maternal effects. Journal of Animal Science, 81, 101–108.
Meyer, K., 1997. Estimates of genetic parameters for weaning weight of beef cattle accounting for direct-maternal environmental covariances. Livestock Production Science, 50, 235–246.
Neser, F.W.C., Erasmus, G.J. and van Wyk, J.B., 2000. Genetic parameter estimates for pre-weaning growth traits in Dorper sheep. South Africa Journal of Animal Science, 30, 99–101.
Notter, D.R., 1998. Genetic parameters for growth traits in Suffolk and Polypay sheep. Livestock Production Science, 55, 205–213.
Rashidi, A., Mokhtari, M.S., Safi Jahanshahi, A., Mohammad and Abadi, M.R., 2008. Genetic parameter estimates of pre-weaning growth traits in Kermani sheep. Small Ruminant Research, 74, 165–171.
Rewe, T.O., Ogore, P.B. and Kahi, A.K., 2002. Integrated goat projects in Kenya: impact on genetic improvement. In: Proceedings of the Seventh World Congress on Genetics Applied to Livestock Production, vol. 33 19-23 August, 2002, Montpellier, France, pp. 385-387.
SAS 1998. The Statistical Analysis System. Version 8 for Windows. Cary, North Carolina, USA: SAS Institute Inc.
Vatankhah, M. and Talebi, M.A., 2008a. Genetic parameters of body weight and fat-tail measurements in lambs. Small Ruminants Research, 75, 1–6.
Vatankhah, M. and Talebi, M.A., 2008b. Heritability estimates and correlations between productions and reproductive traits in Lori-Bakhtiari sheep in Iran. South African Journal of Animal Science, 38, 110–118.
Zamani, P. And Mohammadi, H., 2008. Comparison of different models for estimation of genetic parameters of early growth traits in the Mehraban sheep. Journal of Animal Breeding and Genetics, 125, 29–34.
Acknowledgement
We thank the Sheep and Goat Station of the Ministry of Livestock Development for permission to use records from the station and Egerton University, Egerton, Kenya for provision of facilities.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kariuki, C.M., Ilatsia, E.D., Kosgey, I.S. et al. Direct and maternal (co)variance components, genetic parameters and annual trends for growth traits of Dorper sheep in semi-arid Kenya. Trop Anim Health Prod 42, 473–481 (2010). https://doi.org/10.1007/s11250-009-9446-0
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11250-009-9446-0