Genetic correlations between ewe reproductive and lamb weight traits in D’man sheep

Document Type : Original Research Article (Regular Paper)

Authors

1 Department of Animal Production and Biotechnology, Hassan II Institute of Agronomy and Veterinary Medicine, Rabat, Morocco

2 Centre Régional de la Recherche Agronomique d’Errachidia, Institut National de la Recherche Agronomique, Errachidia, Morocco

Abstract

The objective of this study was to estimate genetic, phenotypic and residual correlations between ewe reproductive and lamb weight traits in D’man sheep. Data used in this study were 1804 reproductive and weight records collected between 1988 and 2015 from 530 replacement females, born from 82 sires and 298 dams. The ewe reproductive traits included litter size and litter weight at birth (LSB and LWB) and at 90 days (LSW and LWW) per ewe lambing and mating weight (MW), while the lamb weight traits investigated were weights at birth (BW), 90 (WW) and 135 (W135) days. Covariance components between the reproductive traits on the one hand and the weight traits on the other hand were estimated using bivariate analyses by employing the animal model that was deemed to be most appropriate from the univariate analyses for each trait. The genetic correlations between litter traits and body weights were low and in general not significantly different from zero ranging from -0.12 to 0.11, whereas those between ewe MW and lamb weights were positive and moderate varying from 0.16 to 0.51. The corresponding phenotypic correlations were slightly lower and varied from -0.04 between LSW and WW to 0.12 between LWW and BW and between LSW and W135. The residual correlations were in general similar to genetic correlations, except those between MW and body weights that were lower. It was concluded that selection for a genetic improvement in either of reproductive and weight traits would have little effect on genetic response in the other trait.

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References

References
Afolayan, R.A., Fogarty, N.M., Gilmour, A.R., Ingham, V.M., Gaunt, G.M., Cummins, L.J., 2009. Genetic correlations between early growth and wool production of crossbred ewes and their subsequent reproduction. Animal Production Science 49, 17-23.
Boldman, K.G., Kriese, L.A., Van Vleck, L.D., Van Tassell, C.P., Kachman, S.D., 1995. A manual for use of MTDFREML. In: A Set of Programs to Obtain Estimates of Variances and Covariances. USDA/ARS, Washington, DC, USA (Draft).
Borg, R.C., Notter, D.R., Kott, R.W., 2009. Phenotypic and genetic associations between lamb growth traits and adult ewe body weights in western range sheep. Journal Animal Science 87, 3506-3514.
Boujenane, I., 1996. The D'man. In: Fahmy, M.H. (Ed.) "Prolific Sheep”. CAB International, Wallingford, UK, pp. 109‑120.
Boujenane, I., 2006. Reproduction and production performance of Moroccan sheep breeds. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 1, N° 014, 18 pp.
Boujenane, I., Kerfal, M., 1990. Estimates of genetic and phenotypic parameters for growth traits of D'man lambs. Animal Production 51, 173‑178.
Boujenane, I., Chikhi, A., Ibnelbachyr, M., Mouh, F.Z., 2015. Estimation of genetic parameters and maternal effects for body weight at different ages in D’man sheep. Small Ruminant Research 130, 27-35.
Boujenane, I., Chikhi, A., Sylla, M., Ibnelbachyr, M., 2013. Estimation of genetic parameters and genetic gains for reproductive traits and body weight of D’man ewes. Small Ruminant Research 113, 40-46.
Boujenane, I., Kerfal, M., Khallouk, M., 1991. Genetic and phenotypic parameters for litter traits of D'man ewes. Animal Production 52, 127‑132.
Bromley, C.M., Snowder, G.D., Van Vleck, L.D., 2000. Genetic parameters among weight, prolificacy, and wool traits of Columbia, Polypay, Rambouillet, and Targhee sheep. Journal of Animal Science 78, 846-858.
Bromley, C.M., Van Vleck, L.D., Snowder, G.D., 2001. Genetic correlations for litter weight weaned with growth, prolificacy, and wool traits in Columbia, Polypay, Rambouillet, and Targhee sheep. Journal of Animal Science 79, 339-346.
Hanford, K.J., Van Vleck, L.D., Snowder, G.D., 2002. Estimates of genetic parameters and genetic change for reproduction, weight, and wool characteristics of Columbia sheep. Journal of Animal Science 80, 3086-3098.
Hanford, K.J., Van Vleck, L.D., Snowder, G.D., 2003. Estimates of genetic parameters and genetic change for reproduction, weight, and wool characteristics of Targhee sheep. Journal of Animal Science 81, 630-640.
Hanford, K.J., Van Vleck, L.D., Snowder, G.D., 2005. Estimates of genetic parameters and genetic change for reproduction, weight, and wool characteristics of Rambouillet sheep. Small Ruminant Research 57, 175-186.
Hanford, K.J., Van Vleck, L.D., Snowder, G.D., 2006. Estimates of genetic parameters and genetic trend for reproduction, weight, and wool characteristics of Polypay sheep. Livestock Science 102, 72-82.
Heydarpour, M., Schaeffer, L.R., Yazdi, M.H., 2008. Influence of population structure on estimates of direct and maternal parameters. Journal of Animal Breeding and Genetics 125, 89-99.
Maniatis, N., Pollott, 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.
Maxa, J., Norberg, E., Berg, P., Pedersen, J., 2007. Genetic parameters for growth traits and litter size in Danish Texel, Shropshire, Oxford Down and Suffolk. Small Ruminant Research 68, 312-317.
Mohammadi, H., Moradi Shahrebabak, M., Moradi Shahrebabak, H., 2013. Analysis of genetic relationship between reproductive vs. lamb growth traits in Makooei ewes. Journal of Agriculture Science and Technologies 15, 45-53.
Mohammadi, K., Taghi Beigi Nassiri, M., Rahmatnejad, E., Abdollahi-Arpanahi, R., Hossaini, S. M.R., Hagh Nadar, S., 2014. Genetic correlations between growth and reproductive traits in Zandi sheep. Tropical Animal Health and Production 46, 895-899.
Notter, D.R., Ngere, L., Burke, J.M., Miller, J.E., Morgan, J.L.M., 2018. Genetic parameters for ewe reproductive performance and peri-parturient fecal egg counts and their genetic relationships with lamb body weights and fecal egg counts in Katahdin sheep. Journal of Animal Science 96, 1579-1589.
Rao, S., Notter, D.R., 2000. Genetic analysis of litter size in Targhee, Suffolk, and Polypay sheep. Journal of Animal Science 78, 2113-2120.
Safari, E., Fogarty, N.M., Gilmour, A.R., 2005. A review of genetic parameter estimates for wool, growth, meat and reproduction traits in sheep. Livestock Production Science 92, 271-289.
SAS Institute, 2002. SAS User’s Guide Version 9.2: Statistics. Cary, NC: SAS Institute Inc.
Snyman, M.A., Cloete, S.W.P., Oliver, J.J., 1998. Genetic and phenotypic correlations of total weight of lamb weaned with body weight, clean fleece weight and mean fibre diameter in three South African Merino flocks. Livestock Production Science 55, 157-162.
Vatankhah, M., Talebi, M.A., 2008. Heritability estimates and correlations between production and reproductive traits in Lori-Bakhtiari sheep in Iran. South African Journal of Animal Science 38, 110-118.
Zishiri, O.T., Cloete, S.W.P., Olivier, J.J., Dzamaa, K., 2013. Genetic parameters for growth, reproduction and fitness traits in the South African Dorper sheep breed. Small Ruminant Research 112, 39-48.
Journal of Livestock Science and Technologies
Volume 9, Issue 2
December 2021
Pages 41-49

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