Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Genetic analysis of growth rate and Kleiber ratio in Zandi sheep


Genetic parameters for average daily gain from birth to weaning (ADGa), birth to 6 months (ADGb), weaning to 6 months (ADGc), weaning to yearling age (ADGd), and corresponding Kleiber ratios (KRa, KRb, KRc, and KRd) were estimated by using records of 3,533 Zandi lambs, descendent of 163 sires and 1265 dams, born between 1991 and 2005 at the Zandi Sheep Breeding Station at Khojir National Park, Tehran, Iran. A derivative-free algorithm combined with a series of six single-trait linear animal models was used to estimate phenotypic variance and its direct, maternal, and residual components. In addition, bivariate analyses were done to estimate (co)variance components between traits. Estimates of direct heritability (h 2) were 0.11, 0.15, 0.09, 0.10, 0.10, 0.10, 0.06, and 0.07 for ADGa, ADGb, ADGc, ADGd, KRa, KRb, KRc, and KRd, respectively, thereby indicating the presence of low additive genetic variation for growth rate and Kleiber ratio in this population of Zandi sheep. Maternal genetic component was found to be significant on ADGa and KRa and contributed 3% and 5%, respectively, in total phenotypic variance of ADGa and KRa. A widespread range of genetic correlations among traits studied was observed. Except for negative genetic correlations between ADGa and KRc, ADGa and KRd, and between KRa and KRc, in other cases, genetic correlations were positive and moderate to very high. Phenotypic correlations ranged from −0.49 (ADGa/KRd) to 0.94 (ADGc/KRc). These results indicate that selecting for improved growth rate or Kleiber ratio in Zandi sheep would generate a relatively slow genetic progress.

This is a preview of subscription content, log in to check access.


  1. Abegaz, S., van Wyk, J.B., Olivier, J.J., 2005. Model comparisons and genetic and environmental parameter estimates of growth and the Kleiber ratio in Horro sheep, South Aferican Journal of Animal Science, 35, 30–40.

  2. Arthur, P.F., Renand, G., Krauss, D., 2001. Genetic and phenotypic relationships among different measures of growth and feed efficiency in young Charolais bulls, Livestock Production Science, 68, 131–139.

  3. Bosso, N.A., Cisse, M.F., Van der Waaje, E.H., Fall, A., Van Arendonk, J.A.M., 2007. Genetic and phenotypic parameters of body weight in West African Dwarf goat and Djallonke sheep, Small Ruminant Research, 67, 271–278.

  4. 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.

  5. Dass, G., Singh, V.K., Ayub, M., 2004. Growth performance of Magra sheep under hot arid climate, Indian Journal of Animal Science, 74, 441–443.

  6. Ekiz, B., 2005. Estimates of maternal effects for pre-and post-weaning daily gain in Turkish merino lambs. Turkish Journal of Veterinary and Animal Science, 29, 399–407.

  7. Eskandarinasab, M.P., Ghafouri-Kesbi, F., Abbasi, M.A., 2010. Different models for evaluation of growth traits and Kleiber ratio in an experimental flock of Iranian fat-tailed Afshari sheep, Journal of Animal Breeding and Genetics, 127, 26–33.

  8. Gizaw, S., Joshi, K., 2004. Estimates of genetic parameters of growth traits in Menz and Awassi × Menz crossbred sheep in Ethiopia, Indian Journal of Animal Science, 74, 864–867.

  9. Ghafouri-Kesbi, F., Eskandarinasab, M.P., 2008. An evaluation of maternal influences on growth traits: the Zandi sheep breed of Iran as an example. Journal of Animal and Feed Sciences, 17, 519–529.

  10. Ghafouri-Kesbi, F., Eskandarinasab, M.P., Hassanabadi A., 2009. Short-term selection for yearling weight in a small-experimental Iranian Afshari sheep flock, Canadian Journal of Animal Science, 89, 301–307.

  11. Kalantar-Neyestanaki, M., 2004. Evaluation of some environmental effects on growth traits of Zandi sheep, Agriculture Research, 4, 49–58 (in Persian with English abstract).

  12. Kleiber, M., 1947. Body size and metabolic rate, Physiology Review, 27, 511– 541.

  13. Matika, O., Van Wyk, J.B., Erasmus, G.J., Baker R.L., 2003. Genetic parameter estimates in Sabi sheep. Livestock Production Science, 79, 17–28.

  14. 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, 67, 312–317.

  15. Meyer, K., 2000. Programs to estimate variance components for individual animal models by restricted maximum likelihood (REML). Ver .3.1. Users notes. Animal Genetics and Breeding Unit, University of New England, Armidale, NSW, Australia.

  16. Miraei-Ashtiani, S.R., Seyedalian, S.A.R., Moradi Shahrbabak, M., 2007. Variance components and heritabilities for body weight traits in Sangsari sheep, using univariate and multivariate animal models, Small Ruminant Research, 67, 271–278.

  17. NRC, National Research Council., 1985. Nutrient Requirements of Sheep, 6th rev. edn. National Academy Press, Washington, DC

  18. Rashidi A., Mokhtari M.S., Safi-Jahanshahi A., Mohammad-Abadi M.R., 2008. Genetic parameter estimates of pre-weaning growth traits in Kermani sheep, Small Ruminant Research, 74, 165–171.

  19. SAS, 2004. User’s Guide, version 9. SAS Institute, Cary NC

  20. Sinha, N.K., Singh, S.K., 1997. Genetic and phenotypic parameters of body weights, average daily gains and first shearing wool yield in Muzaffarnagri sheep. Small Ruminant Research, 26, 21–29.

  21. Tavakkolian, J., 1999. The Genetic Resources of Native Farm Animals of Iran. Animal Science Research Institute of Iran Press, Karaj.

Download references


The staff of the Zandi Sheep Breeding Station who provided the raw data is gratefully acknowledged. Thanks are also extended to two anonymous reviewers for their valuable comments on a previous version of this manuscript.

Author information

Correspondence to Farhad Ghafouri-Kesbi.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ghafouri-Kesbi, F., Abbasi, M.A., Afraz, F. et al. Genetic analysis of growth rate and Kleiber ratio in Zandi sheep. Trop Anim Health Prod 43, 1153 (2011).

Download citation


  • Sheep
  • Average daily gain
  • Kleiber ratio
  • Animal model
  • Heritability