Estimates of genetic parameters for growth traits in Kermani sheep
- 14 September 2007
- journal article
- Published by Wiley in Journal of Animal Breeding and Genetics
- Vol. 124 (5), 296-301
- https://doi.org/10.1111/j.1439-0388.2007.00672.x
Abstract
Birth weight (BW), weaning weight (WW), 6-month weight (W6), 9-month weight (W9) and yearling weight (YW) of Kermani lambs were used to estimate genetic parameters. The data were collected from Shahrbabak Sheep Breeding Research Station in Iran during the period of 1993–1998. The fixed effects in the model were lambing year, sex, type of birth and age of dam. Number of days between birth date and the date of obtaining measurement of each record was used as a covariate. Estimates of (co)variance components and genetic parameters were obtained by restricted maximum likelihood, using single and two-trait animal models. Based on the most appropriate fitted model, direct and maternal heritabilities of BW, WW, W6, W9 and YW were estimated to be 0.10 ± 0.06 and 0.27 ± 0.04, 0.22 ± 0.09 and 0.19 ± 0.05, 0.09 ± 0.06 and 0.25 ± 0.04, 0.13 ± 0.08 and 0.18 ± 0.05, and 0.14 ± 0.08 and 0.14 ± 0.06 respectively. Direct and maternal genetic correlations between the lamb weights varied between 0.66 and 0.99, and 0.11 and 0.99. The results showed that the maternal influence on lamb weights decreased with age at measurement. Ignoring maternal effects in the model caused overestimation of direct heritability. Maternal effects are significant sources of variation for growth traits and ignoring maternal effects in the model would cause inaccurate genetic evaluation of lambs.Keywords
This publication has 13 references indexed in Scilit:
- Genetic parameter estimates for pre-weaning weight traits in Dorper sheepSmall Ruminant Research, 2001
- Investigation of direct and maternal genetic effects on birth and weaning weight of Chios lambsLivestock Production Science, 2000
- Variance components due to direct and maternal effects and estimation of breeding values for 12-week weight of Welsh Mountain lambsAnimal Science, 1999
- Genetic relationships of lamb weight, maternal ability, and mature ewe weight in Swedish finewool sheep.Journal of Animal Science, 1996
- Direct and maternal (co) variance components and heritability estimates for body weight at different ages and fleece traits in Afrino sheepLivestock Production Science, 1995
- Estimates of variances due to direct and maternal effects for growth traits of Romanov sheep2Journal of Animal Science, 1993
- Variance components due to direct and maternal effects for growth traits of Australian beef cattleLivestock Production Science, 1992
- Genetic and environmental effects on growth to 1 year and viability of lambs from a crossbreeding study of D'man and Sardi breedsJournal of Animal Science, 1991
- The influence of maternal effects on the efficiency of selection; A reviewLivestock Production Science, 1981
- Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambsAnimal Science, 1980