VARIANCE COMPONENTSDUE TO DIRECT AND MATERNAL EFFECTS AND ESTIMATION OF BREEDING VALUES FOR SOME GROWTH TRAITS OF EGYPTIAN BUFFALO CALVES . | ||
| Journal of Animal and Poultry Production | ||
| Article 12, Volume 30, Issue 12, December 2005, Pages 7425-7436 PDF (3.82 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jappmu.2005.238453 | ||
| Authors | ||
| H. G. EI-Awady,1; N. A. Shalaby2; Kawthar A. Mourad3 | ||
| 1Animal Prod. Dept., Fac. of Agric. Kafr .EI-Sheikh; Tanta Univ., Egypt. | ||
| 2Animal Prod. Dept., Fac. of Agric., Mansoura Univ., Egypt. | ||
| 3Animal Prod. Res. Inst., Ministry of Agric. and Land Recj., Dokki, Giza, Egypt. | ||
| Abstract | ||
| Data on growth traits from birth to weaning on 5405 Egyptian buffalo calves (2730 males and 2675 females) progeny of 1565 dams mating by 281 sires during the period from 1971 to 2001 at Mahallet Mousa farm was used in this study. Restricted Maximum Likelihood analysis method was used with animal model to estimate covariance components for birth weight (BW), weaning weight (WW) and daily gain (DG) from birth to weaning. Model included month and year of birth, birth sequence and sex of calf as fixed effects. Random effects were animal, direct and maternal genetic effect, maternal permanent environmental effect and residual effect. Weight of dam at calving was included in the model as covariate. Overall means and standard errors for BW, WW and DG were 33.4±6.4 kg, 86.7±11.2 kg and 503±107 g/day, respectively. Direct heritability (h2d) for BW, WW and DG were 0.35±0.03, 0.39±0.04 and 0.31±0.09, respectively. Corresponding maternal heritability (h2m) were O.19±0.01, 0.16±0.01 and 0.22±0.02, respectively. Total heritabilities (h2t) of the mentioned traits were 0.37, 0.38 and 0.38, respectively. Estimates of maternal permanent environmental variance as a proportion of phenotypic variance were 0.07, 0.04 and 0.21 for BW, WW and DG, respectively. Antagonism was observed between additive direct and maternal genetic effects and it were negative in all traits investigated, ranging from -0.65 to -0.08. Genetic and phenotypic correlations between BW and DG were small and negative, -0.19 and -0.34, respectively, while genetic and phenotypic correlations between WW and DG were high and positive, 0.82 and 0.91, respectively. Predicted breeding values (EBV's) of sires ranged from -2.3 to 2.6 kg for BW, -6.4 to 15.5 kg for WW and -79.9 to 116 g for DG. The (EBV's) for cows ranged from -4.8 to 3.4 kg, -15.8 to 9.7 kg and -131.7 to 99.4 g for the same traits, respectively. Similarly, predicted breeding values (EBV's) for dams ranged from -2.9 to 2.1 kg, -10.6 to 15.5 kg and -111.4 to 118 g, respectively for the above mentioned traits. Correlation coefficients between all traits studied were significant (P<0.05 or P<0.01), except correlation between BW and WW for sire breeding values were not significant. The correlations trends of predicted breeding values were in the same direction with those reported for genetic correlations of the same traits. The present results suggested that inclusion. maternal genetic effect and permanent environmental will provide a better chance for genetic improvement and higher accuracy of predicted breeding values than model without these components | ||
| Keywords | ||
| Growth traits; Egyptian buffalo calves; maternal effect; direct effect; direct heritability; maternal heritability; total heritability and direct-maternal genetic correlations | ||
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