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