GENETIC PARAMETERS, SIRE EVALUATION AND GENETIC TREND FOR PREWEANING GROWTH TRAITS IN FRIESIAN CALVES IN EGYPT | ||
| Journal of Animal and Poultry Production | ||
| Article 11, Volume 27, Issue 2, February 2002, Pages 911-926 PDF (6.64 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jappmu.2002.253341 | ||
| Author | ||
| E. Z. M. Oudah, | ||
| Animal Production Department, Faculty of Agriculture, Mansoura University, PC 35516, Egypt. | ||
| Abstract | ||
| Records of birth weight (BWT) and weaning weight 0NWT) of 1184 Friesian calves (593 males and 591 females) progeny of 49 sires and 489 dams born during the period from 1990 to 2000 were used in the present study. The average number of calves per sire was 18.3. Data were statistically analyzed using the least squares mixed model and maximum likelihood (LSMLMW) computer program of Harvey (1990). The effects of sire (random effect), year and season of birth, sex of calf (fixed effects) and dam weight at calving (OWe) (covariate) for analysing BWT, WWT and average daily gain (ADG) from birth to weaning were studied. Both BWT and age of calf at weaning (suckling period) (SP) were included in the model as linear covariates when analyzing WWT and ADG. The least squares means (± SE) of BWT, \N'oN[ and ADG were 31.3±0.33, 97.0±0.75 kg and 624±C1..72 g/tj, respectively. Sire, year of calving, sex of calf, owe and am ha~ lhiglilLyl sfgnifieant (P<0.001) effects on traits' studied. Season of birth sh.lO.w.edl higJnLW signifieamt (P<O.Ot). effect only on BWT. Birth weight and! 'W'NF increased! byr 0.021 and 0\018 kg/kg increase in owe, respectively. Weaning weig,litt of caNes increased by, 0.36 kg per each kg lncrease illt Swt. Meanwhile, ADG decreased by -6.1'~ gtd per each kg increase in BWT. Calves born in spring were the heavier BWT and those born in autumn were the lower BWT (32.0 vs. 30.6 kg). The proportions of sire variance components (82s) for BWT, WWT and ADG were 6.03, 6.96 and 7.04%, respectively. Heritability estimates were 0.241, 0.279 and 0.281, respectively. The genetic, phenotypic and environmental correlation coefficients among studied traits generally were low and positive except the correlations between WWT and ADG were strong (0.907, 0.892 and 0.886, respectively) and between BWT and ADG were moderate and negative (-0.285, - 0.278 and -0.277, respectively). Estimates of sire-transmitting ability (ETA's) as deviations from the overall means using Best Linear Unbiased Prediction (BLUP) method ranged from -0.856 to +2.24 kg for BWT, from -3.86 to +4.46 kg for WWT and from -36.4 to +42.3 g/d for ADG. Percentages of sires that had positive ETA estimates for studied traits ranged from 43.24 to 48.65%. Spearman rank correlation coefficients among ETA's of BWT and both WWT and ADG were low and negative (- 0.17 and -0.17, respectively), while the corresponding correlation between WWT and ADG was high and positive (0.998). The annual phenotypic and genetic trends in BWT were positive and significant (0.149 and 0.503 kg/year, respectively). Meanwhile, the phenotypic trends in both WWT and ADG were negative and significant (-0.268 kg/year and -2.55 g/d/year in the two traits, respectively) and the genetic trends in the same two traits were negative also (~0.060 kg/year and -0.615 . g/d/year, respectively) but not significant. From this study, it could be concluded that the economic importance must be given to growth traits in breeding programs. | ||
| Keywords | ||
| Friesian calves; growth traits; sire evaluation; genetic trend; Egypt | ||
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