| dc.description.abstract | Maternal influence on growth of artificially reared Sahiwal cattle was investigated using data from the National
Sahiwal Stud (NSS). Growth records on animals born from 1973 to 2004 were used for the analysis. The traits
considered were; birth weight (BW, kg), weaning age at 42kg weight (WA1, days), weaning age at 55 kg
weight (WA2, days), weaning age of all animals weaned at 42 kg and 55 kg combined (WA, days), branding
age at 130 kg (BA, days), preweaning daily gain to WA1 (DG1, g/day), preweaning daily gain to WA2 (DG2,
g/day), preweaning gain from combined data (DG, g/day), post weaning daily gain to BA (PDG, g/day) and
average daily gain from birth to BA (ADG, g/day). Maternal effects were important for BW but low to almost
absent for pre- and post weaning traits. Ignoring maternal effects substantially increased the direct additive
genetic variance and hence direct heritability estimates. Fitting maternal effects reduced direct heritability from
0.34 to 0.15 for BW. Genetic correlations between direct and maternal effects were positive and high for BW
(0.66 and 0.72). The low and absence of maternal effects on pre- and post weaning traits shows that
improvement in these traits would be more efficiently achieved if selection was based on the animal’s direct
genetic potential. The influence of maternal effects on BW of artificially reared Sahiwal cattle indicates that
inclusion of these effects in analysis of BW will result in accurate parameter estimates which would improve
selection efficiency. | en_US |
