Evaluation of Bos indicus and Bos taurus straightbreds and crosses, 3. Direct and maternal genetic effects on growth traits [beef cattle]
1994
Arthur, P.F. | Hearnshaw, H. | Kohun, P.J. | Barlow, R. (New South Wales Agriculture, Grafton (Australia). Agricultural Research and Advisory Station)
Data on Brahman and Hereford cattle and their crosses were used to estimate direct additive, direct heterosis, maternal additive and maternal heterosis effects for pre-weaning and post-weaning liveweights, average daily gain (ADG) and height at various ages. The cattle were raised on high, medium and low quality pastures until weaning. Direct heterosis was significant for most traits. Estimates of direct heterosis for weaning weight were 24.9 and 20.2 kg, and for pre-weaning ADG were 79 and 68 g per day, on high and medium quality pastures respectively. Direct heterosis for ADG of steers (weaning to 36 months) and heifers (weaning to 30 months) was 91 and 76 g per day respectively. Estimates of maternal heterosis for weaning weights were 14.9, 30.9 and 37.8 kg and for pre-weaning ADG were 31 (not significant), 105 and 153 g per day, for high and medium and low quality pastures respectively. Maternal heterosis for ADG of steers (weaning to 36 months) was minus 47 g per day. There was a negative direct additive effect on post-weaning ADG in environments where pasture quality was good, but the effect was not significant on poor quality pasture. Maternal additive effect was negative for birth weight for high and medium quality pastures and positive for weaning weight and pre-weaning ADG on low quality pasture.
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