| Abstrakt: |
Pre-weaning growth of 482 Angus, Charolais and Hereford sired progeny out of straightbred Hereford (H x H) , and first-cross Brahman x Hereford (B x H) , Simmental x Hereford (S x H) and Friesian x Hereford (F x H) dams was evaluated. The dams grazed either high, medium or low quality pasture (pre-weaning pasture system) at Grafton, NSW. Progeny of dams from high quality pre-weaning pasture were slaughtered at 281 days of age for the vealer market. The progeny of dams from medium and low quality pre-weaning pastures were evaluated for post-weaning growth on pasture, on commercial properties in temperate NSW. They were slaughtered for either the yearling domestic (both sexes) or heavy export steer markets. Average daily gain (ADG) for the entire pre-weaning period was greater (P < 0.05) for Charolais (845 g/day) than Angus (790 g/day) and Hereford (783 g/day) sired progeny. This resulted in a higher ( P < 0.05) weaning weight of Charolais sired progeny of dams on high or medium quality pre-weaning pasture. On low quality pasture, however, sire breed differences in weaning weight were not significant (P > 0.05). This indicates that adequate nutrition should be provided for Charolais sired progeny to express their higher growth potential. Post-weaning ADG of Charolais sired progeny was higher (P < 0.05) than that of Angus or Hereford sired progeny, resulting in 14 months liveweight (for yearling domestic cattle) of 370, 345 and 345 kg and 27 months liveweight (for heavy export steers) of 635, 585 and 569 kg for Charolais, Angus and Hereford sired progeny respectively. Progeny of B x H dams on medium or low quality pre-weaning pastures had the highest pre-weaning ADG and weaning weight, but the lowest post-weaning ADG. This resulted in 27 months liveweight of 558, 582, 628 and 616 kg for steer progeny from H x H, B x H, S x H and F x H dams respectively. |
