Growth and carcass characteristics of Angus, Brahman and Piedmontese sired progeny : results from the first calf crop.

SUMMARY The effects of Angus (A), Brahman (B) or Piedmontese (P) sires on growth and carcass traits in progeny from mature Bos indicus and Bos tuurus dams were examined using 120 heifers and steers. Pre-weaning, calves were grazed on sub-tropical pastures at Grafton. After weaning they were transferred to temperate pastures in Northern NSW, before being finished either in a feedlot, or at pasture, and slaughtered at 21 months of age for the Korean market. The mean birth weight was 35.1 kg and calving difficulty 3%; neither trait was affected by sire breed. Relative to B sired progeny, A and P sired progeny from Bos indicus content dams grew faster to weaning (897, 1038, and 984, g/d, for B, A and P, respectively) and were heavier at weaning (231, 262 and 252 kg); whereas A sired progeny from Bos tuurus dams, ranked lowest for preweaning growth (838 for A vs 903 for P and 868 g/d for B). Postweaning, A sired progeny grew fastest from 10 to 15 months of age, when growth rates were low (160 g/d), and also during feedlot finishing when growth rates were high (1465 g/d). However, from 15 to 18 months of age, when growth rates of cattle on pasture were high (926 g/d), or when heifers were fmished on pasture (630 g/d), sire breed did not significantly affect growth rates. At slaughter, A sired progeny were heaviest (505 kg) and B sired progeny lightest (458 kg). Piedmontese sired cattle had greater dressing percent (56.6%) than A or B sired cattle (54.5%), which resulted in A and P sired carcasses being heavier than B sired carcasses. For feedlot finished cattle, Piedmontese sired carcasses had 23% larger eye muscle area and 2.3% more saleable meat yield. Angus sired carcasses were fattest (18 mm) with most marbling (4.1% lipid) and P sired carcasses were leanest (9 mm) with least marbling (2.2% lipid).