The post-weaning growth of 281 Chianina x Hereford (CC.HH), Chianina x (Brahman x Hereford) (CC.BH), Brahman x Hereford (BB.H H), Hereford x (Brahman x Hereford) (H H.BH) and Hereford (HH.HH) steers grazing improved brigalow (Acacia harpophylla) country on a commercial property in southern Queensland was studied over 3 years. Representative animals were slaughtered at mean ages of about 880 and 1000 days and carcase characteristics examined. From weaning to 860 days of age, the CC.HH and CC.BH steers gained at a faster rate than the BB.HH steers, which in turn, grew faster than the HH.BH and HH.HH steers. Their growth rates were 0.58, 0.57, 0.55, 0.50 and 0.49 kg day-1, respectively. The CC.HH and the CC.BH steers dressed 309 kg with 6.5 mm fat and 308 kg with 7.0 mm fat, respectively. They were heavier (P< 0.05) and longer carcases with less fat and with larger eye muscle areas, than the other genotypes. The BB.HH and HH.BH carcases were intermediate, in terms of weight, being 291 kg and 278 kg, respectively, while the HH.HH carcases were lighter (P< 0.05) at 260 kg. The HH.HH carcases had similar fat cover to the HH.BH carcases, 9.6 mm vs 10.2 mm, and both had less fat cover than the BB.HH with 11.6 mm fat. Using the Australian Beef Carcases Appraisal System, the CC.HH and CC.BH carcases scored more points (P< 0.05) than all other genotypes.

Data relating to dystocia were obtained for 22% of beef herds in the Roma region of southern Queensland. In 1973 dystocia incidence in 23,129 maiden heifers was 12%; 4% of heifers and 7% of calves died. Thirty-five per cent of the 444 herds surveyed had more than a 10% incidence of dystocia, and 10% had more than a 30% incidence of dystocia. Only 6% of herds had no dystocia. Among the 73% of producers considering dystocia a problem in most years, 14% regarded it as a major problem. The incidence of dystocia in heifers was significantly higher in Poll Hereford than Hereford herds, which in turn were higher than other breeds of cattle. Poll Hereford and Hereford owners were the most concerned about dystocia but did not supervise calving more frequently. Dystocia and attitude were also examined in relation to degree of supervision at calving and size of the breeding herd.

The incidence of dystocias and the calving performance of primiparous Hereford heifers from 2 herds, one with a low (A) and the other a high (B) dystocia history, were compared when all animals were run on the same property in southern Queensland. The dystocia incidence was 21.4% for Herd A heifers and 40.5% for Herd B heifers (P approximately equal to 0.10). While Herd A heifers had significantly (P < 0.05) heavier calves than Herd B heifers (29.1 v 27.7 kg), the ratio of calf birth weight to dam pelvic brim area was 0.11 kg/cm2 for both groups. Differences in the size of the maternal pelvis, calf oversize and the type of presentation recorded for assisted births did not satisfactorily explain the difference in the incidence of dystocias. The circumstantial evidence indicated that inherent factors may affect dystocia.