Post-weaning growth of cattle in northern New South Wales. 2. Growth pathways of steers

Abstract

Abstract. This paper describes the post-weaning growth of Bos taurus and Bos taurus × Bos indicus-derived steers grazing temperate perennial pasture in northern New South Wales. These cattle were either autumn weaners from spring-calving herds in summer rainfall environments, or summer weaners from autumn-calving herds in winter rainfall environments. Autumn weaners were grown out on 3 pasture systems: (i) pasture only (P1), (ii) pasture supplemented in late winter-early spring with formulated pellets of high protein content (P2), or (iii) pasture supplemented with a nitrogen-fertilised forage crop (P3) to provide different growth pathways towards entry to the finishing phase. Over the 3-year study, seasonal liveweight gain on P1 varied between -0.21 and 1.05 kg/head.day; liveweight gain was generally low (about 0.5 kg/head.day) in winter and high (about 0.8 kg/head.day) in spring. Bos taurus autumn weaners achieved feedlot entry specifications for the domestic market (300 kg liveweight) in 6-8 weeks by the end of winter, and feedlot entry specifications for the export market (400 kg liveweight) in 17-27 weeks by the end of summer. For B. taurus × B. indicus-derived autumn weaners, the period to feedlot entry was 19 and 33 weeks for domestic and export feedlot entry specifications, respectively. Supplementary feeding generally increased post-weaning growth in late winter-early spring and reduced the period to feedlot entry for export steers. Summer weaners were grown out on pasture in P1, P2 or P3 pasture systems, met domestic feedlot entry specifications on arrival, but did not reach export feedlot entry specifications before the onset of winter imposed liveweight stasis. The most effective grow-out system was based on Bos taurus autumn weaners with supplementary feeding in winter-spring to overcome the limitations of the winter feed gap.

Calves Weaned and Backgrounded on Pasture Respond to Pasture Nutritive Value and Supplements

“…Dicker et al (1) demonstrated that supplementing steers backgrounded on pasture generally increases post‐weaning ADG (1.14 vs. 1.69 lb) and reduces the period to feedlot entry compared to steers backgrounded on pasture without supplement. Our study provided similar results since animals on higher nutritive value pasture and those fed higher levels of supplementation had an increased ADG (0.40 vs. 3.21 lb).…”

Effect of growth path on the performance and carcass traits of Hereford steers finished either on pasture or in feedlot

“…Differences between the expected and observed LWGs at the end of first winter were probably due to favourable weather conditions during winter, with higher temperatures and lower rainfall than in an average year. Previous studies have reported similar differences in LW at the end of the growth phase for steers reared on different postweaning growth pathways (Ridenour et al 1982;Sainz et al 1995;Dicker et al 2001;Robinson et al 2001;Loken et al 2009).…”

“…However, most of the research has been focussed on finishing systems, without considering the effects of winter nutrition during rearing on subsequent finishing performance. The impact of improvement in nutritional status immediately after weaning on animal performance, tissuedeposition pattern and feed conversion ratio (FCR) during the finishing phase has been widely reported (Parks 1982;Owens et al 1995;Dicker et al 2001;Robinson et al 2001;Purchas et al 2002). Therefore, better nutrition throughout the inclusion of the feedlot at an early stage can influence the rate and pattern of animal tissue deposition, and modify the type of final product obtained.…”

Feedlot growth performance and carcass characteristics of steers backgrounded on buffel grass or buffel–Desmanthus mixed pastures

“…However, these studies did not investigate the feedlotfinishing growth performance and carcass quality of the animals. Backgrounding diet and weight gain influence subsequent finishing feed intake and growth performance, but results have been inconsistent (9)(10)(11). Reuter and Beck (12) reported that finishing average daily weight gain (ADG) and dry matter intake (DMI) decreased as backgrounding ADG increased in cattle.…”

“…However, the difference may not persist when animals are finished in the feedlot before slaughter ( 23 , 24 ). While some studies have evaluated the impact of the finishing diets on carcass quality traits ( 25 , 26 ), fewer studies have examined the effect of backgrounding on finishing growth performance and carcass quality ( 10 , 15 , 27 ). In addition, there is an existing knowledge gap on the feedlot growth performance of tropical beef cattle backgrounded on grass pastures augmented with desmanthus.…”