Liveweight gain, herbage intake, and ingestive behaviour in Compudose®‐treated and untreated steers at pasture

Abstract

Twenty 14-month-old Friesian steers and sixteen 14-month-old Angus cross steers were randomly assigned within "breed" to Compudose® treatment (24 mg of oestradiol-17β impregnated in a silicone rubber implant with an active life of 200 days) or left untreated. Fasted liveweight gain (LWG) of the steers was recorded as were calculated herbage intakes and grazing behaviour, measured on two occasions (days 34-50 and days 168-184 of treatment). Compudose-treated steers gained a mean of 856 g/day compared with 710 g/day by the control steers over the treatment period (20.6% increase, P < 0.001). The final fasted liveweight of treated steers was improved by 29.5 kg (7.1%) over that of the untreated steers (P < 0.001). There were no significant differences in the amount of herbage eaten or in components of grazing behaviour between the treated and untreated groups. Under pastoral conditions, as in feedlots, Compudose treatment appears to increase both LWG and the efficiency of that gain.

Effects of Compudose® and Rumensin®, alone or in combination, on the growth, and carcass and meat quality of steers finished on pasture

“…This is similar to the result of Aranda-Orsorio et al (1996) who treated steers with Compudose under pastoral grazing conditions and found that LWG increased by 21.8%. Bass et al (1989) and Baker et al (1992) reported LWG increases of between 5 and 30% in Compudose-treated cattle fed pasture.…”

“…Compudose® is an implanted hormonal growth promotant containing the naturally occurring steroid oestradiol-176. Although little work has been conducted under grazing conditions, increases in liveweight gain and feed utilisation efficiency of cattle have been recorded at pasture with each of these products (Potter et al 1986;Aranda-Orsorio et al 1996). The effects of Rumensin appear to be additive to the effects of some implanted hormonal growth promotants (Cochran et al 1990) but additivity with Compudose does not appear to have been examined under New Zealand grazing conditions.…”

Effect of sward surface height on herbage intake and performance of finishing beef cattle

“…Previous studies by Morris et al (1993) at Massey University using intraruminal chromium controlled release capsules found that DMIs were approximately 2.60 and 2.87 kg 100 kg LW" 1 for Charolais x Angus steers (325 kg LW) grazing at 5 and 10 cm SSH during spring, and growing at 0.67 and 1.47 kg day^1, respectively. Aranda-Osorio et al (1996) showed that 14-month-old Angus x (Hereford x Friesian) and Friesian steers (300 kg LW) growing at 0.71 kg day" 1 consumed 2.31 kg 100 kg LW" 1 during spring. Comparative values for the current trial were approximately 1.03 and 1.61 kg 100 kg LW" 1 for steers grazing at 5 and 10 cm during summer, and growing at 0.32 and 1.10 kg day" 1 .…”