The use of lasalocid in long-term feeding of Friesian steers

Abstract

Seventy-two Friesian calves with a mean (¦ s.e.) liveweight of 130.6 ¦ 3.82 kg were divided into 8 groups which were then allocated to 2 dietary treatments, a grain-based feedlot diet (Cont) and the same diet with lasalocid added at the rate of 22 g/t (Las). After 127 days (period 1) of feeding, 2 of the groups in the Cont treatment were changed to the Las treatment (Cont -> Las) and 2 on the Las treatment were changed to the Cont treatment (Las -> Cont). The animals were slaughtered after a further 168 days of feeding (period 2). Liveweight gain of the Las group (1.39 kg/steer.day) was superior to that of the Cont group (1.28 kg/steer.day) in period 1. In period 2, liveweight gain in the Las and Las -> Cont groups was superior to that of the Cont -> Las group. Food conversion ratio in the Las group was lower than in the Cont group during period 1 but there were no differences between treatments in period 2. The slaughter data showed that the Friesian steers produced acceptable carcasses in terms of carcass weight and fat depth. The study showed that Friesian steers can be successfully grown to slaughter weight on high grain diets and that long-term lasalocid supplementation results in improved liveweight gain and feed conversion efficiency.