LAUSR

The objective of this experiment was to determine the effects of dietary inclusion of lasalocid in combination with zeranol implants on the performance and carcass characteristics of hair sheep. Thirty wether hair lambs (BW = 25.8 + 4.6 kg) were stratified by BW and BCS and randomly assigned to 1 of 2 experimental treatments in a randomized complete block design. The treatments included no implant or ionophore (CON); and the experimental treatment, receiving the ionophore lasalocid (Bovatec® 91; Zoetis, Kalamazoo, MI) and anabolic zeranol implants (Ralgro®; MSD Animal Health, Spartan, RSA; LZ). Lambs on the LZ treatment received 12 mg of zeranol on d 0, 56, and 112, unless lambs were harvested prior to day 112, and consumed an average of 35 mg per day of lasalocid. Lambs had ad libitum access to feed and water throughout the experiment and were housed in individual, slatted floor pens. Performance data were collected on d 0, 14, 28, 56, 84, and at harvest. After d 84, harvest dates were selected and lambs were harvested by block based on proximity to ideal harvest weight and fat thickness. Lasalocid in the diet combined with zeranol implants increased final BW by 14.2% in comparison to CON (P < 0.01). Overall ADG was increased by 36.2% (P < 0.01), and overall G:F was improved by 24.4% for LZ when compared to CON (P = 0.01). There was no difference in overall DMI between treatments (P = 0.13). Hot carcass weight (HCW; P < 0.01), and loin eye area (LEA; P < 0.01) were also greater for the LZ treatment. Dietary inclusion of lasalocid in combination with zeranol implants improved overall BW, ADG, and feed efficiency as well as HCW and LEA in hair sheep.