Comparison of Revalor XS, a new single-dose implant, to a Revalor IS and Revalor S implant strategy in finishing steers 1

A commercial feedlot study compared effects of a Revalor IS/Revalor S implant program to a Revalor XS single-implant program on performance and carcass characteristics of feedlot cattle. Yearling crossbred steers (1,356; BW = 313.3 ± 16.0 kg) were used in a randomized complete block designed trial. Pens were assigned randomly to 1 of 2 implant treatments. Cattle on the Revalor IS/Revalor S treatment were reimplanted on d 80 with Revalor S. Diets consisted of 54.9% dry-rolled corn, 35% wet distillers grains plus solubles, 5.5% mixed hay, and 4.6% liquid supplement (DM basis). There were no differences (P = 0.96) in DMI because of treatment. Also, no differences (P > 0.90) in final BW, ADG, or G:F were observed on a carcass-adjusted basis. No differences in final BW, ADG, and G:F (P > 0.50) were observed for live performance. Marbling score, 12th-rib fat thickness, LM area, and YG were unaffected (P > 0.69) by implant strategies. Steers on the Revalor XS treatment had a greater number of Low Choice carcasses (P = 0.01) and a lower number of Select carcasses (P = 0.02) compared with Revalor IS/Revalor S, with 58% of Revalor XS cattle grading Low Choice and 50% of Revalor IS/Revalor S cattle grading Low Choice. Steers on the Revalor XS treatment tended to have a greater (P = 0.11) number of USDA YG 5 carcasses. Steers implanted with Revalor XS performed similar to cattle implanted initially with Revalor IS followed by Revalor S.