Feedlot Performance and Carcass Traits of Texas Rambouillet Feeder Lambs Implanted With Growth Implants

R. S. Sluiter, B. J. May, M. W. Salisbury, C. B. Scott, G. R. Engdahl, B. F. Craddock


Three hundred cross-bred lambs with an average initial weight of 33.5 kg were used to compare the effects of three different hormone implants versus a control on lamb performance (ADG) and carcass characteristics.  Lambs were divided into four groups and assigned implant treatments as follows: no implant (CON), Synovex1 (SYN), Ralgro2 (RAL), or Component C3 (COM).  On d 0, lambs were weighed, ear tagged and implanted according to treatment.  Lambs were fed by a self-feeder.  Weights were recorded on subsequent d 28, 56, 84, 97, and 108 and as end-weights were reached, lambs were slaughtered.  Backfat thickness, cross-sectional ribeye area, USDA yield and quality grade measurements were recorded.  Analysis showed significantly higher ADG (P < 0.05) in COM and SYN lambs compared to CON d 28 through d 108.  On d 56, RAL lambs also exhibited higher (P < 0.05)  ADG than CON lambs.  Carcass evaluations yielded no conclusive evidence of improved quality of implanted vs. CON carcasses.  A majority (95%) of carcasses received “choice” quality grades and yield grades of 3 to 5 thereby implying improved ADG with hormone implant use, with no simultaneous improvements in carcass quality.


sheep; feedlot; implants; carcass

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