Carcass traits of Rambouillet and Merino × Rambouillet lambs and fatty acid profiles of muscle and subcutaneous adipose tissues as affected by new sheep production system

Rambouillet and Merino×Rambouillet lambs were assigned to production systems varying in physical environment and diet: RF (raised-floor, open-sided barn/85% oat hay–10% wheat–5% molasses), FL (feedlot/high-concentrate), and P (pasture/grazing plus supplement). Although treatment duration was varied to produce similar final weights, RF lambs were heavier than P lambs, but dressing percentages were similar. Backfat thickness was less with P and for Merino cross lambs. RF feed was higher in saturated fatty acids (SFA) percentage than FL feed and P supplement, but lower compared to pasture plants. For both breed types, muscle tissue from RF was higher in SFA and lower in polyunsaturated fatty acids (PUFA) percentage than that from FL or P. In adipose tissue, SFA and PUFA tended to be higher and monounsaturated fatty acids were lower with RF for Merino cross lambs. Nevertheless, 16:0 or 18:1 percentage differences among P, FL and RF lamb tissue samples were minor vs. large variations among their respective diets.