The impact of clean fleece weight and bodyweight selection in Merinos on meat traits in the progeny

Abstract

The carcasses of 136 Merino wether lambs from a single bloodline were studied to determine the impact of phenotypic selection for clean fleece weight (CFW) and bodyweight (BWT) on meat quality characteristics. The lambs were the progeny of sires and dams that were selected for high or low CFW and high or low BWT using hogget phenotypic data, where the dams were managed at 10 or 15 dry sheep equivalent/ha during gestation and from marking to weaning. Maternal stocking rate was found to have no significant effect on any meat traits, except to reduce fatness in high BWT lambs. High CFW selection led to increased glycolytic activity in muscle reflected by lactate dehydrogenase (LDH) activity. Phenotypic BWT selection increased hot carcass weight and decreased fatness, lowered temperature at pH 6.0, and showed considerable variation in LDH activity and the ratio of LDH to isocitrate dehydrogenase. It is clear from this study that the stocking rate of the dam during gestation and lactation, and her selection on the basis of CFW or BWT phenotype had no large negative impact on the meat traits of her male progeny.