Prediction of intramuscular fat content and shear force in Texel lamb loins using combinations of different X-ray computed tomography (CT) scanning techniques

Computed tomography (CT) parameters, including spiral computed tomography scanning (SCTS) parameters, intramuscular fat (IMF) and mechanically measured shear force were derived from two previously published studies. Purebred Texel (n = 377) of both sexes, females (n = 206) and intact males (n = 171) were used to investigate the prediction of IMF and shear force in the loin. Two and three dimensional CT density information was available. Accuracies in the prediction of shear force and IMF ranged from R2 0.02 to R2 0.13 and R2 0.51 to R2 0.71 respectively, using combinations of SCTS and CT scan information. The prediction of mechanical shear force could not be achieved at an acceptable level of accuracy employing SCTS information. However, the prediction of IMF in the loin employing information from SCTS and additional information from standard CT scans was successful, providing evidence that the prediction of IMF and related meat eating quality (MEQ) traits for Texel lambs in vivo can be achieved

Relationships between mobilisation of body reserves in hill ewes and lamb production to weaning

Previous studies using X-ray computed tomography (CT) of Scottish Blackface hill ewes have shown that carcass fat, internal fat and muscle are depleted during pregnancy and early lactation and deposited during late lactation and the dry period (Lambe et al., 2003a). Muscle weights and proportions throughout the year are positively genetically correlated with total litter weight reared, largely due to increased litter size. Average weights of lambs reared were positively correlated with carcass fat weight or proportion pre-lambing and internal fat weight pre-mating, but negatively correlated with internal fat proportion pre-lambing (Lambe et al., 2005). However, is genetic potential to mobilise and regain increased amounts of tissue during the year positively associated with the ability to produce more and heavier lambs? The aim of this study was to address this question by relating total loss and gain of fat and muscle in ewes during the annual cycle with lamb production traits.</jats:p