Growth performance and carcass characteristics of Australian prime lambs supplemented with pellets containing canola oil or flaxseed oil

The objective of this study was to investigate the effects of enriched omega-3 oil supplemental pellets, breed and gender on lamb liveweight (LWT), body conformation and carcass characteristics, and to assess the relationships between body conformation and growth under an intensive finishing condition. Sixty ewe and wether prime lambs 7 months old were randomly allocated to one of five dietary treatments: no oil inclusion (Control); 2.5% canola oil; 5% canola oil; 2.5% flaxseed oil and 5% flaxseed oil, balanced by breed (purebred Merinos (M x M) and Corriedale x Merino (C x M) and White Suffolk x Corriedale (W x C) first crosses). Lambs were individually supplemented with 1 kg pellets per day and had free access to lucerne hay and water throughout the 7-week feeding trial, after a 3-week adaptation. Dietary oil inclusion did not cause significant differences in daily feed intake, growth performance and carcass characteristics (P > 0.05). However, first-cross W x C lambs had significantly higher feed intake, chest girth and body conformation score (P < 0.05) than M x M and C x M lambs. Carcass weight, dressing percentage and fat depth of crossbred lambs were significantly higher than those of M x M (P < 0.05). Significant interactions between oil inclusion and breed on average daily gain (ADO) and feed conversion ratio were observed. There were positive and highly significant correlations among LWT, ADG and body conformation measurements (P < 0.01). These findings suggest that prime lamb producers can better manage and match their breeding goals with feed resources by supplementing first-cross C x M lambs with pellets containing 5% canola oil or feeding first-cross W x C lambs with 5% flaxseed oil pellets during the 10-week intensive finishing period.