Effect of Linseed Feeding on Carcass and Meat Quality and Intramuscular Fatty Acid Profile of Simmental Bulls Slaughtered at Different Ages

The inclusion of linseed in cattle diets can improve the fatty acid (FA) profile of meat, but the effects of supplementation at different ages have been insufficiently studied. Hence, this study examined the effects of linseed supplementation and slaughter age on beef cattle carcass and meat quality, FA profile, and lipid oxidation. Eighty Simmental bulls (initial age 221 ± 9 days) were evenly allocated the experimental treatments, consisting of a control diet and a linseed-enriched diet (around 1% whole linseed) fed to the bulls until slaughter at 13 or 17 months of age, in a 2 × 2 factorial design. After slaughter, carcass traits, meat quality, FA profile, and oxidative stability (TBARS test) of the longissimus thoracis muscle were determined. Linseed feeding increased the dressing percentage (<i>p</i> < 0.01) at both slaughter ages but had limited effects on overall carcass and meat quality. The intramuscular fat of linseed-fed bulls contained less saturated FA (<i>p</i> < 0.01) and more beneficial n-3 PUFAs, such as eicosapentaenoic (<i>p</i> < 0.05) and α-linolenic acid (<i>p</i> < 0.001), especially in younger bulls. Although the atherogenic index and n-6/n-3 ratio improved, they remained above the recommended values. Lipid oxidation was higher in linseed-fed (<i>p</i> < 0.05) and younger bulls (<i>p</i> < 0.001). These results suggest that linseed supplementation can improve the beef's FA composition, but higher levels, especially in older animals, and antioxidant strategies may be required to optimise meat stability and nutritional value.