Carcass traits and meat lipid profile of cull cows fed palm kernel cake.

Context. Among the by-products derived from oilseeds, palm kernel cake (PKC) contains high concentrations of protein, fat, and fibre, which allows some flexibility in the use of this ingredient in ruminant diets. Aim. This study examined the effects of including palm kernel cake (PKC) in high-grain diets for cull cows on production performance, carcass traits, and meat fatty acid profile. Methods. Thirty-six ½ Girolando cows at 83 ± 5 months of age, with an average liveweight of 384.88 kg ± 59.18, were confined in collective stalls for 90 days. The animals were distributed into the following four diet groups: 0% (control), 8%, 16%, or 24% inclusion of PKC in the diet dry matter (DM). Key results. On the basis of regression analysis, the highest slaughter weight and carcass weight were at PKC inclusion levels of 11.5% and 10.3% respectively. Backfat thickness was greatest (8.8 mm, P < 0.01) in the carcasses of cows fed the diet with 15.1% PKC (on the basis of regression analysis), whereas the total lipid content in the meat decreased linearly (P < 0.05) with PKC inclusion. The C10:0, C12:0, C14:0, C14:1, C16:0, C16:1, C17:1, C18:0, C18:2n6t, and C20:5n3 fatty acids in the longissimus thoracis muscle responded quadratically (P < 0.05) to the inclusion of PKC. The highest concentration of desirable fatty acids was obtained with the inclusion of 11% PKC in the diet (on the basis of regression analysis). There was a linear increase in C14:1, C20:2, and C22:2 fatty acids and Δ9 desaturase 14 and 16 activity indices in the muscle of cows fed PKC. Conclusion. We recommend the inclusion of 10% PKC in the diet of cull cows fed high-grain diets. Intramuscular fatty-acid proportions were appreciably different from those reported for young B. taurus steers and heifers finished on high-concentrate diets. Implications. Therefore, inclusion of PKC is an excellent alternative to reduce production costs, having the availability and quality of the product as a limiting factor, since PKC is an industrial by-product. [ABSTRACT FROM AUTHOR]