Relationship between intramuscular fat content in longissimus thoracis and hair fatty acids in finishing crossbred bulls

Intramuscular fat (IMF) content below 6% in live cattle is difficult to estimate accurately. Therefore, this study tested whether fatty acids in the IMF of LT and hair correlate to each other, and whether fatty acids can be used to predict IMF. Forty-four finishing crossbred bulls from two farms were examined. Each bull had a hair sample collected before slaughter, and two days post-slaughter, LT muscle samples were collected to assess IMF (range: 2.3–6.6%) and fatty acids. Predictions of IMF from hair fatty acids were developed using linear, non-linear and non-parametric approaches. Nineteen congruent fatty acids could be detected in hair and LT. Although proportions varied, lauric and oleic acids showed positive correlations between LT and hair ( r = 0.48–0.49; P ≤ 0.001). Lauric acid in hair showed also a consistently prediction of IMF and moderate rank-based association between predicted and observed IMF across all tested prediction models. For the first time, the study presents evidence that hair fatty acids taken shortly before slaughter provide significant information about the IMF in bulls. To use this information for breeding or feeding strategies, it would be necessary to extend hair sampling by testing earlier stages in life.