Using milk fatty acids as biomarkers to improve feed conversion ratio in dairy sheep

Feed costs constitute a substantial portion of livestock production costs; therefore, improving feed efficiency (FE) is a major research topic nowadays. However, obtaining individual FE records in commercial populations requires specialized infrastructure. This research aimed to study the association between milk fatty acids (MFA) and FE in Assaf dairy sheep to determine potential MFA biomarkers for FE. Individual feed conversion ratio (FCR) of 39 ewes were estimated. Spearman correlation, regression, and orthogonal partial least squares were then used to analyze the relationship between FE and a profile of 101 MFA. We identified 33 MFA significantly associated with the FCR. These MFAs achieved a predictive performance of 0.82 for the FCR, and were successfully used to identify the most and least feed efficient animals. Thus, we propose a list of potential biomarkers to validate as an easyto- measure phenotype for FE trait in a larger population.