This is the author's final version of the contribution published as:Cosenza, Gianfranco; Macciotta, Nicolò P P; Nudda, Anna; Coletta, Angelo; Ramunno, Luigi; Pauciullo, Alfredo. A novel polymorphism in the oxytocin receptor encoding gene (OXTR) affects milk fatty acid composition in Italian Mediterranean river buffalo. THE JOURNAL OF DAIRY RESEARCH. 84 were tested using a mixed linear model. The OXTR CC genotype was found significantly associated with higher contents of Odd branched-chain fatty acids (OBCFA) (P0.0006), polyunsaturated FA (PUFA n 3 and n 6) (P0.0032 and P0.0006, respectively), Stearic acid (C18) (P0.02) and lower level of Palmitic acid (C16) (P0.02). The results of this study suggest that the OXTR CC genotype animals might be useful in selection toward the improvement of milk fatty acid composition.