Association of 20 candidate gene markers with milk production and composition traits in sires of Reggiana breed, a local dairy cattle population

Reggiana is a local dairy cattle breed that currently counts about 2000 cows reared mainly in the province of Reggio Emilia (North of Italy). Reggiana cows are less productive than Holstein cows opening questions about the profitability of this breed whose milk is used to produce a niche brand of Parmigiano-Reggiano cheese. For these reasons, protein content and yield of the Reggiana milk are very important traits. With the aim to identify markers that could be useful to describe genetic variability in this breed and eventually to use them in conservation and marker assisted selection programs, we genotyped 22 DNA polymorphisms of 17 candidate genes (ABCG2, CRH, CSN3, CYP11B1, DGAT1, FGF2, GH1, GHR, KIT, LEP, LGB, ORL1, POU1F1, PRLR, SPP1, STAT1 and TG) in 128 Reggiana sires for which semen was available and we analyzed association among 20 polymorphic markers and milk yield, protein yield (PY), fat yield (FY), protein percentage (PP) and fat percentage (FP) estimated breeding values. Five markers, four of which on Bos taurus chromosome (BTA) 14 (DGAT1 p.K232A, CYP11B1 p.A30V, TG g.9509279C > T, CRH p.S45D) and one on BTA19 (GH1 p.L153V), were highly associated (P < 0.01) with several production traits (PP, FY and PY; FP; PY; FY; PP and FP; respectively). This study is the largest investigation of molecular markers carried out in this breed so far and represents one of the few attempts to identify DNA markers affecting production traits in a cattle breed constituted by a very small population. Obtained results could open new possibilities for conservation and breeding programs in Reggiana cattle.