Seasonal variation of milk fatty acid profiles from dairy cows crossbred with US Brown Swiss in low-input farms in Switzerland

摘要

The three main Brown Swiss populations in Switzerland are US Brown Swiss (BS), Braunvieh and Original Braunvieh (OB). Stergiadis et al. (2015) showed that summer milk fatty acid (FA) profile varied between crossbred cows, with genetics from these populations with the relative effect influenced by pasture intake. Cows' diets, in particular pasture intake, has been suggested to be the main reason for seasonal variation in milk fat composition (Butler, 2011). This study investigated the interaction of season and the contribution of B S in cows' genetics on milk FA profile, focusing both on nutritionally undesirable saturated FA (SFA) and desirable monounsaturated FA (MUFA), such as vaccenic acid (VA, t11 C18:1), and polyunsaturated FA (PUFA), such as omega-3 FA (n-3), omega-6 FA (n-6), rumenic acid (RA, c9t11 C18:1 conjugated), a-linolenic (ALN, c9c12c15 C18:3) and eicosapentaenoic acid (EPA, c5c8c11c14c17 C20:5).