Variación estacional en la composición química y en el perfil de ácidos grasos de la leche de vaca

Abstract

Instead of the fact that producers try to keep homogeneous milk quality for satisfying dairyindustry requirements, chemical composition and fatty acids (FA) profile of cow's milk undergoesseasonal variations due to changes in feed ingredients. The objective of this study was to evaluateseasonal variations in milk quality in response to changes on cows’ nutrition, motivated by variationson weather conditions (average temperature and accumulated precipitation), when cows are movedfrom a ration with fresh forage at grazing to another with silage and concentrate in stable. Protein, fatand saturated FA content were measured in milk during two years in The Netherlands showing lowvalues at grazing (p<0.001) in spring-summer and high values when animals feed silage andconcentrate ration (p<0.001) in autumn-winter. The opposite occurred with unsaturated FA andconjugated linoleic acid (CLA) which were higher (p<0.001) in spring-summer with fresh forage thanin autumn-winter with silage and concentrate. It is important to analyze the effect of seasonal