Effects of fresh forage inclusion in diet of high performance dairy cows on milk production and composition

The aim of this research was to evaluate the effects of partial substitution of total mixed ration (TMR) with fresh forage in the diet of high performance dairy cows, on milk production and composition. Two trials were performed, comparing a cow diet based on TMR with high percentage of maize silage and concentrates (TMR) with one where cows were fed TMR plus freshly harvested forage (TMR+F). In trial 1 the fresh forage was utilized during an advanced stage of maturity, whereas in trial 2 the fresh forage was utilized during an early stage of maturity. In both trials the inclusion of fresh forage in the cow diet did not affect the milk production and its contents of protein and fat. The fresh forage affected the milk fatty acid (FA) composition, increasing the vaccenic and linolenic acids and conjugated linoleic acid (CLA) contents. A supplement of fresh forage to TMR can modify the nutritional properties of cow milk without changing the milk production