Effect of energy supply on performances of dairy cows fed with hay-based ration

Abstract

A total of 48 dairy cows (Abondance breed) were used in a 2-year experiment. The experiment was designed to examine the effect of concentrate levels during the winter period in addition to hay from native mountain grassland (Northen Alpes) offered ad libitum. Treatment H received concentrate at a high level and treatment L at a low level (2 kg/j less than treatment H). The composition of the concentate was adjusted to allow the same nitrogen supply for the 2 treatments. During winter (weeks 1-16 of lactation) milk production of treatments H and L were similar (17.2 kg/j vs. 16.7 kg/j). Protein content was higher (+ 1 g/kg, P < 0.01) in treatment H. Body reserves losses were higher in treatment B. The fill value of hay was low (between 1 and 1.05 UEL/kg MS).