Residual effect of winter undernutrition applied over the first four lactations in dairy cows

Abstract

During the first 12 weeks of their fifth lactation, 29 cows received ad libitum a diet composed of 55% maize silage and 45% concentrate. During their first four lactations, these cows received a winter ration composed of hay and grass silage, supplemented at three levels (H, M and L) of concentrate allocation. Over the summer period, all animals had been turned out to pasture together. Between the fourth and fifth lactation, milk production of the first 12 weeks of lactation increased by, respectively, 3.7,1.9 and 5.4 kg/day in groups H, M and L. Whatever the group, these increases were highly variable among cows. This variability was explained by the variations of nutritive supply between the fourth and the fifth lactation, due to the differences in feed intake. This trial demonstrates that cows submitted to severe undernutrition over their first four lactations maintain a large response ability when fed liberally.