By Coulon, J. B. and Garel, J. P. and P, D. Hour and Petit, M., Annales de Zootechnie, 1996
Description
In their first 4 lactations 148 dairy cows were given diets containing grass silage ad libitum, hay 4 kg/day and high, medium or low concentrate levels during the winter period (H, M and L) and, for levels M and L, allocation patterns, standard (S) or flat rate (F). First-lactation cows were allocated to a treatment in which they remained until lactation 4 or when culled. Winter concentrate allocation was individually predetermined for the first 4 lactations according to expected milk yield. During summer, all cows grazed together as a single group. The occurrence of mastitis, reproductive performance (days open and interval between calving and first oestrus) and longevity were not significantly different between treatments. Foot lesions were more frequent in group H than in other groups. Effect of treatment on production performance was studied in cows having lactated for at least 12 weeks in the winter period in at least 3 successive lactations. Between lactations 1 and 3, liveweight at calving increased by 72, 44 and 36 kg in groups H, M and L, respectively, and milk yield over the first 12 weeks of lactation by 8.3, 5.9 and 6.1 kg/day, respectively (P<0.01). These differences were more pronounced in the highest-producing cows. When considered over the first 40 weeks of lactation, differences in production increase between lactations 1 and 3 were not significant (1175, 997 and 1159 kg in groups H, M and L, respectively), due to greater compensation over the summer period for groups M and L during lactation 3. There was no significant difference in production and reproductive performances between groups S and F
In their first 4 lactations 148 dairy cows were given diets containing grass silage ad libitum, hay 4 kg/day and high, medium or low concentrate levels during the winter period (H, M and L) and, for levels M and L, allocation patterns, standard (S) or flat rate (F). First-lactation cows were allocated to a treatment in which they remained until lactation 4 or when culled. Winter concentrate allocation was individually predetermined for the first 4 lactations according to expected milk yield. During summer, all cows grazed together as a single group. The occurrence of mastitis, reproductive performance (days open and interval between calving and first oestrus) and longevity were not significantly different between treatments. Foot lesions were more frequent in group H than in other groups. Effect of treatment on production performance was studied in cows having lactated for at least 12 weeks in the winter period in at least 3 successive lactations. Between lactations 1 and 3, liveweight at calving increased by 72, 44 and 36 kg in groups H, M and L, respectively, and milk yield over the first 12 weeks of lactation by 8.3, 5.9 and 6.1 kg/day, respectively (P<0.01). These differences were more pronounced in the highest-producing cows. When considered over the first 40 weeks of lactation, differences in production increase between lactations 1 and 3 were not significant (1175, 997 and 1159 kg in groups H, M and L, respectively), due to greater compensation over the summer period for groups M and L during lactation 3. There was no significant difference in production and reproductive performances between groups S and F
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