Effect of the percentage of concentrate on intake pattern in mid-lactation goats
Publication Type: |
Journal Article |
Year of Publication: |
2012 |
Authors: |
Amélie Serment, Sylvie Giger-Reverdin |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
dairy goat, individual differences, intake pattern, rumen ph |
ISBN: |
0168-1591 |
Abstract:
The aims of this work were to study the between-individual and between-week variations of intake patterns, to examine the relationship between intake pattern, rumen pH and milk production, to study the effects of the percentage of concentrate on intake patterns and to compare methods describing intake patterns. Thirteen goats (95 ± 4 days in milk) were fed ad libitum a diet with 52.5% of concentrate (on dry matter basis) at first week. They were assigned to a low-concentrate diet (35%) or a high-concentrate diet (70%) from week 4 to week 10 of the trial. Intake patterns were studied according to three methods: using an index of the intake rate during first hours after feeding (proportion of DM eaten at 90 min after the afternoon feeding), modelling cumulative intake profiles with an exponential model, and using a segmentation-clustering method. Even though animals received the same diet at the onset of the trial, a large between-goat variability of the ingestive behaviour was observed. Animals were classified according to 3 profiles of ingestive behaviour: fast, intermediate and slow eaters during the first 90 min after afternoon feeding. Several animals kept the same profile during 10 weeks and in spite of a modification of their diet (from 52.5 to 35% of concentrate), whereas the others changed their profile (fast or intermediate eater to slow eater) when they were fed the high-concentrate diet. The intake rate was related to the rumen pH drop, and raw milk yield (P = 0.02) and tended to be related to total dry matter intake (P = 0.09). In week 4, the percentage of concentrate had no effect on the total dry matter intake and the intake rate. Only the duration of the first eating bout was reduced by increasing the dietary percentage of concentrate (P = 0.009). At the end of the trial, the intake rate (P = 0.001), the duration (P < 0.001) and the dry matter (P < 0.001) eaten during the first eating bout were reduced for animals fed the high-concentrate diet. This adaptation of the ingestive behaviour allowed the animals to limit the decrease in rumen pH. None of the methods used to describe intake patterns were perfect, but they all add information to help in interpreting the data.