| dc.description.abstract | In dairies with multiple (two) AMS systems per group of cows, the individual AMS stalls can be positioned tail-to-tail (TT) or head-to-tail (HT). Tail to tail orientation requires the cow to enter the stall asymmetrically if it selects one stall after the other. For head to tail orientation, the cow enters any of the stall, always symmetrically. These different AMS orientations may lead to a cow’s preference for one of both stalls. This is called preference behavior which goes from cross use of both stalls to selective use of one of both stalls.
In this study we investigated if difference in orientation lead to preferential behavior, variation in milking intervals and production. 16 farms that met our criteria were selected, consisting of 9 farms with 2 tail to tail orientated AMS stalls and 7 farms with 2 TT orientated AMS stalls. Visiting data between November 2011 and December 2012 was collected on farm and analyzed afterwards.
There are large differences in AMS use preference behavior distribution between farms and there is over twice as much extreme selective use (90-100%) of 1 AMS on the tail to tail AMS farms as there is on the head to tail AMS farms (19.5% and 8.6%). No significant differences in performance parameters have been found between the orientations.
Some significant differences have been found in cows with different degrees of AMS preference behavior. There are 4 degrees of selective use (from mild to extreme preference) compared to the reference group (cross use, no preference) for 8 stages of lactation, in total 32 groups that are compared to 8 reference groups. For the daily number of visits, 14 of 32 groups were significantly different (P = 0.05) up to 0.2 visits per day in the first 20 days of lactation. Cows with more preference tended to be significant different from cows with no preference behavior. For interval variation only 2 of 32 groups were significantly different with slightly prolonged interval variation. Only 1 of 32 groups had a significant different milk yield, -0.67 kg milk for 5th and higher lactation cows in 299-399 days of lactation. For milk yield per visit, 5 of 32 groups had significantly more milk yield per visit compared to the reference category.
It can be concluded that the different AMS orientations lead to difference in visiting behavior but does not lead to differences in milking performance. | |
