J.H.M. Metz

The influence of social hierarchy on the time budget of cows and their visits to an automatic milking system

Abstract The influence of social dominance on visits to an automatic milking system (AMS) was studied in 30 crossbred Holstein-Friesian dairy cows, kept in a cubicle house. The cows were fed concentrate and milked in the AMS, which consisted of two selection units (where cows were automatically identified and either sent to milking or back to the herd) and one milking unit. In the first phase of the experiment (A), cows had a milking regime of 3 times day −1 . At first they always received 100 g of concentrate when they visited a selection unit (A1). Later, they were dispensed concentrate in the selection unit only if they still had some of their daily ration owed to them (A2). In the second experimental phase (B), ten cows had a milking regime of 5 times day −1 and 19 cows of 3 times day −1 (one cow was culled due to severe mastitis). Concentrate was dispensed in time windows corresponding with the planned milking frequencies, and taking the individual pattern of visits to the AMS into account, in such a way that cows which visited the AMS less than they should according to their planned milking frequency were stimulated to pay more visits by being rewarded with a fixed amount of concentrate (100 g) in the selection unit even if they had already consumed their concentrate allocation for that particular feeding period. Social dominance was expressed as the dominance value of each cow, representing the relative number of cows which are subordinate to the cow concerned. In A and B, there was a negative correlation between the cows dominance value and her daily concentrate allotment ( r = −0.56, P r = −0.45, P r = 0.55 and 0.53, respectively, P r = 0.45, P P P P P It is concluded that the introduction of fully automatic milking systems will trigger effects of social dominance, especially concerning the timing of visits to the AMS and the feeding gate and the waiting of low ranking cows in front of the AMS.

Behaviour of dairy cows under free or forced cow traffic in a simulated automatic milking system environment

Abstract The introduction of fully automatic milking systems (AMS) on dairy farms can only succeed if cows visit the system more or less voluntarily, at regular intervals. This can be arranged by either forced or free cow traffic. In the case of forced cow traffic, the AMS is the only route from the lying area to the feeding area. An alternative is free cow traffic, where the cows can decide whether to visit the AMS or not. The behaviour in 3 × 20 crossbred Holstein Friesian dairy cows in three experiments (experiment Ia, Ib and II) was studied in a cubicle house with a selection system consisting of a selection stall and a concentrate feeder, simulating an AMS. Cows could obtain 250 g of concentrate in the system once every six hours. Actual milking occurred in a conventional milking parlour twice a day. Experiment Ia consisted of (1) a reference phase with no use of the selection system, (2) free cow traffic, (3) forced cow traffic, and (4) a reference phase. Experiment Ib was a repetition of experiment Ia. Experiment II was divided into (1) a reference phase with no use of the selection system, (2) forced cow traffic with two one-way passages between the feeding and lying areas, (3) forced cow traffic with one one-way passage, (4) free cow traffic with one free passage between the feeding and lying areas, and (5) free cow traffic with two such passages and (6) a reference phase. The number of visits paid to the selection system by individual cows appeared to be consistent in the different phases in each experiment (r = 0.52 in experiment I (P

Effect of sward height and distance between pasture and barn on cows’ visits to an automatic milking system and other behaviour

Two experiments were conducted to study the effects of sward height (experiment I) and the distance between barn and pasture plot (experiment II) on cows’ visits to an automatic milking system (AMS) and other behaviour. The study was carried out in a situation in which grazing was combined with fully automatic milking. The cows had to visit the system voluntarily without interference of the farmer. The AMS was continuously available in the barn adjacent to the pasture. The pasture was divided into ten plots of 1 ha for the two experiments and the preceding habituation. The same group of 24 Holstein Friesian cows was used in both experiments. The cows were allowed to spend up to 15 h at pasture daily. The results of experiment I (rotational grazing) showed that the total number of AMS visits increased from 4.4 to 7.3 and that the number of milkings increased from 2.6 to 3.0 when sward height decreased (P<0.01). The results of experiment II (strip grazing) showed that a distance of 360 m between pasture and barn did not affect the cows’ visits to the AMS. In both experiments, cows preferred to lie in the pasture, when available, rather than in the cubicles, and tended to visit the barn group-wise and to enter the AMS in close succession. As a consequence, in the period that the cows had access to the pasture there were peaks in AMS visits, and the AMS was unvisited for several hours.