The effects of restricted feed access and social rank on feeding behavior, ruminating and intake for cows managed in automated milking systems

In the present research the effects on feed intake and chewing activities of dairy cows subjected to three different degrees of controlled cow traffic were examined. The hypothesis tested was that restricted access to the feeding areas provokes effects on chewing activities related to feeding and rumination. The cows were subjected to three different cow traffic routines in a carry-over design with three periods of 3 weeks each. In each period, the cows were subjected to one of the following cow traffic routines: (1) the free cow traffic routine (FR) that implied cows always had access to the feeding areas through the control gates; (2) the selective cow traffic routine (SE) that implied cows had access to the feeding areas through control gates until 5 h after the last milking; (3) the forced cow traffic routine (FO) that implied cows never had access to the feeding areas through the control gates. Despite no difference in feed intake between cows of high and low social rank, the cows of high social rank spent significantly more time chewing while feeding: 214 min/day for cows of high social rank and 175 min/day for cows of low social rank, respectively. The FO enhanced the social effects on chewing activities; cows of high social rank tended to have more chews per kilogram of dry matter intake (512 chews/kg DM) compared to cows of low social rank (382 chews/kg DM). During FR cows had a higher dry matter intake and ruminated for a longer time compared to the other cow traffic routines. It was concluded that forced cow traffic provoked effects that may have negative effects on feed intake and cow welfare. (C) 2006 Published by Elsevier B.V.