Milking of Brown Swiss and Austrian Simmental cows in a herringbone parlour or an automatic milking unit

Abstract

Automatic milking systems (AMS) are becoming increasingly common on dairy farms and should be evaluated for their effect on cow welfare. Dairy cows’ stress responses during normal successful milking in a 2×6 herringbone milking parlour (HMP) were compared with their responses during normal successful voluntary milking in an automatic unit (AMU). We observed 42 cows: 12 Simmental and 11 Brown Swiss in the AMU, and 10 Simmental and 9 Brown Swiss in the HMP. Both prior to and during the observations each cow was milked in one system only. Behaviour during milking and durations of different phases of the milking procedure were observed directly two to six times per cow. Heart rate was recorded telemetrically. Samples of composite milk were analysed for cortisol using an enzyme-immunoassay. Milking lasted longer in the HMP than in the AMU (general mixed model: F 1,39=12.06, P=0.0013), after significant effects of milk yield, day of lactation and time of day had been taken into account. Location of the teats by the robot took longer in Simmental than in Brown Swiss cows (Mann–Whitney- U-test: U 11,12=32, P=0.037). Kicking and stepping with the hind legs was less frequent in the AMU than in the HMP ( U 23,19=76.5 for kicks; U 23,19=85 for steps; P<0.001 in both cases). Brown Swiss cows stepped less than Simmental cows in the AMU ( U 11,12=32, P=0.036). In the HMP, kicks occurred more frequently during the time period from the beginning of udder cleaning until cluster attachment was completed, than at other times (Friedman test: F 19,4=32.41, P<0.001; Bonferroni-corrected post-hoc-comparisons: P<0.01). There was no difference between groups in heart rate during milking. The AMS group had higher milk cortisol values than the HMP group ( U 23,19=130.5, P=0.026). This was probably not related to milking itself, but to other aspects of the system, and absolute values were not very high. In conclusion, Simmental cows may be more vulnerable during milking than Brown Swiss. Limiting the study to successful voluntary milking events without AMU attachment failure, there were no indications of more stress in the AMU than in the HMP.