The Animal Welfare Science Centre The effect of milking shed noise on dairy cow behaviour using a Y maze Adele Arnold (NZL) University of Melbourne Animal Welfare Science Centre Primary Industries Research Victoria, Australia

Introduction  The milking parlour is a novel and possibly stressful environment for dairy cattle. –Human contact –Conspecifics –Physical environment:  illumination, noise, confinement, flooring surfaces, etc.

Noise in the milking parlour  The background sound level in a normal commercial milking facility ranges from dB  Acknowledgment of both physiological and psychological effects of environmental noise on human health.  What effect does this noise have on the behaviour and physiology of the dairy cow?

Y maze choice test  Aimed to evaluate the effect of milking parlour noise on choice behaviour of heifers using a Y maze  Also measured heart rate (HR), time to choose and ease of moving animals

Y maze apparatus  The Y maze contains two alternative directions of travel (short maze arms)  Subjects were trained to form associations between each direction and either presence or absence of noise

Procedure Day 0: habituation3 trials Day 1: training + test5 trials Day 2: training + test5 trials Day 3: one-off test1 trial  For each animal, the noise stimulus was presented in the first arm entered on day 1.  16 heifers

Maze side choice ab, p<0.01 a bb b

Additional measurements 1. Training trials: ­ Heart rate in maze arm ­ Restlessness in maze arm ­ Number of stops ­ Handler interventions 2. Choice trials: ­ Maze junction transit time (reflects choice time) ­ Heart rate in arm

Heart rate in maze arm ab, p<0.01 b a

Restlessness in maze arm ab, p<0.01 b b a a

Number of stops ab, p<0.01 b b a a

Maze junction transit time - choices

Heart rate in maze arm - choices

Discussion - noise  These results suggest that dairy heifers prefer to avoid exposure to milking parlour noise if given the opportunity  Noise may affect: — time to enter the milking facility — ease of moving animals for handlers — restlessness of animals in the parlour

Discussion - method  Heifers showed an increasing tendency to choose the quiet arm  This was slow to develop in some heifers. —Learning time, or —original bias for choosing the noise arm (first side chosen)  An original maze arm bias may also explain the increased choice times and reduced HR in those animals that continued to choose the noise arm.

Acknowledgements  This research was funded by Dairy Australia  PhD Supervisors: Paul Hemsworth, Ellen Jongman and Kim Ng

Number of handler interventions b ab, p<0.01 b a a