The effect of milking shed noise on dairy cow behaviour using a Y maze

1. 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

2. 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.

3. Noise in the milking parlour • The background sound level in a normal commercial milking facility ranges from 75-85 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?

4. 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

5. 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

6. Procedure Day 0: habituation 3 trials Day 1: training + test 5 trials Day 2: training + test 5 trials Day 3: one-off test 1 trial • For each animal, the noise stimulus was presented in the first arm entered on day 1. • 16 heifers

7. Maze side choice b b b a ab, p<0.01

8. 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

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

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

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

12. Maze junction transit time - choices

13. Heart rate in maze arm - choices

14. 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

15. 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.

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

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