How do you ask a cow what makes her happy?

 

My paper “Sprinkler flow rate affects dairy cattle avoidance of spray to the head, but not overall, in an aversion race” is in the current issue of Applied Animal Behaviour Science.

I’m looking forward to presenting this study as a poster at this year’s congress of the International Society for Applied Ethology in Edinbugh. It’s the society’s 50th anniversary, and it looks to be a big and exciting gathering this year!

You may have seen ads that describe California’s dairy cows as being “happy.” This alludes to the idea that welfare includes not only an animal’s physical, but also their emotional well-being.

When cows are exposed to summertime heat, this can result in problems for both milk production and animal welfare. An effective way to keep cows cool is to spray them with water. But if spray is good for them, why do cows sometimes avoid sprinklers?

Understanding this was one of the goals of my dissertation research. Higher-volume sprinklers use more water, which cools cows better, to a certain extent. Cows might find better cooling to be more rewarding. However, with higher-volume sprinklers, the spray is more intense, and the water hits the cows with greater impact. Do cows find this sensation unpleasant?

In this study, I tested how cows respond to higher- and lower-volume sprinklers. The way I quantified how willing the cows were to approach sprinklers was with an “aversion race,” which has been used with many species in other studies. We required each cow to walk through a long and narrow alley to approach the sprinklers. The idea is that once the cows learn what is at the end of the alley, when you test them repeatedly, they will approach rewarding things more quickly and willingly, and unpleasant things more slowly and reluctantly.

I found that when cows approached the higher-volume sprinklers, they ducked their heads, as if to avoid getting them wet. Why would cows avoid exposing their heads to spray? I tested how sensitive the cows’ heads were compared to their torsos, using von Frey hairs. Their heads were more sensitive, which might explain why cows avoided spray directed towards their heads.

Head

However, the cows didn’t seem reluctant to approach the spray altogether. This could be because they only had to walk through the spray – and get their heads wet – briefly. So in the future, I hope to examine whether cows find it unpleasant when they have to stand with their heads under spray for longer periods. That type of situation is not uncommon, since many farms use overhead sprinklers in the holding pen where cows wait before they are milked.

If we can provide sprinklers in a manner that cows will use willingly, this could benefit not only their physical  well-being by improving cooling, but also their emotional well-being by not exposing them to things they find unpleasant.

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