Cows and women both fall under the spell of an amazing love drug every time they produce milk: oxytocin. As a breastfeeding mother, I know the dreamy feeling that it brings first-hand and the cows might just enjoy the same sensation in the dairy.
Oxytocin triggers the “let down” reflex amongst other things (sexual arousal included!) but its action is pretty much blocked by stress hormone, adrenaline.
This is really obvious in the dairy. We make sure there aren’t too many people in the dairy, avoid shouting or having barking dogs nearby and even keep the radio on the same station. Upset the routine at all and the cows start to get jumpy. And that means lots of cow poo and golden showers plus a very slow milking coupled with less milk in the vat.
So, if you visit your local dairy farmer, try not to get too excited in the shed. Walk slowly and gently and, if you must make noise, make it a lullaby.