eli5 Why do cows produce so much milk while pregnant? Instead of producing milk only after birth to feed their young? Does it have to do with the fact that they’re pregnant every year so their body is trying to produce milk for their previous offspring?

Question

eli5 Why do cows produce so much milk while pregnant? Instead of producing milk only after birth to feed their young? Does it have to do with the fact that they’re pregnant every year so their body is trying to produce milk for their previous offspring?

In: Biology

Answer 1

Generally if you keep on taking milk the cow will continue to produce it.

BUT even though you could try and maintain a cow to continue producing a lot of milk, production tapers off anyway due to weather, hormones, feed, temperature, time of year.

The natural process is that as an animal is weaning then milk production slows down. By continually taking milk you effectively bypass the weaning part.

The whole process follows a yearly cycle :

Autumn – very low milk. drying cows off for wintering, impregnating for next season

Winter – cows growing calf inside them, sitting around doing nothing.

Spring – calves born, first milk, high quality feed produces high milk volume

Summer- continue to milk, milk volume tapering off, less good feed available.