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

It’s purposeful selective breeding. Cattle is domesticated aurochs (the wild species is extinct now). Wild animals looked something like this [https://en.wikipedia.org/wiki/Aurochs#/media/File:Aurochsfeatures.jpg](https://en.wikipedia.org/wiki/Aurochs#/media/File:Aurochsfeatures.jpg)

Here’s a record breaking dairy cow [https://www.farmanddairy.com/news/holstein-cow-sets-national-milk-record-of-77480-pounds/392855.html](https://www.farmanddairy.com/news/holstein-cow-sets-national-milk-record-of-77480-pounds/392855.html)

As you can see, the size of the udder is very much not a natural feature.