I wonder if today's epidemic of depression isn't in part fueled by the consumption of milk from grieving cows.

That distress has to get into the milk; this is one of the pathways of epigenetic regulation -- meaning the distress is heritable, and may impact cross-species.

And it is a completely unneccessary practice. See https://ec.europa.eu/eip/agriculture/en/find-connect/project...

On this farm, calves are kept with cows for 5 months after birth.