The biological activities (health of the animals and the diseases they are exposed to) are no different from small to large. It is easier to monitor and manage

The biological activities (health of the animals and the diseases they are exposed to) are no different from small to large. It is easier to monitor and manage the health of the family cow than a large herd. Mind you, automation these days goes a long ways to mitigating that complexity. Still, having a large herd in close quarters (twice a day they're all coming in to be milked) means exposure risks go up exponentially. The same issues come up in meat production. See antibiotics employed to keep large herds healthy - where healthy is a low bar meaning 'not sick'.