Can you ask *Who* feeds the calves? If the answer is going to be "Their mother", which is obviously the cow i.e. an animal

Humans are funny. We like to think we're the crown of creation, but we're fixated on associating with others and finding patterns. One of the first things a baby learns to do is recognize the faces of the people who lean over them in the cradle. We're so fixated on making friends and recognizing faces that we often personnify anything that has a "face", usually animals we keep as pets, but often livestock and sometimes even inanimate objects, like a child's doll or Wilson from the movie Castaway. The more human-like traits our brains recognize in something, the more likely we are to treat it like a human.It shouldn't surprise anyone when someone slips up and refer to Alexa or Siri as "she".

In English this results in people using pronouns, usually reserved for people, for animals and the occasional clock. But which animal gets to be called "who" and which one "that" is going to vary greatly from individual to individual.

Think about this exchange between neighbors about a pet's misbehavior:

Neighbor #1:"If that dog poops on my lawn again, I'll shoot it!"

Neighbor #2: "Don't you dare shoot Mr. Barksalot! He's such a sweet little fluffy puppy!"

However, you're also misusing the word "feed" here. A cow doesn't "feed" a calf, it (she) nurses one.