I don't know it either, but I read it as: - 'goat' referring to both the 'greatest of all time' as in specialized and at the same time to it being a not-so-common animal, - while 'cow' is simply just a common animal, so in this context it represents a plain worker.

I'm not aware of any 'cow' acronym, that would directly relate to work/proficiency as the 'goat' does but it would further enhance the meaning behind the quoted phrase.

In fact it's exactly what is missing, for the phrase to be instantly understandable by making it symmetric in both direct and acronymic reading.

So is there a 'cow' acronym, that is an antonym to 'goat'? I'm not aware of one.

I made it up on the hoof (pun intended)

Cows are the most common animal on the farm, and overall they produce the most value. But they are very replaceable. When times are bad, you slaughter them.

Cows are like your rank-and-file application developers: you scale them up and down with the times.

Goats are more niche. You don't have many of them on your farm. But they solve important problems (eating weeds), and they look after themselves, so you seldom slaughter goats.

Goats are like specialists in your company. People who know how the "real" things operate. You don't need many of them. But they are involved in enough critical things, niches that can't be scaled down, that you seldom lay them off