"Sheep milk" refers to the milk that is produced by sheep, similar to how cows produce milk. It is a type of milk that comes from sheep, not from cows or goats. Full definition
In addition, there's a big difference between goat milk and cow milk, between sheep milk and goat milk. (kefir.net)
Homemade formula made using sheep milk yogurt which is becoming more available across North America and around the world. (thehealthyhomeeconomist.com)