*Ralf’s joke.
Not many people notice this, but goats’ eyes have rectangular pupils, long horizontal ones with proper 90-degree corners, almost like a horse’s eye:
This is Askur's eye. There's very little contrast between the rectangular pupil and its dark-brown surround; however, if you know it's there I think you can see it.
… only more pronounced.
It makes you wonder what things look like to a goat. Different, that’s for sure. They get very lost and confused about which direction to go when they come to a fence. It’s not a sign to them as it is to us. We think: if you can’t climb over it, follow the fence until you come to a gate. To them it seems to be a hidden surface they can’t penetrate — almost like a sheet of glass. Despite their difficulty, if you hang around with goats they’ll draw your attention to a lot of things which you’d normally miss: other animals moving about, mostly. It comes from their having to watch out for predators creeping up on them, and Stu in the last post pointed out that goats have very good peripheral vision. Have I mentioned this before: goats don’t seem to have terribly good night vision? They are said to be afraid of the dark — quite reasonably, they are often surrounded by mortal enemies — so at dusk they sit down and don’t move until it gets light again.
Two of our goats have brown eyes, but Holly has eyes like a cat’s: they’re both yellow and blue at the same time without blending into green.
Holly's eye
A Bad Guide 
Anyone’s who’s seen Albee’s Who Is Sylvia? should be familiar with the shape of the goat’s pupil.
Interesting, though. I can’t claim to have ever looked a cow deep in the eye, but I recall them as being pretty ordinarily round. I wonder what the evolutionary advantage has been.
I’m not sure about cows’ eyes. With the horse I had to take a picture, it wasn’t apparent just by looking at his eye. I ‘ll have to take a picture of a cow’s eye.