There are 2 situations most most beautiful (in my opinion) when painting cows: 1) the early morning 2) late afternoon.
At those moments the light is such that the white cows turn purple aqua blue in the shadows. Or when they're just lit in such a way their bodies turn to those blueish colors.
Yes, warms are needed as well, bellies reflecting the grass, and ochres are in the bluer areas. Have fun with that!!
Here we arrived seeing that. A golden light stroking the cow. Big bodies near turning blue/purple. Of course the cows were again not listening to my demands "Stay, stay!!" But I got that backlit situation in. The grasses so highlighted. And could paint one cow nearer, having a bit of that effect in.
I have a vlog episode about painting cows here
If you're interested in learning about how I create my Cows/Landscape Paintings, I've created an online painting course 'Painting Landscapes With Cows' ► find it here
Recently I also added an IN THE FIELD class (in Holland) for artists who want to paint the landscape + cows from life ► find this here