Dairy cows don’t pose. You might think they hold still when you see them placidly grazing in a field, but the minute you set up to sketch them, they start moving around like chipmunks.
If you want to paint them from life, the key is to organize the palette. For these Holsteins, I pre-mixed a dark gray and a black for their dark spots, and a couple of light tones for their white areas. I kept a separate brush for each tone.
I quickly drew their shapes with a brush on the 8 x 10 inch panel, which was oil primed with a tint of burnt sienna. Then I dove in with the tones.