Painting animals can be challenging because most artists want to evoke the character and personality of the animal in the painting. This requires close observation of the real animal, good research photos and careful attention to details that are cues for personality, behavior, mood and attitude. No two cows are alike, so as you paint you need to show a cow's distinction and make its stance and look unique.
Use a sketch pad to draw several cattle sketches using the reference photos you have. Move animals around, change their position and learn their proportions until you can tell what is wrong with their shape and fix it. Create a composition that places the cattle exactly where you want.
Draw your composition on your watercolor paper paying attention to details of face, stance and body proportion. Keep your pencil lines light but easy for you to see.
Paint the eyes of the most prominent cow first. The eye should fit the scale of the cow's face and convey emotion. Paint each cow eye from the largest to the smallest taking the same care with each. Return to the main cow and paint in the eyelid and eyelashes. Add these details on the other cow heads that can be seen.
Paint the dark colors on the cow heads next. Pay attention to the bone structure and use variations of the color to highlight the bones to make the cow head look real. Add dark paint in the same color family to the body of the main cow and then to each other cow in order of size. As animals move further in the distance, the details become less refined.
Return to the primary cow face and detail the nose, ears and horns (if applicable). Touch up other details of the face if some need to be made stronger. Move on to the other cows. On the next pass use a light color wash to indicate the lighter colors on the cow. Use variations of tone to highlight muscles, bones and light and dark shadows. At this point the cows should begin to look dramatic and interesting.
Finish the remaining details of hooves, tails and any part of the cow that needs detailing. Stand back from the painting to assess how it is looking. Some painters use a masking liquid around the outline of the animals to prevent paint from the background from wicking into the finished animals. This would be applied at this point and allowed to dry.
Paint the background starting with the sky, the distance and then the foreground. Layer the paint in to build up the background with the same care you gave the cows. Add details in the final layering to include fences and foreground details of plants. Allow the painting to sit and dry for several days before evaluating if any details need to be intensified.
Watercolor painting with details requires a top-grade watercolor paper that can hold up to lots of water. Some areas of paint can be removed, but it is better to reduce painting errors and add layers rather than disturb the surface of the paper.