The coloring is nice but it looks like it has a few anatomical errors to me. I was going to go into an explanation but I think a visual would help better xD

The hip/rump needs to be higher up for the position it's in. If you notice on the photo, if you take the legs and straighten out the joints to have it's back legs more or less straight, the rump is much higher and makes more of a hill than a straight, gentle curve and is higher than the back. Also, the proportions of the shoulder/hip to the body are off. The hip is slightly wider than the shoulder but the overall body length is about four shoulder lengths in total, which can be applied to most quadriped animal's proportion-wise. The neck also seems like it needs to be slightly thicker and with a little more inward curve as it reaches the main body, and the chest needs to be a little more pronounced, since it does stick out a bit further than the shoulder

Also, the chin should be a little more pronounced and the head a bit longer, I think.\
Also, if you do the width of the body from belly to back, it's about three body-width's tall from hoof to the top of the head/neck.
Hope that information helps
