You have beautiful horses!
I really love how this camera picks up depth and color, and I really like your sense of balance/composition. The only thing that I think could use a little work is the lighting, but it's a new camera and you're using natural lighting in the evening, when there's only really a small frame of time where it's the best, so don't worry. ;) I usually just edit with GIMP to get the shine out of black coats/ lighten and darken photographs. Not a fan of heavy editing, so usually I only mess with color/contrast/ etc a bit.
The ones I really like overall are the 8th one and 12th. I love the color and lighting in the background of the first, too!