Nice pup!

On the color question, there is a slight cast, but it is green. Probably due to the light reflecting of the grass and other greenery.

Easy way to check for and remove casts:

Open in PS,
Duplicate the background layer.
Go Filter > Blur > Average (You'll end up with a solid color)
Add a Level Adjustment layer, select the middle gray eyedropper and click on a point in the solid color.

Then, turn off visibility of the solid layer and look at the difference. I find the results are usually great, but when they aren't they are horrible. You can adjust the opacity of the levels layer to have a bit more control of just how much of the cast is removed.

Sometimes a cast is a good thing.