My unprofessional opinion...
She looks longer in pic #3, but she also looks bigger in the brisket than in the others. She looks more broody, with a slightly straighter top line & the rear leg is set better in #1 & #2. Also, she appears to be standing at the best camera angle in pic #2 & I like her head/front better in #2 than in #1. I think that I would go with pic #2, although that wasn't my intial thought because she is zoomed out a little further, so I'd maybe crop it a little bit to zoom in more on the cow. You could try to take some more, but like you, I'm not sure if they will be all that much better if any better.