"Veterinarians who started their practice after GMOs were introduced in 1996 might assume that many chronic or acute animal disorders are common and to be expected. But several older vets have stated flat out that animals have gotten much sicker since GMOs came on the scene. And when they switch livestock from GMO to non-GMO feed, the improvement in health is dramatic. Unfortunately, no one is tracking this, nor is anyone looking at the impacts of consuming milk and meat from GM-fed animals."
Here's a link to one of the papers published by Dr. Huber, who's quoted in the article above.