Way different scenario dude. Here you have cows being bread to support specific genes naturally to cows. Even selectively breeding can cause serious health effects to the animal - take a look at the extreme examples in dogs and their health related issues based on bread. However, even in these extreme examples of cross breading such as the super cows, Belgian Blues, I'm sure they are safe to consume if no genetic engineering in a lab was done.
With GMO, you can cross bread species. You could take a salmon and cross bread it with a reptile, amphibian, mammal, plant - take your pick. The code is corrupted. Take a look at the research done in England. Scientists proved that body can recognize chemicals such as pesticides and eliminate a good amount of it. However, with GMO, the body cannot figure this one out and eventually the animals that ate the GMO foods developed very serious health problems, including death.