I thought that cattle breeders preferred to mix the best qualities of several stock rather than limit to one gene pool (as in cloning). Most animal breeders (livestock and pet) constantly improve their "product" by refining the features that are bred into each generation. Without introducing new and different genes, the pool becomes stagnent. Cloning might produce an animal with a specific positive attribute but also pass on a specific negative attribute. For example, suppose a cattleman has a complete herd of one cloned cow. Each cow is an outstanding milk producer. However, each cow also carries a certain gene that is susceptible to a specific virus, but the cattleman doesn't know that because the original cow was never exposed to that virus. Well, one day, his cows are exposed to that virus, and the whole herd is wiped out. He has no stock left. Hmmm....
