Sounds as if the new owner of the cattle has a sound reason for what he is doing. Not only is it not morally wrong, based on the scant information you provide it was probably the only ethical thing to do given the business circuмstances. The sale of the cows was probably necessary on the part of the seller and the purchase of the cows will ultimately provide the means of life to many people who both buy the meat and to the people who work for him.
The only issue that could have any moral implications here is whether the drugs involved will have any negative impact on the quality and healthiness of the meat produced.
I do, however, understand why, given the moral crassness of society today, the word and the thought of what happened would cause anguish. My mother used to say that she had an abortion between her 2nd and 3rd child. She had been a nurse during WWII and what we now call a miscarriage was often called, especially in the medical establishment, an abortion. Induced abortions, after all, were illegal and considered medically unethical and, frankly, unthinkable. Medically speaking, at the time, any pregnancy that terminated before birth was called an abortion. It took me a while, but she finally stopped using the "A-word" because it could be misunderstood.
Unfortunately, though I can explain why, intellectually, it is ok, I can't help you to understand, emotionally, why it is ok. I will pray for you to understand and accept what was necessary.