Muldoon,
I don't really notice the difference in masculinity in heifers that I have implanted. If they haven't been implanted very long then you can still feel it in their ear. I don't implant heifers until weaning so that I can pick out the ones I plan on keeping or selling as replacements and don't implant them. It says on the information for ralgro that you can implant heifers once when they are young and it will not affect their reproductiveness. I believe it is basically a mix of testosterone and estrigen so if a heifer has been implanted hard and heavy she may show masculinity traits and not look as feminine.
Ann,
Please don't take this personal, it is just my opinion. I see your point - but - the use of implants are going to happen regardless of what anyone thinks, until implants are taken off of the market and are not produced anymore. I just don't see that happening. There are products used in every single market; beef, dairy, poulty, swine, fruit, vegetable (short of any organics) that do or at least have the potential to cause health problems, cancer, stroke, obesity and death in humans. Look at how many people out there light up thoses cigaretes multiple times a day knowing full well that they are going to get cancer from them. How many people drive through fast food restaurants EVERY DAY knowing full well that they are going to get FAT from it. Do they stop? No! They may think about it then super size their meals and then just do it again tomorrow and the next day and the next day. People are getting fat in America because of the abundance of easy to get food that is high in calories and fat and their lack of self control, not the implants some producers are putting in calves.