My calf is 10 weeks old right now. About a month ago his hair was thinning all over some, and he lost a strip about 3 inches long on his spine where it was completely bare. I treated him with ivomec subq every 10 days and his third shot of ivomec was a few days ago. Today I noticed that his hair is thinning again, especially along his spine. I'm not sure what to do at this point and am really confused that it's back after it had stopped almost right away with his first dose of ivomec. Any help would be greatly appreciated.