One of my ewes is slightly lame again.She does have a habit of going lame. I've had the vet to her when she was very lame and he couldn't find any thing wrong.I caught her up yesterday and had a good look at her feet. Nothing looks like foot rot as I've seen in books but her feet did smell a bit unpleasant.I'm going to foot bathe with zinc sulphate and give her an antibiotic injection, using L.A. Alamycin. Would one injection be sufficient or should I give her a course over several days? Thank you.