1. Center for Food Animal Health, Department of Animal Sciences, College of Food, Agricultural and Environmental Sciences, The Ohio State University, Wooster, OH 44691, USA.
2. Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi, P.O. Box 29053, 00625 Nairobi, Kenya.
3. Department of Animal Production, Faculty of Veterinary Medicine, University of Nairobi, P.O. Box 29053, 00625 Nairobi, Kenya.