1. Dairy Science Department, National Research Centre, Giza, Egypt
2. Department of Animal Sciences, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
3. Department of Animal Science, University of Abuja, Abuja, Nigeria
4. High Agriculture School of Mograne, University of Carthage, Tunisia
5. Department of Animal Production, Faculty of Agriculture, New Valley University, New Valley, Egypt
6. Department of Animal, Veterinary and Food Sciences, University of Idaho, Twin Falls, ID, USA