1. Faculty of Veterinary Medicine, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
2. Faculty of Animal Production, University of Khartoum, Shambat, 13314 Khartoum North, Sudan
3. Institute of Biosciences, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
4. Institute of Tropical Agriculture, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia
5. Department of Animal Science, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor, Malaysia