Amasaib E O, Fadel-Elseed A M, Mahala A G and Fadlelmoula A A 2011: Seasonal and parity effects on some performance and reproductive characteristics of crossbred dairy cows raised under tropical conditions of the Sudan. Livestock Research for Rural Development. Volume 23, Article #78. Retrieved , from http://www.lrrd.org/lrrd23/4/amas23078.htm