Effect of dietary energy source on energy balance, production, metabolic disorders and reproduction in lactating dairy cattle Ariëtte T.M. van Knegsel, Henry van den Brand, Jan Dijkstra, Seerp Tamminga and Bas Kemp Reprod. Nutr. Dev., 45 6 (2005) 665-688 DOI: 10.1051/rnd:2005059