2Lelanc S J, Leslie K E, Duffield T F. Metabolic predictors of displaced abomasum in dairy cattle[J]. J Dairy Sci, 2005, 88: 159-170.
3Overton T R, Waldron M R. Nutritional management of transition dairy cows: strategies to optimize metabolic heahh[J]. J Dairy Sci,2004, 87: 105-119.
4Melendez P, Risco C A, Donovan G A, et al. Effect of calciumenergy supplements on calving-related disorders, fertility and milk yield during the transition periodin cows fed anionic salts[J]. Theriogenology, 2003, 60: 843-854.