2DeFrain J M,Hippen A R, Kalscheur K F,et.al.Feeding glycerol to transition dairy cows: effeets on blood metabolites and lactation perfor- mance[J].J Dairy Sci,2004,87:4195-4206.
3Drackley J K. Biology of dairy cows during the transition period: the final frontier[J].J Dairy Sci, 1999,82:2259-2273.
4Grummer R R.Impact in changes in organic nutrient metabolism on feeding the transition cow[J]. J Anita Sci. 1995,73:2820-2833.
5Guo J,Peters R R, Kobll R A.Effeet of a transition diet on production performance and metabolism in periparturient dairy cows [J].J Dairy Sci.2007,90:5247-5258.
6Hayirli A,Grummer R R,Nordheim E V, et.al.Animal and dietary fac- tors affecting feed intake during the prefresh transition period in Hol- steins[J].J Dairy Sci.2002,85: 3430-3443.
7Mandebvu P, Ballard C S, Sniffen C J, et.al.Effect of feeding an ener- gy supplement prepartum and postpartum on milk yield and composi- tion, and incidence of ketosis in dairy cows [J].Anim Feed Sci Tech. 2003,105:81-93.
8McNamara S,O'Mara F P,Rath M, et.al.Effects of different transition diets on dry matter intake, milk production, and milk composition in dairy cows[J].J Dairy Sci.2003,86:2397-2408.
9Park A F,Shirley J E,Titgemeyer E C,et.al.Effect of protein level in prepartum diets on metabolism and performance of dairy Cows [J].J Dairy Sci.2002,85:1815-1828.
10Pickett M M,Piepenbrink M S,Overton T R.Effects of propylene glycol or fat drench on plasma metabolites, liver composition, and production of dairy cows during the periparturient period [J].J Dairy Sci.2003,86: 2113-2121.
