5Audet I, Berube N, Bailey JL, et al Effects of dietary vitamin in supplementa- tion and semen collection frequency on reproductive performance and semen quality in boars [J]. Anim Sci, 2009,87(6): 60-70.
4Lindermann M D,Wood C M,Haroer A F.Dietary Chromium Picolinate Additions Improve Gain/Feed and Carcass Characteristics in Growing-Finishing Pigs and in Creased Litter Size in Producing Sows[J].J Anim Sci,1995,7(3):457.
5Almeida F R C L,Kirkwood R N,Aheme F X,et al. Consequences of different patterns of feed intake during the estrous cycle in gilts on subsequent fertility[J].J Anita Sci,2000,78:1556-1563.
6Almeida F R C L, Mao J, Novak S, et al. Effects of different patterns of feed restriction and insulin treatment during the luteal phase on reproductive,metabolic and endocrine parameters in cyclic gilts[J]. J Anita Sci,2001, 79:200-212.
7Ashworth C J,Antipatis C,Beattie L.Effects of pre- and postmating nutritional status on hepatic function,progesterone concentration,uterine protein secretion and embryo survival in Meishan pigs[J]. Reprod Fertil Dev, 1999,11 ( 1 ) :67-73.
8Cox N M. Control of follicular development and ovulation rate in pigs[J]. J Reprod Fertil, 1997,52 (Suppl):31-46.
9Foxcroft G R.Mechanisms mediating nutritional effects on embryonic survival in pigs[J]. J Reprod Fertil, 1997,52 (Suppl) :47-61.
10Geisert R D, Schmitt R A M. Early embryonic survival in the pig: can it be improved [J]. J Anita Sci,2002,80(E Suppl1) : E54-E65.