3Marsteller TA, Armbruster GA, Anderson D B, et al. Effect of lactation length on ovulation rate and embryo survival in swine [J]. Swine Health Prod, 1997, 5:49-56.
4encing Knox RV. Zas SL. Factors infiu estrus and ovulation inweaned sows as sound [J] determined by transrectal ultra J AnimSci. 2001.79:2957-2963.
5Smith AL, Stalder K J, Serenius TV, et al. Effect of weaning age on nursery pig and sow reproductive performance [J]. J Swine Health Prod, 2008, 16(3):131-137.
7Belstra BA, Diekman MA BT. Effects of lactation length and ogenous progesterone and Richert an ex- estradi- ol- 17beta regimen during embryo attach- ment on endogenous steroid concentra- tions and embryo survival in sows[J]. The- riogenology, 2002, 57(8):2063-2081.
8Pope WF.Embryonic mortality in swine. In:Zavy M T, Geisert R D, editors. Embryonic mortality in domestic animal species [M]. Boca Raton, FL: CRC Press, 1994:53-77.
9Le Cozier Y J, Dagorn J, Dourmad Y, et al. Effect of weaning-toconception nterval and lactation length on subsequent tter size in sows [J]. Livest Prod Sci, 1997.
10Tantasuparuk W, Lundeheim Dalin AM.Effects of lactation length and weaning- to- service interval on subse- quent farrowing rate and litter size in Lan- drace and Yorkshire sows in Thailand [J] Theriogenology, 2000, 54(9):1525-1536.
4Levast B, de Monte M, Chevaleyre C, et al. Ultra-early weaning in piglets results in low serum IgA concen- tration and ILl7 mRNA expression[J]. Vet Immunol Immunopathol, 2010,137 (3-4) : 261-268.
5Poletto R,Steibel J P,Siegford J M, et al. Effects of early weaning and social isolation on the expression of glucocorticoid and mineralocorticoid receptor and 11 beta-hydroxysteroid dehydrogenase 1 and 2 mRNAsin the frontal cortex and hippocampus of piglets[J]. Brain Res ,2006,1067(1) :36-42.
6Kanitz E,Puppe B,Tuchscherer M,et al. A single ex- posure to social isolation in domestic piglets activates behavioural arousal,neuroendocrine stress hormones, and stress-related gene expression in the brain[J]. Physiol Behav, 2009,98 (1-2) : 176-185.
7Matteri R L,Dyer C J,Touchette K J, et al. Effects of weaning on somatotrophic gene expression and circu- lating levels of insulin-like growth factor-1 (IGF-1) and IGF-2 in pigs [J]. Domest Anim Endocrinol, 2000,19(4) : 247-259.
8Mathews L S, Enberg B, Norsredt G. Regulation of rat growth hormone receptor gene expression[J]. J Biol Chern, 1989,264(17) :9905-9910.
9Mertani H C, Morel G. In situ gene expression of growth hormone (GH) receptor and GH binding pro- tein in adult male rat tissues[J]. Mol Cell Endocri- nol, 1995,109 (1) : 47-61.
10Herrington J, Carter-Su C. Signaling pathways activa-ted by the growth hormone receptor[J]. Trends En- docrino! Metab ,2001,12(6) :252-257.
