Location: Livestock Behavior ResearchTitle: Can prenatal social stress impact sex characteristics in piglets? Author
Submitted to: Joint Abstracts of the American Dairy Science and Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2011
Publication Date: 7/11/2011
Citation: Mack, L.A., Eicher, S.D., Johnson, A.K., Lay Jr, D.C., Richert, B.T., Pajor, E.A. 2011. Can prenatal social stress impact sex characteristics in piglets?. Joint Abstracts of the American Dairy Science and Society of Animal Science. Proceedings. Interpretive Summary:
Technical Abstract: Prenatal stress (PNS) alters sex traits in rodents by androgenizing offspring resulting in reduced reproduction. In production, gestating sows are often exposed to social stress of mixing. This study examined if mixing gestating sows alters sexual development in piglets. At 34 ± 10 d of gestation, 6 groups of 18 sows (N = 108) were put in 1 of 4 treatments: stable (S), hydrocortisone acetate (HCA), unstable (U) or unstable companion (UC). In an incomplete block design, 18 sows were housed in 6 pens of 3 sows for 3 wk. Each pen contained 3 S, 3 HCA, or 1 U and 2 UC sows. Stable, HCA, and UC sows did not move; unstable sows moved weekly into a new pen with unknown UC sows. To simulate stress, 70 mg HCA was orally given twice daily to HCA sows for 3 wk. Data were analyzed in SAS using Mixed Model Procedure. Cortisol concentration was greatest in HCA sows (P < 0.0001) and after initial mixing (P < 0.05). Sows’ progesterone level did not differ by treatment or time. Lesion scores increased after mixing in all treatments (P < 0.05). On wk 3, U sows had more head and upper leg lesions than the other treatments (P < 0.05). Sow’s treatment had little effect on piglets: litter size, sex ratio, BW, and mortality did not differ. Pigs were weighed on d 1, d 3, weaning (d 19 ± 8), and 5 mo post-weaning (6 mo). There was no treatment effect on weight from birth to weaning but at 6 mo HCA and UC pigs tended to weigh more (P < 0.10) and from weaning - 6 mo had greater ADG than S pigs (P < 0.05). Testes weight, teat number, and teat asymmetry did not differ by treatment or gender. Males born from dominant sows, defined by feeding behavior, tended to have more teats than those of low ranked sows (P < 0.10). Anogenital distance (ANO) in male pigs was greater in UC than U pigs (P < 0.05) with the other treatments intermediate. Female ANO showed no differences. Social stress induced by weekly mixing had little impact on sexual, morphological measures of the offspring in this study.