title: Influence of repeated regrouping on reproduction in gilts.
abstract: It is generally assumed that stress around oestrus and during early pregnancy reduces reproductive performance of pigs. In our experiment, late prepuberal gilts (age at arrival 225+/-6 days) were housed in groups of four. Stress treatment consisted of once weekly regrouping and twice weekly feed competition of the 28 Stress gilts during 6 consecutive weeks, starting 13 days after arrival. Control gilts (n=28) were not treated. During the 0.5-1.5h after regroupings, Stress animals fought consistently more than the Control animals; up to 13 of the Stress animals fought for at most 60% of the time compared to one Control animal fighting for at most 3.3% of the time. The day before first regrouping, gilts had on average 4.0+/-0.9 skin scratches. By week 6, this number had reduced to 2.1+/-1.0 in Control, but remained 4.0+/-1.3 in Stress gilts (P<0.05). In the afternoon after regroupings, skin scratches increased up to 6.3+/-1.6 in the Stress gilts. Saliva cortisol in the afternoon before regrouping did not differ between weeks 1, 3 and 6, nor did it differ between Stress and Control. In Stress gilts, saliva cortisol was increased in the afternoon of first regrouping, in Batch 2 only (from 1.8+/-0.4 to 4.1+/-0.9 ng/ml; P<0.05). Animals showing a second oestrus within 5 weeks after arrival were inseminated. Duration of second oestrus of these animals was 2.48+/-0.66 days in the Stress gilts (n=24) and 2.21+/-0.58 days in the Control gilts (n=22; P>0.10). At Day 35 after insemination, pregnancy rate was 100% in both groups. Ovulation rate and number of total and vital fetuses was similar (P>0.10). The Stress treatment during a 6-week period around insemination consistently resulted in fighting but did not result in long term effects on cortisol levels and did not impair reproductive performance.
authors.affiliation: Animal Sciences Group, Wageningen University, P.O. Box 338, 6700 AH Wageningen, The Netherlands. nicoline.soede@wur.nl
authors.forename: N M
authors.initials: NM
authors.lastname: Soede
authors.forename: M J W
authors.initials: MJ
authors.lastname: van Sleuwen
authors.forename: R
authors.initials: R
authors.lastname: Molenaar
authors.forename: F W
authors.initials: FW
authors.lastname: Rietveld
authors.forename: W P G
authors.initials: WP
authors.lastname: Schouten
authors.forename: W
authors.initials: W
authors.lastname: Hazeleger
authors.forename: B
authors.initials: B
authors.lastname: Kemp
mesh_terms: D000374:Aggression; D000818:Animals; D001522:Behavior, Animal; D004971:Estrus / Q000502:physiology; D005260:Female; D006854:Hydrocortisone / Q000032:analysis; D007315:Insemination, Artificial / Q000662:veterinary; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology*; D012463:Saliva / Q000737:chemistry; D012919:Social Behavior; D013312:Stress, Physiological / Q000503:physiopathology*; D013552:Swine; D013553:Swine Diseases / Q000503:physiopathology*
chemical_list: D006854:Hydrocortisone