title: Effect of a GnRH analogue (Maprelin) on the reproductive performance of gilts and sows.
abstract: The ability of peforelin (l-GnRH-III) to stimulate follicular growth, FSH release, and estrus in gilts after altrenogest treatment and in sows after weaning was investigated. In three farrow-to-wean herds, with at least 600 sows and average production performance, 216 gilts, 335 primiparous, and 1299 pluriparous sows were randomly allocated to three treatments: peforelin (M group: Maprelin), eCG (F group: Folligon), and physiological saline solution (C group). Animals were treated 48 hours after their last altrenogest treatment (gilts) or 24 hours after weaning (sows). The weaning-to-estrus interval, estrus duration, estrus rate (ER), pregnancy rate, and total born (TB), live born, and stillborn (SB) numbers were recorded and compared between treatments for the different parity groups (gilts and primiparous and pluriparous sows). Follicle sizes were measured in representative animals from each group on the occasion of their last altrenogest treatment or at weaning, and also on the occasions of their first (FS1) and second (FS2) attempted inseminations. Blood samples were taken to determine FSH concentrations at weaning and 2 hours after injection, and progesterone concentrations 10 days after the first insemination attempt. The relative change in FSH concentrations was calculated. Significant differences were found for ER within 7 days of weaning in pluriparous sows (95%, 91%, and 90% for the M, F, and C groups, respectively, P = 0.005). Gilts in the F-group had high TB numbers, and pluriparous sows in the M group had high SB numbers (TB gilts = 13.6, 15.4, and 14.9 [P = 0.02] and SB pluriparous sows = 1.8, 1.4, and 1.7 [P = 0.05] for the M, F, and C groups, respectively). The M group had the highest FS1 (for gilts) and FS2 (for pluriparous sows) values: FS1 = 5.4, 4.9, and 4.9 mm [P = 0.02] and FS2 = 6.8, 5.3, and 6.3 mm [P = 0.03] for the M, F, and C groups, respectively. There were no significant differences between the different treatments within each parity group with respect to any of the other variables. Overall, peforelin treatment had small but positive effects on the ER and follicle growth in certain parity groups but did not seem to affect litter sizes or FSH and progesterone levels in sows on the occasions of the corresponding examinations.
authors.affiliation: Department of Reproduction Obstetrics and Herd Health, Unit Porcine Health Management, Faculty of Veterinary Medicine, University of Ghent, Merelbeke, Belgium. Electronic address: ellen.dejong@dgz.be.
authors.forename: Ellen
authors.initials: E
authors.lastname: de Jong
authors.forename: Johannes
authors.initials: J
authors.lastname: Kauffold
authors.forename: Silke
authors.initials: S
authors.lastname: Engl
authors.forename: Jan
authors.initials: J
authors.lastname: Jourquin
authors.forename: Dominiek
authors.initials: D
authors.lastname: Maes
mesh_terms: D000818:Animals; D004971:Estrus / Q000187:drug effects; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000627:therapeutic use*; D006080:Ovarian Follicle / Q000000981:diagnostic imaging / Q000187:drug effects; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary; D018873:Pregnancy Rate; D011374:Progesterone / Q000097:blood; D012098:Reproduction / Q000187:drug effects*; D013552:Swine / Q000502:physiology*; D014204:Trenbolone Acetate / Q000031:analogs & derivatives / Q000627:therapeutic use; D014463:Ultrasonography
chemical_list: C023445:altrenogest; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D005640:Follicle Stimulating Hormone; D014204:Trenbolone Acetate
keywords: Estrus; Gonadotropins; Peforelin; Sows