title: Ovulation rate and litter size in gilts immunized against androstenedione and 17alpha-hydroxyprogesterone.
abstract: Two experiments were conducted to evaluate the effects of the immunization of gilts against ovarian steroids on ovulation rate and litter size. In Exp. 1, gilts (n = five gilts/treatment) at 165+/-1.6 d of age were immunized against either carrier (Control), androstenedione, or 17alpha-hydroxyprogesterone. Age at puberty and estrous cycle length averaged 208+/-5.5 (P = 0.67) and 20.3+/-2.8 d (P = 0.41), respectively, and were not affected by treatment. The androstenedione- and 17alpha-hydroxyprogesterone immunized gilts had higher (P < 0.02) ovulation rates than Controls (14.2, 14.2, and 11.4+/-0.8, respectively). Total pigs born (P = 0.66) and pigs born live (P = 0.65) for the androstenedione-treated group were not different from Controls. Gestation length was not different (P = 0.36) between any of the treatments and the Controls (115+/-0.9 d). Procedures used in Exp. 2 were similar to those in Exp. 1, except that only Control (n= 18) and 17alpha-hydroxyprogesterone (n = 16) treatments were included and only litter size at farrowing was measured. Total pigs and pigs born live were higher in the 17a-hydroxyprogesterone-treated gilts than in the Controls (12.6 vs 10.5+/-0.6, P < 0.02; and 11.4 vs 9.2+/-0.6; P < 0.01, respectively). Data from this study indicate that litter size in gilts can be increased by immunization against 17alpha-hydroxyprogesterone.
authors.affiliation: Department of Animal Science, University of Arkansas, Fayetteville 72701, USA. dkreider@uark.edu
authors.forename: D L
authors.initials: DL
authors.lastname: Kreider
authors.forename: R
authors.initials: R
authors.lastname: Rorie
authors.forename: D
authors.initials: D
authors.lastname: Brown
authors.forename: C
authors.initials: C
authors.lastname: Maxwell
authors.forename: F
authors.initials: F
authors.lastname: Miller
authors.forename: S
authors.initials: S
authors.lastname: Wright
authors.forename: A
authors.initials: A
authors.lastname: Brown
mesh_terms: D019326:17-alpha-Hydroxyprogesterone / Q000276:immunology*; D000735:Androstenedione / Q000276:immunology*; D000822:Animal Husbandry / Q000379:methods; D000818:Animals; D005260:Female; D007114:Immunization / Q000662:veterinary*; D008098:Litter Size / Q000276:immunology*; D010060:Ovulation / Q000276:immunology*; D011897:Random Allocation; D013552:Swine / Q000276:immunology / Q000502:physiology*
chemical_list: D000735:Androstenedione; D019326:17-alpha-Hydroxyprogesterone