title: Effects of a single administration of prostaglandin F2alpha, or a combination of prostaglandin F2alpha and prostaglandin E2, or placebo on fertility variables in dairy cows 3-5 weeks post partum, a randomized, double-blind clinical trial.
abstract: BACKGROUND
  Delayed uterine involution has negative effects on the fertility of cows; use of prostaglandin F2alpha alone as a single treatment has not been shown to consistently improve fertility. Combined administration of PGF2alpha and PGE2 increased uterine pressure in healthy cows. We hypothesized, that the combination of both prostaglandins would accelerate uterine involution and have, therefore, a positive effect on fertility variables. In commercial dairy farming, the benefit of a single post partum combined prostaglandin treatment should be demonstrated.
  
  
  METHODS
  383 cows from commercial dairy farms were included in this study. Uterine size and secretion were evaluated at treatment 21-35 days post partum and 14 days later. Cows were randomly allocated to one of three treatment groups: PGF2alpha and PGE2, PGF2alpha or placebo. For every animal participating in the study, the following reproduction variables were recorded: Interval from calving to first insemination, days open, number of artificial inseminations (AI) to conception; subsequent treatment of uterus, subsequent treatment of ovaries. Plasma progesterone level at time of treatment was used as a covariable. For continuous measurements, analysis of variance was performed. Fisher's exact test for categorical non-ordered data and exact Kruskal-Wallis test for ordered data were used; pairwise group comparisons with Bonferroni adjustment of significance level were performed.
  
  
  RESULTS
  There was no significant difference among treatment groups in uterine size. Furthermore, there was no significant difference among treatments concerning days open, number of AI, and subsequent treatment of uterus and ovaries. Days from calving to first insemination tended to be shorter for cows with low progesterone level given PGF2alpha and PGE2 in combination than for the placebo-group (P = 0.024).
  
  
  CONCLUSIONS
  The results of this study indicate that the administration of PGF2alpha or a combination of PGF2alpha and PGE2 21 to 35 days post partum had no beneficial effect upon measured fertility variables. The exception was a tendency for a shorter interval from calving to first insemination after administration of the combination of PGF2alpha and PGE2, as compared to the placebo group. Further research should be done in herds with reduced fertility and/or an increased incidence of postpartum vaginal discharge.
authors.affiliation: Clinic for Ruminants, Vetsuisse Faculty of the University of Berne, Bremgartenstrasse 109a, 3012 Berne, Switzerland. gaby.hirsbrunner@knp.unibe.ch
authors.forename: Gaby
authors.initials: G
authors.lastname: Hirsbrunner
authors.forename: Heinz W
authors.initials: HW
authors.lastname: Burkhardt
authors.forename: Adrian
authors.initials: A
authors.lastname: Steiner
mesh_terms: D000818:Animals; D002417:Cattle; D015237:Dinoprost / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D015232:Dinoprostone / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004311:Double-Blind Method; D004357:Drug Synergism; D005260:Female; D005298:Fertility / Q000187:drug effects*; D007315:Insemination, Artificial / Q000662:veterinary; D009929:Organ Size / Q000187:drug effects; D049590:Postpartum Period / Q000187:drug effects*; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D014599:Uterus / Q000187:drug effects* / Q000502:physiology; D019522:Vaginal Discharge / Q000188:drug therapy
chemical_list: D011374:Progesterone; D015237:Dinoprost; D015232:Dinoprostone