title: Effect of intrauterine treatment with prostaglandin E2 prior to insemination of mares in the uterine horn or body.
abstract: Two trials were conducted to investigate the effects of intrauterine infusion of PGE2 and uterine horn insemination on pregnancy rates in mares achieved by breeding with a suboptimal number of normal spermatozoa. Estrus was synchronized and mares were teased daily with a stallion to detect estrus. Mares in estrus were examined by transrectal palpation and ultrasonography to monitor follicular status. On the first day a 35-mm diameter follicle was present, hCG (1500 IU, iv) was administered and the mares were bred the next day. Mares (Trial 1, n = 34; Trial 2, n = 28) were inseminated with 25 million total spermatozoa from either a stallion with good semen quality (Trial 1) or poor semen quality (Trial 2). In each trial, mares were assigned to 1 of 4 treatment groups as follows: Group PGE-HI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; Group PGE-BI - infusion of 0.25 mg PGE2 into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body; Group SAL-HI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the proximal end of the same uterine horn; or Group SAL-BI - infusion of 1 mL sterile saline into the proximal end of the uterine horn ipsilateral to the dominant follicle 2 h prior to insemination in the uterine body. After breeding, mares were examined daily by transrectal ultrasonography to confirm ovulation, and were re-examined 14 to 16 d after ovulation for pregnancy status. Data were analyzed by Chi-square. Overall pregnancy rates were 59% for stallion 1 and 29% for stallion 2. Group pregnancy rates did not differ for mares bred by either stallion (P > 0.10). Pregnancy rates were not altered by horn insemination for either stallion (P > 0.10). Intrauterine infusion of PGE2 improved pregnancy rate in mares bred by the stallion with good quality semen (P < 0.05), but did not alter pregnancy rate in mares bred by the stallion with poor quality semen (P > 0.10). Further research is warranted to determine if intrauterine infusion of PGE2 will enhance spermatozoal colonization of the oviduct and pregnancy rates in mares, and if PGE-treatment will improve pregnancy rates achieved by subfertile stallions.
authors.affiliation: Department of Large Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station 77843-4475, USA.
authors.forename: J
authors.initials: J
authors.lastname: Woods
authors.forename: S
authors.initials: S
authors.lastname: Rigby
authors.forename: S
authors.initials: S
authors.lastname: Brinsko
authors.forename: R
authors.initials: R
authors.lastname: Stephens
authors.forename: D
authors.initials: D
authors.lastname: Varner
authors.forename: T
authors.initials: T
authors.lastname: Blanchard
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000008:administration & dosage; D015237:Dinoprost / Q000008:administration & dosage; D015232:Dinoprostone / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D004958:Estradiol / Q000502:physiology; D004973:Estrus Synchronization; D005260:Female; D006736:Horses / Q000502:physiology*; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000502:physiology; D011897:Random Allocation; D012098:Reproduction / Q000502:physiology*; D012661:Semen / Q000502:physiology; D013081:Sperm Motility / Q000502:physiology; D016216:Ultrasonography, Prenatal / Q000662:veterinary; D014599:Uterus / Q000187:drug effects / Q000502:physiology*
chemical_list: D006063:Chorionic Gonadotropin; D011374:Progesterone; D004958:Estradiol; D015237:Dinoprost; D015232:Dinoprostone