Effects of Combined Estradiol-Sulpiride Treatment and Follicle Ablation on Vernal Transition in Mares: Evaluation of Plasma and Follicular Fluid Hormones and Luteinizing Hormone Receptor Gene Expression

Sucrose acetate isobutyrate (SAIB) as a delivery vehicle for estradiol and sulpiride: Evaluation of endocrine responses in geldings and ovarian response in seasonally anovulatory mares

Sulpiride in vegetable shortening (VS) stimulates prolactin in horses for up to 10 days. Although effective, a pharmaceutical grade vehicle is needed for clinical application of sulpiride in horses. Sucrose acetate isobutyrate (SAIB), a hydrophobic polymer, may be an alternative to VS. Four in vivo experiments assessed the efficacy of SAIB for delivery of sulpiride, estradiol cypionate (ECP), and estradiol benzoate (EB). The first three studies utilized geldings to compare prolactin and luteinizing hormone (LH) concentrations between sulpiride delivered in VS and SAIB, and ECP or EB delivered in SAIB. Sulpiride stimulated (P < .01) prolactin similarly between vehicles. Geldings pre-treated with EB had higher (P < .05) prolactin responses to sulpiride compared to ECP-treated geldings on days 5, 6 and 9. Both estradiol-sulpiride treatments stimulated LH with no differences between ECP and EB. Experiment 3 compared a simultaneous injection of EB-sulpiride to a non-simultaneous injection (one day apart) of EB-sulpiride. Prolactin was stimulated (P < .05) in both treatment groups, but the response lasted 2 days longer in geldings treated a day apart. Plasma LH increased (P < .01) in both groups equally for 10 days. Experiment 4 applied simultaneous and non-simultaneous EB-sulpiride treatments to seasonally anovulatory mares to induce ovarian activity. Prolactin and LH were stimulated similarly between treatments; however, non-simultaneously treated mares tended (P = .07) to have an ovarian response earlier. In conclusion, SAIB was a suitable vehicle for administration of estradiol and sulpiride and could be an alternative to VS for sustained-release drug delivery.

Hormonal Management for the Induction of Luteolysis and Ovulation in Andalusian Jennies: Effect on Reproductive Performance, Embryo Quality and Recovery Rate

Two prostanglandins (luprostiol, LUP, and dinoprost, DIN) and two ovulation-inducing agents (human Chorionic Gonadotropin, hCG, and deslorelin, DES) were evaluated for luteolysis and estrus induction, and for ovulation induction, respectively, in embryo donor jennies. Twenty-six fertile Andalusian jennies were used. In Experiment 1, jennies (n = 112 cycles) were randomly treated with either LUP or DIN after embryo flushing. In Experiment 2, donors (n = 84 cycles) were randomly treated with either hCG or DES to induce ovulation. No differences were found between prostaglandins for all variables studied (prostaglandin–ovulation interval (POI), interovulatory interval (IOI), embryo recovery rate (ERR), positive flushing rate (PFR) and embryo grade (EG)). The ovulation rate was similar for hCG and DES (60.9% vs. 78.7%). However, the interval to ovulation (ITO) was affected (62.61 ± 7.20 vs. 48.79 ± 2.69 h). None of the other variables studied (ERR, PFR and EG) were affected (p > 0.05), except for embryo quality (p = 0.009). In short, both prostaglandins evaluated are adequate to induce luteolysis and estrus. Both ovulation-inducing agents hastened ovulation, but DES seems to be more effective than hCG. Follicular diameter affected the interval from treatment to ovulation, and high uterine edema was related to low embryo quality.