Deslorelin acetate (Ovuplant) therapy in cycling mares: effect of implant removal on FSH secretion and ovarian function.
Following induction of ovulation with deslorelin acetate (Ovuplant), gonadotrophin concentrations are reduced in the subsequent cycle, leading to increased interovulatory intervals in some mares. This study determined whether implant removal after 2 days prevented the decrease in gonadotrophin concentrations and follicular growth during the ensuing cycle. Twenty-four mares were randomised equally into 3 groups. Group 1 ovulated spontaneously, Groups 2 and 3 received the deslorelin implant to induce ovulation. Two days after treatment, the implant was removed from Group 3. On Day 10 postovulation, FSH was lower (P = 0.009) in Group 2, but not different between Groups 1 and 3. Follicular diameter on Day 14 was less (P<0.05) in Group 2 (19.0 +/- 2.1 mm) than in Groups 1 and 3 (36.6 +/- 2.5 and 30.5 +/- 2.0 mm, respectively). Interovulatory interval was longer (P<0.05) for Group 2 (25.8 +/- 2.9 days) compared to Groups 1 and 3 (18.5 +/- 0.7 and 19.4 +/- 0.3 days, respectively). Removal of the deslorelin implant eliminated the decreased FSH secretion and the increased interovulatory interval associated with implant administration. Therefore, it is recommended that the implant be removed after ovulation is detected to prevent the occurrence of a prolonged interovulatory interval.
Equine Reproduction Laboratory, Colorado State University, Fort Collins 80523, USA.
V J
VJ
Farquhar
P M
PM
McCue
E M
EM
Carnevale
T M
TM
Nett
E L
EL
Squires
D000818:Animals; D004343:Drug Implants; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D006062:Gonadotropins / Q000097:blood; D006736:Horses / Q000097:blood / Q000502:physiology*; D006080:Ovarian Follicle / Q000187:drug effects* / Q000502:physiology; D010060:Ovulation / Q000187:drug effects; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary*; D011897:Random Allocation; D013997:Time Factors; D017329:Triptorelin Pamoate / Q000031:analogs & derivatives
D004343:Drug Implants; D004791:Enzyme Inhibitors; D006062:Gonadotropins; D017329:Triptorelin Pamoate; D007987:Gonadotropin-Releasing Hormone; D005640:Follicle Stimulating Hormone; C066438:deslorelin