Induction of ovarian activity and ovulation in an induced ovulator, the maned wolf (<I>Chrysocyon brachyurus</I>), using GnRH agonist and recombinant LH

Abstract

Assisted reproductive techniques, such as ovarian manipulation and artificial insemination (AI), are useful for enhancing genetic management of threatened wildlife maintained ex situ. In this study, we utilized non-invasive fecal hormone monitoring to investigate (1) the influence of pairing with a male on endocrine responses of female maned wolves (Chrysocyon brachyurus) to a gonadotropin releasing hormone agonist (deslorelin) and (2) the efficiency of recombinant luteinizing hormone (reLH) on ovulation induction in females housed alone. Deslorelin (2.1 mg Ovuplant®) was given to females that were either paired with a male (n = 4) or housed alone (n = 7); the implant was removed 7 to 11 d post-implantation. Three of seven singleton females were injected with reLH (0.0375 mg) on the day of implant removal, while the remaining females (n = 4) did not receive the additional treatment. Fecal samples were collected 5-7 d/wk from all females starting 11 d prior to hormone insertion until at least 70 d post implant removal for a total of 11 hormone treatment cycles. Fecal estrogen and progestagen metabolites were extracted and analyzed by enzyme immunoassay. Evidence of ovulation, demonstrated by a surge of estrogen followed by a significant rise in progestagen, occurred in all paired females. Three of the four singleton females that did not receive reLH treatment exhibited no rise in progestagen following an estrogen surge. All singleton females treated with reLH exhibited a rise in fecal progestagen following injection, indicating ovulation. In conclusion, deslorelin is effective at inducing ovarian activity and ovulation in paired female maned wolves; however exogenous reLH is needed to induce ovulation in females housed alone. The findings obtained from this study serve as a foundation for future application of AI to enhance genetic management of this threatened species ex situ.