Anti-Müllerian Hormone in the Domestic Dog during the Anestrus to Oestrous Transition.

The reproductive cycle of the domestic dog features a long period of relative ovarian inactivity or anestrus. The mechanism of anestrous termination/oestrous resumption is not yet fully understood, which presents a challenge to the development of oestrous induction protocols. In this study, we assess the possibility that anti-Müllerian hormone (AMH) might play a role in this transition by characterizing its patterns of expression in the circulation during the transition from anestrus to oestrous and in all stages of ovarian follicular growth. Serum samples from five beagles (2.0-4.5 years) were collected three times per week at least 30 days prior to the onset of oestrous and assessed for AMH concentrations. Serum AMH concentration increased significantly during the transition from anestrus to proestrus and then declined back to the anestrous baseline beginning on day -4 before the luteinizing hormone surge, which was determined by changes in serum progesterone concentrations. Cortical sections of ovaries from females undergoing routine ovariohysterectomy (aged 8 months-5 years, n = 4) were evaluated for AMH by immunohistochemistry. Pre-antral and small antral follicles were most strongly immunoreactive for AMH. These data suggest that the increase in the number of antral follicles is associated with the rise in serum AMH as the anestrous period comes to an end. The rise in AMH might be useful in predicting the onset of oestrus and therefore assist with the optimization of oestrous induction protocols and possibly other assisted reproductive technologies.

The Domestic Dog Embryo: In Vitro Fertilization, Culture, and Transfer.

Advances in embryo technologies in the domestic dog have made significant strides in the past decade. This progress has been spurred by interests in taking advantage of the dog as a biomedical research model for human and companion animal medicine, developing assisted reproductive technologies to manage genetic diversity in endangered canids maintained ex situ, and improving breeding in rare or working breeds of dogs. Here, we focus on recent advancements and techniques for collection of in vivo-matured oocytes, in vitro fertilization (IVF), in vitro culture of early (≤8-cell) and advanced stage (≥16-cell) embryos, and embryo transfer.