Population-based anti-Müllerian hormone reference intervals help define gonadal status in the bitch

Area of Science:

• Veterinary endocrinology
• Reproductive biology
• Canine health

Background:

• Accurate interpretation of canine anti-Müllerian hormone (AMH) requires established population-based reference intervals (RIs).
• Understanding hormonal fluctuations during the canine reproductive cycle is crucial for accurate gonadal status assessment.

Purpose of the Study:

• To establish statistically valid, population-based reference intervals (RIs) for canine AMH.
• To define the cyclic changes of AMH and inhibin-B in female dogs (bitches) during their breeding cycles.

Main Methods:

• A homologous canine ELISA was employed to measure AMH in serum samples from intact and ovariohysterectomized (OVH) bitches.
• Longitudinal samples from bitches undergoing breeding management were analyzed for AMH and inhibin-B (using a heterologous ELISA).
• Established RIs were retrospectively applied to 3,193 clinical submissions for AMH testing.

Main Results:

• Population-based RIs for AMH in intact and OVH bitches were calculated.
• Canine AMH and inhibin-B levels were positively correlated, with AMH concentrations being threefold higher during proestrus compared to estrus.
• Retrospective analysis indicated that 41% to 56% of clinical submissions fell within or above the intact AMH RI, while 37% to 44% were within the OVH RI.

Conclusions:

• Statistically valid, population-based RIs provide a reliable basis for interpreting clinical AMH results in bitches.
• Cyclic variations in AMH and inhibin-B confirm proestrus as the optimal time for sample collection for gonadal status assessment.
• An estimated 10% or fewer of samples submitted for gonadal status determination are expected to yield inconclusive AMH results.