Serum levels of reproductive hormones and ultrasonographic monitoring of ovarian follicles in female cloned dogs

This study investigated the reproductive characteristics in 2 cloned female beagle dogs (Clones A and B) during proestrus and early estrus. The pre-ovulatory estradiol peak occurred 2 days before the pre-ovulatory luteinizing hormone (LH) surge, while the follicle stimulating hormone surge started concomitantly with the LH surge in both cloned dogs. Serum progesterone levels increased during proestrus and estrus and its concentration on the day of the LH surge was 3.59 and 2.71 ng/ml in Clones A and B, respectively. Gradual follicular growth was observed by ultrasonography during proestrus. Although the numbers are limited, these cloned female dogs showed normal ranges of reproductive hormone levels and follicular changes during proestrous and early estrous stages of the cycle.