Estradiol-17β Injection Induces Ovulation in Llamas

Differential Effects of Estradiol on Reproductive Function in Camelids

“…The results of Bianchi et al ( 10 ) are consistent with previous studies in other induced ovulators. In rabbits, administration of a combination of estrogen and progesterone daily for 2 days, but not estrogen or progesterone independently, led to ovulation in 40% of synchronized does ( 12 ).…”

“…In California voles, administration of estradiol-17β or estradiol benzoate caused ovulation in up to 28% of treated females ( 13 ). In these studies, however, assessment of the ovulatory response was based on single examinations (laparotomy or post-mortem), while Bianchi et al ( 10 ) used a non-invasive approach (ultrasonography and blood sampling) that allowed clear characterization of corpus luteum form and function. Despite the limited information available in scientific literature, results point out the possibility that camelids, and other induced ovulators, may elicit an LH surge in response to both estradiol and NGF.…”

“…The results from Bianchi et al ( 10 ) are exciting since estradiol may be stimulating neuronal pathways to trigger a GnRH and LH surge in camelids in addition to providing support for the effects of NGF ( 11 ). Based on rabbit studies ( 14 ), the principal factor driving hypothalamic discharge of GnRH into the portal vessels in induced ovulators is the conduction of physical coital stimuli via spinal cord transmission of action potentials.…”

“…In a recent report ( 10 ), the effects of estradiol-17β administration on ovulation and luteal development in llamas were examined. Administration of increasing concentrations of estradiol-17β (0.6, 1, and 1.6 mg/llama) increased the ovulatory rate in an incremental manner (0/4, 1/4, and 6/6, respectively).…”

“…Thus, it was suggested that estradiol promotes the fullness of the pre-ovulatory LH surge induced by NGF. The report from Bianchi et al ( 10 ), however, is the first to directly test the effects of estradiol on ovulation in llamas.…”