Comparing the Vitex-castus extract and cabergoline effects on estrous induction in female dogs

Cabergoline is used to induce estrus, stop lactation, and induce abortion in small animals. The specific doses of Vitagnus extract have almost identical properties of cabergoline that reduce prolactin and increase the concentration of FSH hormone. The aim of this study was to compare the effect of Vitex agnus-castus extract and cabergoline on prolactin concentration and hormonal changes associated with the onset of estrous cycle in dogs. Twelve healthy adult cyclic female-mix breed dogs were selected and randomly aligned in treatment (6 dogs, Vitagnus extract 1.5 ml daily for 5 weeks, 80–90 mg/ml, PO) and control groups (6 dogs, cabergoline, daily for 5 weeks, 5 μg/kg, PO). Blood sampling and vaginal smears were taken weekly. Serum samples were stored at −20 °C until prolactin, estradiol, and progesterone were measured by ELISA method. Based on vaginal cytology results, four (cabergoline) and three (Vitagnus) dogs were in the estrous phase after 5 weeks of treatment. The average concentration of the prolactin was not changed during 5 weeks and between two groups. There was no significant difference in progesterone and estradiol levels between groups. The changes of estradiol concentration were significant during the 5 weeks (p < 0.01). The mean concentration of this hormone changed significantly between weeks 2 and 3 (p < 0.01), 2 and 5 (p < 0.05), and 3 and 4 (p < 0.05). In conclusion, Vitagnus extract had hormonal effects similar to those of cabergoline for induction of estrus in bitches.