RESUMO
The treatment of cystic ovarian disease (COD) in dairy cows is still controversial, and some researchers recommend using gonadotropin-releasing hormone (GnRH) regardless of the type of cysts. The aim of this study was to comparatively evaluate the reproductive performance of cows diagnosed with follicular or luteal cystic structures, after treatment with either buserelin acetate (GnRH agonist) or dinoprost (prostaglandin F2-alpha or PGF2α). The diagnosis was established by ultrasonographic examinations performed twice a month starting 40-45 days after calving, until the cows were diagnosed pregnant after artificial insemination. Both types of cysts were treated either with 21 µg buserelin acetate or 25 mg dinoprost, resulting in four subject groups. After treatment, the estrus rate in cows with follicular cysts treated with dinoprost (55.1%) was significantly lower (P<0.05) than in cows treated with buserelin acetate (77.5%) or in cows diagnosed with luteal cysts (77.2% for dinoprost and 72.4% for buserelin acetate). The conception rate was higher (P<0.05) in cows with follicular cysts treated with buserelin acetate (67.7%) than in those treated with dinoprost (60%) or in those with luteal cysts (56.9% for dinoprost and 47.5% for buserelin acetate). These results show that it is preferable to differentiate between the two types of ovarian cysts before treatment. Luteal cysts can be treated with either PGF2α or GnRH analogues, with better results when PGF2α is used. Contrastingly, follicular cysts are better treated with GnRH analogues. When differentiation is not possible, GnRH analogues are recommended over PGF2α.
