Effect of intravaginal fluorogestone acetate sponges on prolactin levels of Damascus-local cross breed goats

Abstract

The effect of intravaginal fluorogestone acetate (FGA) sponges on prolactin levels (PRL) and correlations between PRL and milk somatic cell count (SCC) and steroid hormones levels of Damascus-local cross goats during transitional period to anestrous were investigated in this study. Fifty-six goats were assigned to three groups. Group 1 (FGA, n = 19) was treated with 40 mg FGA and equine chorionic gonadotropin (600 IU, i.m.) at time of sponge withdrawal (day 0). Group 2 (FGA-PGF; n = 19) was treated similar to group 1 but was also injected with dinoprost tromethamine (naturally occurring PGF2α) (10 mg, i.m.) on day 0. Control goats (n = 18) were left untreated. On day 0, five fertile bucks were turned in with all goats. Milk and blood samples were collected on days -13 (day of sponge insertion), -6, 0, 1, 2, 7, 13, and 20. Prolactin levels were at lowest values on day -13 of the study and increased (p < 0.05) from day -6 to day 20 in all groups. A significant positive correlation (p < 0.05) between PRL and progesterone and between PRL and estradiol levels was found in this study. No significant correlation was found between PRL and SCC of all groups during the study except on days 2 and 20 where PRL levels were correlated (p < 0.05) with SCC of left udder halves of FGA group. In conclusion, estrus induction with FGA resulted in significant increase in PRL. A positive correlation was found between PRL and steroid hormones, but there was no correlation between PRL and goat milk SCC.

Reproduction in Goats

“…The synchronization of estrus in goats by medroxyprogesterone acetate (MAP) or fluorogestone acetate (FGA) sponges has been accomplished in many advanced countries in the world [22]. Most commonly, progestogen-/progesterone-impregnated vaginal devices and subcutaneous progestogen implants followed by an injection of equine chorionic gonadotropin ((eCG), formerly PMSG), were used for estrous synchronization [23]. However, a prolonged progestagen treatment is also associated to reduced fertility (related to a subluteal serum progesterone concentration at the end of treatment) [24].…”

“…This acts by promoting the growing and persistence of the dominant follicle which causes detrimental effects on fertility. Reduced fertility in prolonged progestagen-treated females may be also related to an impairment of sperm transport in the genital tract [23,24].…”