Investigation of the effect of repeated use of PRIVD on serum progesterone, estrogen levels, and ovulatory follicle diameter in pubertal heifers

The purpose of this study was to evaluate the effect of reuse of progesterone-releasing intravaginal devices (PRIVDs) on serum progesterone, estrogen levels, and ovulatory follicle diameter in pubertal heifers. Three pubertal Holstein heifers were used in the study for three different periods with the usage of three PRIVDs up to three times from day 0 to 7 according to the Latin square model. Blood samples were collected on days 0, 3, 5, 7, and 9 for hormonal analysis. Ovulatory follicle diameter was measured by transrectal ultrasonography 60 h after removal of the PRIVD. Serum progesterone demonstrated a significant relationship with device use and day (P 0.05) and ovulatory follicle diameter (P > 0.05) did not differ significantly with the use of the PRIVD at day 9. In the present study, even the 3rd use of the PRIVD produced similar results as the first use. In conclusion, PRIVDs can be reused or manufactured with low progesterone for heifers to reduce hormonal synchronization cost.