Estudo da dinâmica folicular no protocolo de nove dias de sincronização de cios com o uso de um novo dispositivo de liberação sustentada de progesterona, associado ou não ao eCG, em ovelhas Santa Inês / Study of follicular dynamics during nine day estrus synchronization protocol using a new progesterone sustained release device, associated or not with eCG, in Santa Inês ewes

Marina Berrettini Paes de Barros

The present study aimed the assessment of follicular dynamics in Santa Inês ewes during the nine day estrus synchronization protocol, with or without the administration of eCG, using a new intravaginal silicon device, Primer-PR® (Tecnopec Brasil). In Experiment 1, ten ewes received the vaginal device on D0, which was removed on D9 and received 0,4mL of d-cloprostenol. Ultrasound exams were performed daily, since D-3 of the device placement until D9 and every 12 hours thereafter, until ovulation. During Experiment 1, blood samples were taken from the ewes that received the device (grupo GP, n=10) and the ewes that were in physiological state (grupo GF, n=12). In Experiment 2, nine ewes received the same treatment in Experiment 1 and 250UI of eCG on the day of the device removal. Ultrasound exams for follicular development were performed every 12 hours starting on D9 until ovulation. Blood samples were taken every other day from D-1 until D13. In Experiment 1, follicular emergence occurred in 8,5 days ± 16 hours after the vaginal device placement. The ewes started and ended estrus at, respectively, 45,6 ± 12,71h and 72 ± 12,96h after device removal and ovulation was detected in 73 ± 14,38 h. The mean initial follicle diameter was 3,48 ± 0,28 mm and the mean ovulatory follicle diameter was 5,22 ± 0,72 mm, being statistically different (p=0,006) between the first and second ovulatory follicle and between the first follicle of single ovulation (5,77 ± 0,34mm) or double ovulation individuals (4,83 ± 0,18mm) (P=0,003). The follicular growth rate during this period was 0,73 ± 0,43 (mm/day). In Experiment 2, estrus started at 36 ± 6,4h, ended at 81 ± 8,46h with ovulation occurring in 74,3 ± 7,56 h after the vaginal device removal. The mean initial follicle diameter was 4,04 ± 0,78 mm and the mean diameter ovulatory follicle was 5,40 ± 0,59 mm, differing statistically between the first follicle of single ovulation individuals (5,91± 0,27mm) or double ovulation individuals (5,2 ± 0,22mm) (P=0,007). Follicular growth rate during the period was 0,66 ± 0,43 mm per day. In Experiment 1, Primer-PR® device increased plasmatic progesterone concentration in group GP to 6,56 ± 2,32 ng/mL, whereas physiological group (GF) had 3,8 ± 2,69 ng/mL during the same period. In Experiment 2 plasmatic progesterone concentration throughout the vaginal device use was 11,50 ± 3,11ng/mL. It can be concluded that it was possible to perform ultrasound evaluation of follicular dynamics during the nine day estrus synchronization protocol in Santa Inês ewes and that the new device used was efficient in synchronizing the emergence of ovulatory follicular wave.

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