Follicle dynamic of Girolando heifers synchronized with different P4 intravaginal devices (0,558g or 1.9g) maintained for 8 or 9 day

The aim of this study was to analyze the follicle dynamic of heifers in a protocol of ovulation synchronization using intravaginal device containing different P4 concentrations and different period of maintenance to determine if will be disparity between both. Cyclic Girolando heifers (n = 48) were randomized in one of four groups (factorial 2 x 2): Fertilcare8 (n = 12), Fertilcare9 (n = 12), CIDR8 (n = 12) e CIDR9 (n = 12). Groups Fertilcare8 and CIDR8 received a intravaginal P4 device [Fertilcare®(0.558g) and a second use CIDR (1.9g), respectively] and 2mg of estradiol benzoate (BE) i.m. (Gonadiol®; Zoetis, Sao Paulo, Brazil) on D0 of the TAI protocol . On D8, device was removed and administered 1mg of estradiol cypionate (EC) i.m. (ECP®; Zoetis, Sao Paulo, Brazil) and 0.5mg of sodic cloprostenol (Ciosin ®, Sao Paulo, Brazil). Groups Fertilcare9 and CIDR9 received a intravaginal P4 device [Fertilcare®(0.558g) and second use CIDR (1.9g), respectively] and 2mg of estradiol benzoate (BE) i.m. (Gonadiol®; Zoetis, Sao Paulo, Brazil) on D0. On D7, were injected with 0.5mg of sodic cloprostenol (Ciosin ®, Sao Paulo, Brazil)and on D9 device was removed and administered 1mg of estradiol cypionate (EC) i.m. (ECP®; Zoetis, Sao Paulo, Brazil). The heifers of all protocols were inseminated 48 hours after the devices was removed. Ovary scan by ultrasound were performed at time 0 (considering the moment of device removal), 24, 48, 60, 72, 84 and 96 h. Statistical analysis were performed using the proc GLIMMIX of SAS and data are presented by mean ± SE. Significance is considered when P 0.05), the ovulatory follicle diameter (12.58 ± 0.66 mm vs 13.21 ± 0.49 mm; P > 0,05) the percentage of ovulation by protocol ( 77.27% vs 95.40%; P > 0.05), the time of ovulation after removal of the device (74.82 ± 4.05 hours vs 80 ± 2.66 hours; P > 0.05) , follicle size at the time of withdrawal of progesterone device (9.56 ± 0.86 mm vs 10.79 ± 0,52; P > 0.05) , follicle size on artificial insemination (11.02 ± 0.69 mm vs 13.38 ± 0.62 mm; P > 0.05) and daily growth rate of each dominant follicle (0.95 ± 0.28 mm / day vs 1.29 ± 0.14 mm / day; P > 0,05) . Thus it is concluded that there was no statistical difference between the protocols of 3 managements or the 4 managements protocol when it was used the second use progesterone CIDR® and even when we used the progesterone single dose device Fertilcare® then both protocols being effective for ovulation synchronizing on heifers.