[Dairy cattle pregnancy rate in fixed time artificial insemination program with and without ultrasonic gynecologic screening.]

To evaluate the pregnancy rate and the importance of ultrasound gynecological screening (US) performed prior to fixed time artificial insemination programs (TAI), 120 Girolando cows, over two breeding seasons (2013 and 2014), were divided into two groups: (C / T; n = 58) and without (S / T; n = 62) gynecological screening by ultrasound, using three protocols, and the same for the groups with and without screening. Protocol I - “OvSynch” (OV) in which received 0.025 mg of buserelin acetate in D0; 0.15 mg d-cloprostenol on D7; 0.025 mg buserelin acetate D9; It is inseminated at fixed time in D10. Protocol II - “OvSynch” + progesterone (OP4) and III Protocol - “OvSynch” + LH + P4 (OP4LH). Protocols II and III followed the same dosages of “OvSynch” associated with the introduction of intravaginal device containing 1g first use of progesterone in D0 and D7 in withdrawal. In Protocol III, LH replaced buserelin acetate in ovulation induction (D9; 25mg). Gestation diagnosis was made by US 45 days after TAI, and the animals not pregnant were reinseminated as presented heat. Parameters pregnancy rate at TAI (TP), total pregnancy rate (TPT = TAI + Return heat) were analyzed by Chi-square or Fisher’s exact with 5% significance level. The use of progesterone favored the pregnancy rate of cyclic and acyclic animals, this has not occurred with LH job as ovulation inductor, providing no increase in pregnancy rates and overall pregnancy rate of dairy cows referred to the rated protocol. The gynecological screening by ultrasonography allowed evaluating the cyclicity of the studied females, indicating that its previous execution to the TAI, can provide good results with the use of better efficiency protocols for TAI programs