Correlação entre o diâmetro do folículo pré-ovulatório e a eficiência reprodutiva em vacas Bos taurus indicus submetidas à inseminação artificial em tempo fixo

O presente estudo objetivou avaliar o diâmetro do folículo ovariano pré-ovulatório (FPO) no momento da IATF em vacas multíparas Bos taurus indicus correlacionando-o com a taxa de concepção (TC). Foram utilizadas 145 vacas, paridas até 65 dias, e submetidas a único protocolo: no dia 0 (d0) implante de 1,0 g de progesterona + aplicação de 2,0 mg de benzoato de estradiol; em d8 remoção dos implantes e aplicação de 500 µg de D-Cloprostenol + 300 UI de Gonadotrofina coriônica equina e 1,0 mg de cipionato de estradiol; no d10 mensurou-se o FPO (ultrassom) e procedeu-se a IATF com sêmen congelado. No d35 pós IATF realizou-se o diagnóstico de prenhez. A taxa de concepção à IATF foi de 62,7% e o diâmetro médio do FPO nas vacas prenhes foi de 15,1mm, e de 13,7mm nas vazias (P=0,03). Foram estabelecidos 04 estratos relativos ao diâmetro dos FPOs (mm): 8,0 a 11,0; 11,1 a 14,0; 14,1 a 17,0 e 17,1 a 20,0, resultando respectivamente em 37,0; 75,7; 66,6 e 72,7% de TC. Estratificou-se ainda o diâmetro do FPO em £11,0 mm e ³ 11,1 resultando em TC de 36,8% e 72,0% (P 11,1mm constituem forte indicativo de maior eficiência reprodutiva.

Impact of Equine Chorionic Gonadotropin Associated with Temporary Weaning, Estradiol Benzoate, or Estradiol Cypionate on Timed Artificial Insemination in Primiparous Bos Indicus Cows

The study aimed to determine the impact of equine chorionic gonadotropin (eCG) associated with different timed artificial insemination (TAI) protocols on the pregnancy rate (PR) in Bos indicus cows previously treated with progesterone. Five hundred and fifty-seven primiparous cows were subjected to the following treatments: on day 0 (d0), GeCGTW (group equine Chorionic Gonadotropin+Temporary Weaning;n=178) received 0,558 g intravaginal progesterone (P4)+1.0 mg of estradiol benzoate (EB) (IM); on d8 (P4 removal+0,075 mg D-cloprostenol + 400 IU eCG + TW for 48 h); on d10, TAI + calves return to dam; GeCGEB (group equine Chorionic Gonadotropin+Estradiol benzoate; n=176) the same as GeCGTW without TW + application of 1.0 mg of EB on d9; GeCGEC (group equine Chorionic Gonadotropin+Estradiol Cypionate; n=203), the same as GeCGTW without TW+1.5 mg EC (IM). On d35, post TAI, pregnancy diagnosis (PD) was performed. Non-pregnant animals remained under clean-up bulls for 90 days. After this period, the animals were subjected to PD using ultrasound. The PR of TAI was 51.1%, 47.1%, and 47.8% for GeCGTW, GeCGEB24, and GeCGEC (P>0.05) respectively. The PR under clean-up bulls was 88.3%, 47.3%, and 31.1% (P<0.05). The final PR (TAI+clean-up bulls) of the groups was 94.4%, 72.1%, and 64.0%, respectively (P<0.05). It was concluded that no differences in PR among the protocols related to TAI were detected; PR in the GeCGTW protocol under clean-up bulls was higher compared to others (P<0.05); the overall PR of cows subjected to TAI+clean-up bulls was significantly higher in GeCGTW than in the other groups