Insemination protocols of artificial evaluation in fixed time for cattle Curraleiro Pé-Duro

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, 2016.O estudo teve como objetivo verificar a resposta fisiológica de fêmeas da raça Curraleiro Pé- Duro submetidas a diferentes protocolos de sincronização e indução da ovulação, buscando-se o aumento da eficiência reprodutiva. Três experimentos foram realizados para avaliar o melhor momento de indução da ovulação e o tempo de exposição à progesterona. No Experimento 1, 12 vacas receberam um dispositivo intravaginal de progesterona (P4) e 2 mg de benzoato de estradiol (BE) intramuscular (IM) no dia zero (D0). Após oito dias (D8) os animais tiveram o implante de P4 removido e receberam 150 μg de D-cloprostenol Sódico (PGF2α) e 300 UI de gonadotrofina coriônica equina (eCG) via IM, sendo então separadas em dois grupos. Grupo 8D (n=6), as vacas receberam 1mg de BE IM no D8, e no grupo 9D (n=6), receberam BE no D9. No Experimento 2, cinco vacas foram submetidas ao mesmo protocolo usado no Grupo 9D do Experimento um, e seis vacas no D8 receberam 150 μg de PGF2α e 300 UI de eCG e no D9 receberam 1 mg de BE e tiveram o dispositivo de P4 retirado (Grupo P4D9). Em ambos os experimento, após a retirada do implante de P4 foram realizadas avaliações ovarianas ultrassonográficas. No Experimento 3, 88 matrizes foram submetidas aos protocolos utilizados nos grupos 8D (n=43) e P4D9 (n=45) e inseminadas em tempo fixo. No Experimento 1, os grupos 8D e 9D levaram a uma taxa de sincronização do folículo dominante de 92% (11/12) e 83% (10/12) e uma taxa de ovulação de 73% (8/11) e 100% (10/10), respectivamente. O tempo para ovulação após a retirada da P4 foi menor nas fêmeas do 8D. No Experimento 2, os grupos 9D e P4D9, levaram a uma taxa de sincronização do folículo dominante de 72% (8/11) e 100% (11/11), respectivamente e a uma taxa de ovulação de 87,5% (7/8) e 91% (10/11), não havendo diferença nos demais parâmetros foliculares estudados. No experimento 3, a taxa de gestação nos grupos 8D e P4D9 foram de 23% (10/43) e 20% (9/45; P>0,05) respectivamente. Conclui-se que, os protocolos utilizados neste trabalho tiveram resultados de desenvolvimento folicular satisfatórios, mas não refletiram em uma boa taxa de prenhes após inseminação artificial em tempo fixo (IATF). Nesse contexto, há necessidade de mais estudos em relação à fisiologia reprodutiva das fêmeas Curraleiro Pé- Duro e quanto à aplicação de protocolos de IATF para animais desta raça.This study aimed to determine the physiological response of locally adapted females Curraleiro Pé-Duro race under different synchronization protocols and ovulation induction, evaluating the efficiency of these, as well as the determination of ovulation time, ovulatory follicle size, emergency wave and finally the pregnancy rate of females submitted to TAI programs. In one experiment, all females (n=12) on day zero (D0) received an intravaginal device containing 1g of progesterone (P4) which remained for eight days and 2 mg of estradiol benzoate (EB) intramuscular (IM). After that the animals were randomly divided into two groups; 8D treatment (n=6) and 9D treatment (n=6). On removal day of the implant P4 (D8) cows in the 8D group received IM 150 μg of Sodium D-cloprostenol, 300 IU eCG and 1 mg of EB. In 9D treatment group the cows had the implant removed in D8 and received IM 150 μg of D-cloprostenol Sodic and 300 IU eCG, and in contrast to the control group, the animals received IM in D9 1mg EB. The treatments differed among themselves as to the BE application day. For the second experiment, all animals (n=11) in D0 received the same pharmacological treatment of the previous experiment and were randomly divided into two groups; 9D treatment (n=5) and P4D9 treatment (n=6). The animals 9D treatment group had P4 implant removed in D8 and received IM 150 μg of D-cloprostenol Sodic and 300 IU eCG, and D9 received IM, 1mg EB. In contrast the P4D9 treatment group the females received D8 IM 150 μg of D-cloprostenol Sodium and 300 IU eCG and D9 were removed P4 implant followed by IM administration of 1mg of EB. The treatments differed on the withdrawal time of P4 implants. In both experiments, on the P4 implant removal day was also initiated ovarian ultrasound assessment every 24h up to 24h after removal of the P4 implant. After this period, the evaluations were performed every 8 hours for up to 96 hours in the attempt to monitor from the FD to the ovulation. Experiments one and two occurred in crossover format. For the third experiment we used the protocols for the treatment 8D and P4D9 to TAI. Where, for the 8D treatment group (n=43) insemination occurred in the period of 40/42 hours and P4D9 for the treatment group (n=45) 24/26 hours after removing the P4 implant. For the experiment one, the 8D and 9D treatments led to a sync rate of the dominant follicle 92% (11/12) and 83% (10/12) and ovulation rate of 73% (8/11) and 100% (10/10), respectively. There was no effect of treatments on group and interaction day VS group (P> 0.05) in follicular development, only daily growth (P0,05). As for the three experiments where animals were submitted to TAI, it is found to 8D treatment group and P4D9 treatment group pregnancy rates of 23% (10/43) and 20% (9/45) respectively (P>0,05), concluding that there is still need for more studies on the reproductive physiology of females Curraleiro Pé-Duro, is the hormonal and ultrasonographic control of follicular development, or the development of new methodologies in TAI specific protocols for animals of this breed