Efeito da utilização de uma dose adicional de dinoprost trometamina em protocolos de IATF em vacas Nelore
Data
2020-03-19
Autores
Noronha, Isabella Marconato
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi avaliar se vacas Nelore, que receberam duas doses de PGF2α em protocolos de IATF a base de progesterona e estradiol, teriam melhor fertilidade em comparação a uma dose de PGF2α. Foram realizados 2 experimentos em que os animais receberam o protocolo de IATF: dispositivo intravaginal de P4 (CIDR) e 2,0 mg benzoato de estradiol (i.m., 2 ml Gonadiol®, Zoetis), no d-11, dinoprost trometamina (PGF2α; i.m., 2,5 ml Lutalyse®, Zoetis) no d-4, retirada do dispositivo de P4, 0,6 mg de cipionato de estradiol (i.m., 0,3 ml ECP®, Zoetis) e 300 UI de eCG (i.m., 1,5 ml Novormon®, Zoetis) no d-2, e IATF no d0. No experimento 1, as vacas (n=1.039) foram divididas aleatoriamente para receber uma ou duas doses de PGF2α, sendo a primeira no d-4 e a segunda no d-2. No experimento 2, foram avaliadas 1.051 fêmeas Nelore, permanecendo para as análises deste estudo apenas fêmeas que não apresentaram um CL no d-4 (momento da primeira PGF2α; n=934), os tratamentos foram os mesmos descritos no experimento 1. Foi fixado um dispositivo para avaliar a expressão do cio (Estrotect®) no d-2, avaliado o diâmetro folicular no d0, as colheitas de sangue foram realizadas no d0 e d7, para dosagem de P4. O diagnóstico de gestação (DG) foi realizado 30 dias após IA. No experimento 1, a taxa de prenhez foi maior para os animais do grupo 2PG (54,5% vs. 46,6%; P = 0,01) em relação a 1PG. No experimento 2, a taxa de sincronização e a taxa de prenhez foram maiores no grupo 2PG, (81,4% vs. 72,1%; [P= 0,01] e 55,5% vs. 45,6%; [P = 0,04], respectivamente) apenas nos animais com ECC < 5,0 (escala de 1 a 9). Já nos animais com ECC ≥ 5,0, não houve diferença entre os tratamentos. Independente de ECC, não foi observado diferença na taxa de concepção, diâmetro do maior folículo no momento da IA e expressão de cio. Houve interação entre o tratamento e o diâmetro folicular sobre a taxa de sincronização (P= 0,004). Em conclusão, a utilização de duas doses de PGF2α foi mais eficiente em sincronizar folículos menores (< 13,1 mm) e promoveu efeito positivo na taxa de sincronização e prenhez, nas vacas com ECC < 5,0.
The aim of this study was to evaluate whether Nelore cows that received two doses of PGF2α in progesterone and estradiol-based TAI protocols would have better fertility compared to one dose of PGF2α. Two experiments were performed in which the animals received an TAI protocol: intravaginal P4 device (CIDR) and 2.0 mg estradiol benzoate (i.m., 2 ml Gonadiol®, Zoetis) at d-11, dinoprost tromethamine (PGF2α; i.m., 2 , 5 ml Lutalyse®, Zoetis) at d-4, P4 device withdrawal, 0.6 mg estradiol cypionate (i.m., 0.3 ml ECP®, Zoetis) and 300 IU eCG (i.m., 1.5 ml Novormon®, Zoetis) at d-2, and AI at d0. In experiment 1 the animals (n = 1,039) were randomly assigned to receive one or two doses of PGF2α, the first on d-4 and the second on d-2. In experiment 2, 1,051 Nelore cows were used, and remaining for the analysis of this study only females without CL on d-4 (moment of first PGF2α; n=934), the treatments were the same as described in experiment 1. A device was fixed to evaluate estrus expression (Estrotect®) at d-2, measured follicular diameter at d0, blood samples were collected at d0 and d7 for P4 dosage. The pregnancy diagnosis was made 30 days after AI. In experiment 1, the pregnancy rate was higher for animals in group 2PG (54.5% vs. 46.6%; P = 0.01) compared to 1PG. In experiment 2, synchronization rate and pregnancy rate were higher in group 2PG (81.4% vs. 72.1%; [P = 0.01] and 55.5% vs. 45.6%; [P = 0.04], respectively) only in animals with BCS < 5.0 (scale from 1 to 9). In animals with BCS ≥ 5.0, there was no difference between treatments. Regardless of BCS, there was no difference in conception rate, diameter of the largest follicle at the moment of AI, and estrus expression. There was an interaction between treatment and follicular diameter on the synchronization rate (P=0.004). In conclusion, the use of two doses of PGF2α was more efficient in synchronizing small follicles (< 13.1 mm) and had a positive effect on synchronization and pregnancy rates in cows with BCS < 5.0.
The aim of this study was to evaluate whether Nelore cows that received two doses of PGF2α in progesterone and estradiol-based TAI protocols would have better fertility compared to one dose of PGF2α. Two experiments were performed in which the animals received an TAI protocol: intravaginal P4 device (CIDR) and 2.0 mg estradiol benzoate (i.m., 2 ml Gonadiol®, Zoetis) at d-11, dinoprost tromethamine (PGF2α; i.m., 2 , 5 ml Lutalyse®, Zoetis) at d-4, P4 device withdrawal, 0.6 mg estradiol cypionate (i.m., 0.3 ml ECP®, Zoetis) and 300 IU eCG (i.m., 1.5 ml Novormon®, Zoetis) at d-2, and AI at d0. In experiment 1 the animals (n = 1,039) were randomly assigned to receive one or two doses of PGF2α, the first on d-4 and the second on d-2. In experiment 2, 1,051 Nelore cows were used, and remaining for the analysis of this study only females without CL on d-4 (moment of first PGF2α; n=934), the treatments were the same as described in experiment 1. A device was fixed to evaluate estrus expression (Estrotect®) at d-2, measured follicular diameter at d0, blood samples were collected at d0 and d7 for P4 dosage. The pregnancy diagnosis was made 30 days after AI. In experiment 1, the pregnancy rate was higher for animals in group 2PG (54.5% vs. 46.6%; P = 0.01) compared to 1PG. In experiment 2, synchronization rate and pregnancy rate were higher in group 2PG (81.4% vs. 72.1%; [P = 0.01] and 55.5% vs. 45.6%; [P = 0.04], respectively) only in animals with BCS < 5.0 (scale from 1 to 9). In animals with BCS ≥ 5.0, there was no difference between treatments. Regardless of BCS, there was no difference in conception rate, diameter of the largest follicle at the moment of AI, and estrus expression. There was an interaction between treatment and follicular diameter on the synchronization rate (P=0.004). In conclusion, the use of two doses of PGF2α was more efficient in synchronizing small follicles (< 13.1 mm) and had a positive effect on synchronization and pregnancy rates in cows with BCS < 5.0.
Descrição
Palavras-chave
Protocolos de IATF, Vacas Nelore, Dinoprost trometamina, PGF2, TAI protocol, Nelore cows, Dinoprost tromethamine, PGF2α