A novel strategy for resynchronization of ovulation in Nelore cows using injectable progesterone (P4) and P4 releasing devices to perform two timed inseminations within 22 days

Autor(es)

Pugliesi, Guilherme ^[1] ; Bisinotto, Danilo Zago ^[2] ; Mello, Barbara Piffero ^[2] ; Lahr, Fabio C. ^[2] ; Ferreira, Catia A. ^[1] ; Melo, Gabriela Dalmaso ^[1] ; Bastos, Michele Ricieri ^[3] ; Madureira, Ed Hoffmann ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Vet Med & Anim Sci, Dept Anim Reprod, Pirassununga, SP - Brazil

^[2] Univ Sao Paulo, Sch Anim & Food Sci, Dept Vet, Pirassununga - Brazil

^[3] Ourofino Saude Anim, Cravinhos - Brazil

• Tipo de documento: Artigo Científico
• Fonte: REPRODUCTION IN DOMESTIC ANIMALS; v. 54, n. 8, p. 1149-1154, AUG 2019.
• Citações Web of Science: 0

Resumo

We aimed to evaluate the reproductive performance of Nelore lactating cows submitted to a resynchronization 12 days after timed artificial insemination (TAI) with or without a long-acting progesterone (P4-LA) treatment. Nelore cows were submitted to a P4/oestradiol-based TAI protocol (D0 = insemination). On D12, cows in the control group (n = 184) received a new P4 intravaginal device (0.96 g), whereas cows in the P4-LA group (n = 192) received the P4 device and 75 mg P4-LA. Cows identified as non-pregnant (n = 120) by regression of corpus luteum using colour Doppler ultrasonography on D20 had the P4 device removed and received 500ug of sodium cloprostenol, 1 mg of oestradiol cypionate and 300 IU of eCG and were re-inseminated on D22. There was no difference (p > 0.10) in the pregnancy rate at D20, D30 and D60 after first TAI between the control (69%, 59.7% and 57%, respectively) and P4-LA (67%, 55.7%, and 55.2%, respectively) groups. Pregnancy losses were similar between both groups (p > 0.1). For cows submitted to the second TAI, the pre-ovulatory follicle size did not differ (p > 0.1), but the oestrous detection and pregnancy rates were greater (p < 0.05) in the P4-LA group (92.2% {[}59/64] and 60.9% {[}39/64], respectively) than in controls (75% {[}42/56] and 44.6% {[}25/56]). The cumulative pregnancy rate after two TAIs did not differ (p > 0.1) between control (73.3% {[}135/184]) and P4-LA (76% {[}146/192]) groups. The use of P4-LA at 12 days after TAI potentially increases the pregnancy rates for a new early resynchronization strategy associated with the Doppler imaging for pregnancy diagnosis and results in an alternative to perform two TAIs in 22 days in beef cows. (AU)

• Processo FAPESP: 15/10606-9 - Inovações no diagnóstico precoce da gestação em bovinos
• Beneficiário: Guilherme Pugliesi
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 16/23964-3 - Inovações no diagnóstico precoce da gestação em bovinos
• Beneficiário: Guilherme Pugliesi
• Modalidade de apoio: Bolsas no Brasil - Jovens Pesquisadores
• Processo FAPESP: 17/26767-7 - Eficácia do diagnóstico de gestação pela Ultrassonografia Doppler aos 20 dias pós-IATF em vacas Nelore ressincronizadas com ou sem progesterona injetável
• Beneficiário: Danilo Zago Bisinotto
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica