Improved fertility in suckled beef cows ovulating large follicles or supplemented with long-acting progesterone after timed-AI

Autor(es)

Pugliesi, G. ^[1] ; Santos, F. B. ^[1] ; Lopes, E. ^[1] ; Nogueira, E. ^[2] ; Maio, J. R. G. ^[3] ; Binelli, M. ^[1]

Afiliação do(s) autor(es)

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

^[2] EMBRAPA Pantanal CPAP, Brazilian Agr Res Corp, Corumba, Mississippi - Brazil

^[3] Ouro Fino Saude Anim, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Theriogenology; v. 85, n. 7, p. 1239-1248, APR 15 2016.
• Citações Web of Science: 24

Resumo

We aimed to evaluate the effects and the interaction of size of the preovulatory follicle (POF) and long-acting progesterone (P4) supplementation after timed-AI on CL function and pregnancy success in beef cows. In experiment 1, ovulations of beef cows were synchronized starting on Day -10, and cows were split to receive sodium cloprostenol (large follicle group; LF; n = 31) or nothing (small follicle group; SF; n = 35). Ovulations were induced on Day 0, and cows were inseminated. Ovulated cows were assigned to receive placebo (LF/control group, n = 14; and SF/control group, n = 9) or 150 mg of long-acting P4 on Day 4.5 (LF/P4 group, n = 13; and SF/P4 group, n = 12). Diameter of POF, blood flow in POF wall, ovulation rate, and size and vascularization of CL were greater (P < 0.05) in LF group. In experiments 2 (unknown cyclic status) and 4 (noncycling), ovulations were synchronized, and beef cows received placebo or 150 mg of long-acting P4 on Day 4 after timed-artificial insemination. In experiment 2, pregnancy/AI (P/AI) did not differ (P > 0.1) between P4 treated (53.2%; 209/393) and control cows (56.2%; 219/390), but P/AI was greater in cows with a CL < 0.9 cm(2) on Day 4 that were P4-treated (57.9%, 22/38) versus placebo-treated (40.4%, 21/52; P < 0.05). In Experiment 4, MI was greater (P < 0.05) in P4-treated cows (55.6%, 105/189 vs. 46.0%, 86/187). In Experiment 3, cyclic-suckled beef cows were treated as described in Experiment 1 to generate animals with small (SF; n = 111) or large POF (LF; n = 109), and subdivided to receive placebo or P4 on Day 4. POF size, ovulation rate, CL area, and P/AI were greater (P < 0.007) in the LF group. Pregnancy/AI in ovulated cows were lower (P = 0.05) in the SF/control group (41.5%, 17/41) compared to LF/control group (62%, 31/50) and were similar for the SF/P4 group (55.6%, 25/45) and LF/P4 group (57%, 28/49) compared to others. In summary, smaller and less vascularized POF results in less functional CL and reduces ovulatory rate and MI in cyclic beef cows; the long-acting P4 injection on Day 4 after timed-artificial insemination may attenuate the negative effects of small POF/CL; and postovulatory P4 supplementation improved fertility in anestrous beef cattle. (C) 2016 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 11/03226-4 - Assinaturas da receptividade
• Beneficiário: Mario Binelli
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/04004-8 - Efeitos do crescimento do folículo pré-ovulatório sobre a função luteal e do ambiente endócrino peri-ovulatório na fertilidade de fêmeas bovinas
• Beneficiário: Guilherme Pugliesi
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado