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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

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

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Author(s):
Pugliesi, G. [1] ; Santos, F. B. [1] ; Lopes, E. [1] ; Nogueira, E. [2] ; Maio, J. R. G. [3] ; Binelli, M. [1]
Total Authors: 6
Affiliation:
[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
Total Affiliations: 3
Document type: Journal article
Source: Theriogenology; v. 85, n. 7, p. 1239-1248, APR 15 2016.
Web of Science Citations: 24
Abstract

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)

FAPESP's process: 11/03226-4 - Signatures of receptivity
Grantee:Mario Binelli
Support Opportunities: Research Projects - Thematic Grants
FAPESP's process: 12/04004-8 - Effects of pre-ovulatory follicle growth on luteal function and fertility response to modulation of peri-ovulatory endocrine milieu in cattle
Grantee:Guilherme Pugliesi
Support Opportunities: Scholarships in Brazil - Post-Doctoral