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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.)

Equine chorionic gonadotropin increases fertility of grazing dairy cows that receive fixed-time artificial insemination in the early but not later postpartum period

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Author(s):
Prata, Alexandre B. ; Pontes, Guilherme C. S. ; Monteiro, Jr., Pedro Leopoldo J. ; Drum, Jessica N. ; Wiltbank, Milo C. ; Sartori, Roberto
Total Authors: 6
Document type: Journal article
Source: Theriogenology; v. 98, p. 36-40, AUG 2017.
Web of Science Citations: 4
Abstract

This study evaluated effects of equine chorionic gonadotropin (eCG) on fertility of 679 crossbred (Bos taurus x Bos indicus) lactating grazing cows synchronized for fixed-time AI (FTAI). At a random day of the estrous cycle cows received an intravaginal progesterone (P4) implant, 2 mg estradiol benzoate (EB) and 100 mu g gonadorelin (DO-AM). On D7-AM, cows received 0.5 mg sodium cloprostenol and were randomly assigned into two treatments: eCG (n = 340; 400 IU eCG on D7), or Control (n = 339; no eCG). On D8-PM, P4 implants were removed and cows received 0.5 mg sodium cloprostenol and 1 mg EB. Insemination was performed on D10-AM. Pregnancy was diagnosed 30 and 60 d after AI. Treatment with eCG tended to increase pregnancy per AI (P/AI) compared to Control at 30 (37.8 vs. 30.2%; P = 0.06) and 60 (31.9 vs. 25.1%; P = 0.08) d. Pregnancy loss and twinning did not differ between groups. Treatment with eCG increased (P < 0.05) P/AI at 30 (39.0 vs. 25.2%) and 60 (32.8 vs. 21.3%) d for cows inseminated at <= 70 d in milk (DIM) but had no effect in cows receiving AI after 70 DIM. Thus, eCG on D7 of a FTAI protocol increased fertility of crossbred dairy cows inseminated in the early postpartum period. (C) 2017 Elsevier Inc. All rights reserved. (AU)

FAPESP's process: 13/26956-3 - Physiological, endocrine and molecular responses to protocols for artificial insemination stimulated with chorionic gonadotropins
Grantee:Alexandre Barbieri Prata
Support type: Scholarships in Brazil - Doctorate