| Full text | |
| Author(s): |
Ayres, H.
[1, 2]
;
Ferreira, R. M.
[1, 2]
;
Cunha, A. P.
[2]
;
Araujo, R. R.
[1, 2]
;
Wiltbank, M. C.
[2]
Total Authors: 5
|
| Affiliation: | [1] Univ Sao Paulo, Dept Anim Reprod, Sao Paulo - Brazil
[2] Univ Wisconsin, Dept Dairy Sci, Madison, WI 53706 - USA
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | Theriogenology; v. 79, n. 1, p. 159-164, JAN 1 2013. |
| Web of Science Citations: | 35 |
| Abstract | |
Previous studies reported increased fertility using Ovsynch for presynchronization before Ovsynch (Double-Ovsynch), as compared with presynchronization with two prostaglandin F-2 alpha (PGF(2 alpha)) treatments before Ovsynch (Presynch-Ovsynch). This study compared ovarian follicular dynamics and hormone concentrations during Double-Ovsynch versus Presynch-Ovsynch. Lactating Holstein cows (N = 193) were assigned to one of two treatment groups: (1) Presynch (N = 93), two injections of PGF(2 alpha) 14 days apart, followed by the Ovsynch-timed Al protocol 12 days later; and (2) Double-Ovsynch (N = 100), one injection of GnRH, PGF(2 alpha) 7 days later, and GnRH 3 days later, followed by the Ovsynch-timed Al protocol 7 days later. All cows received the same Ovsynch-timed Al protocol: GnRH (G1) at 68 +/- 3 days in milk (mean +/- SEM), PGF(2 alpha) 7 days later, and GnRH (G2) 56 hours after PGF(2 alpha). Ultrasonographic evaluations of the ovaries and blood sampling were performed at G1, PGF(2 alpha), G2, and 6 days after the G2 injection of the Ovsynch-timed Al protocol. Double-Ovsynch decreased the percentage of cows with low circulating progesterone (P4) concentrations (<0.50 ng/mL) at G1 (12.0% vs. 30.1%; P = 0.003) and increased the percentage of cows with medium P4 concentrations (0.50 > P4 <= 3.0 ng/mL) at G1 (80.0% vs. 57.0%; P < 0.01), and with CL at G1 (94.0% vs. 67.8%; P < 0.01). Double-Ovsynch also increased the percentage of cows with high P4 (>3.0 ng/mL) at PCF2 alpha (88.0% vs. 76.3%; P = 0.04) and tended to increase average circulating P4 at PGF(2 alpha) (3.52 +/- 0.17 ng/mL vs. 3.09 +/- 0.21 ng/mL; P = 0.11). Double-Ovsynch also tended to increase percentage of cows ovulating to G1 (80.0% vs. 69.9%; P = 0.11) and G2 (98.0% vs. 93.5%; P = 0.08). Thus, presynchronization of cows with Double-Ovsynch induced ovulation in noncycling cows and appeared to increase most aspects of synchronization during the Ovsynch protocol. (C) 2013 Elsevier Inc. All rights reserved. (AU) | |