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Delchiaro SB, Oliveira PVDLF, Júnior RJP, Gonçalves GD, Morotti F, Seneda MM. Relationships between antral follicle count and reproductive characteristics of embryo-recipient mares. J Equine Vet Sci 2024; 134:105029. [PMID: 38346582 DOI: 10.1016/j.jevs.2024.105029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 01/16/2024] [Accepted: 02/06/2024] [Indexed: 02/19/2024]
Abstract
Mares (n = 77) were evaluated by antral follicle count (AFC) and selected as embryo recipients. Cyclic recipients received embryos between days 4-6 after ovulation. The acyclic recipients received an intramuscular (i.m.) protocol with 5mg of estradiol benzoate (EB) on the day of donor ovulation (D0; D-4 recipient), 3mg of EB on the following day (D1; D-3 recipient), and 3mg of EB (D2; D-2 recipient). Furthermore, 1500mg of progesterone (P4) i.m. given on D0 of the recipient (D4 donor) followed by 1500mg of P4 on the day of ET (D4-6 recipient). On the ET day, the AFC and animals' weight, body condition score (BCS), corpus luteum diameter, age and degree of uterine edema (UE) were measured. Pregnancy was confirmed on days 12 and 30. Low AFC was defined as ≤11 follicles (n = 43 mares) and high AFC as >11 follicles (n = 34 mares). Data were analyzed by a mixed effect model, including AFC group, reproductive seasonality, and season (P ≤ 0.05). UE was influenced (P = 0.05) by reproductive seasonality. The conception rate was higher (P = 0.016) in recipients with low (79.07 %) than high AFC (61.76 %) and higher (P = 0.005) in cyclic (81.40 %) than anestrus (58.82 %) mares. In addition, we observed a tendency (P = 0.06) for the interaction of AFC*reproductive seasonality, showing that high*anoestrus recipients had the lowest conception rate (37.50 %b) compared to high*cyclic (83.33 %a), low*anoestrus (77.78 %a) and low*cyclic (80 %a). The conception rate was higher in cyclic recipients with low AFC. Furthermore, UE was influenced by reproductive seasonality and mares in anestrus showed a higher degree of UE than cyclic mares.
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Affiliation(s)
- Sofia Botsaris Delchiaro
- State University of Londrina (UEL), Highway Celso Garcia Cid, PR-445, Km 380 - Campus Universitário, Londrina, PR, 86057-970, Brazil.
| | | | - Rubens José Paulossi Júnior
- State University of Londrina (UEL), Highway Celso Garcia Cid, PR-445, Km 380 - Campus Universitário, Londrina, PR, 86057-970, Brazil
| | - Gabrieli Dutra Gonçalves
- State University of Londrina (UEL), Highway Celso Garcia Cid, PR-445, Km 380 - Campus Universitário, Londrina, PR, 86057-970, Brazil
| | - Fábio Morotti
- State University of Londrina (UEL), Highway Celso Garcia Cid, PR-445, Km 380 - Campus Universitário, Londrina, PR, 86057-970, Brazil
| | - Marcelo Marcondes Seneda
- State University of Londrina (UEL), Highway Celso Garcia Cid, PR-445, Km 380 - Campus Universitário, Londrina, PR, 86057-970, Brazil.
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Canto Souza AC, Dutra Gonçalves G, Souza Ferro AO, Nakayama Yokomizo D, Vinicius Bonato D, Marcondes Seneda M. STRATEGIES TO INCREASE FERTILITY DURING FIXED-TIME ARTIFICIAL INSEMINATION IN BEEF CATTLE. SPERMOVA 2021. [DOI: 10.18548/aspe/0009.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The application of Fixed Time Artificial Insemination (FTAI) protocols has strongly boosted artificial insemination in Brazilian bovine herds. The control of the estrous cycle with protocols based on progesterone and estrogen involves synchronizing the emergence of a follicular wave, controlling the progesterone phase, and inducing ovulation in a synchronized manner. The increase in pregnancy rates starts with the preparation of the breeding season and the choice of protocols and females. Thereafter, based on the characteristics of the property and the lots of animals, small adjustments can be made to the hormonal protocols as needed. Finally, resynchronization can increase usability by allowing multiple inseminations within short periods. The search for new strategies is of paramount importance for the development of the FTAI protocol and the increase in final pregnancy rates. Thus, this review sought to highlight the main critical points and adjustments of the FTAI protocols and their applicability in the reproduction of beef cattle.
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