Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization
We aimed to evaluate the reproductive efficiency of Nelore cows in fixed-time artificial insemination (FTAI) programs with early resynchronization. A total of 468 Nelore cows were divided into two experimental groups: R30—conventional resynchronization at 30 days (<i>n</i> = 234); R22—ea...
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MDPI AG
2025-01-01
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| author | Larissa de Paiva Nunes Gonçalves Alisson Jordão Prado Aline Pacheco Yana Eliza Feitosa de Almeida Pietro Sampaio Baruselli Welligton Conceição da Silva Antônio Humberto Hamad Minervino Jucelane Salvino de Lima Kedson Alessandri Lobo Neves |
| author_facet | Larissa de Paiva Nunes Gonçalves Alisson Jordão Prado Aline Pacheco Yana Eliza Feitosa de Almeida Pietro Sampaio Baruselli Welligton Conceição da Silva Antônio Humberto Hamad Minervino Jucelane Salvino de Lima Kedson Alessandri Lobo Neves |
| author_sort | Larissa de Paiva Nunes Gonçalves |
| collection | DOAJ |
| description | We aimed to evaluate the reproductive efficiency of Nelore cows in fixed-time artificial insemination (FTAI) programs with early resynchronization. A total of 468 Nelore cows were divided into two experimental groups: R30—conventional resynchronization at 30 days (<i>n</i> = 234); R22—early resynchronization at 22 days (<i>n</i> = 234). Both groups followed a synchronization protocol using intravaginal progesterone devices combined with the administration of steroids and gonadotropins. The R30 protocol involved resynchronization 30 days after FTAI, while the R22 protocol implemented early resynchronization 22 days after FTAI without prior pregnancy diagnosis. In both groups, one FTAI was followed by two resynchronizations. The results showed similar pregnancy rates between the groups, with the pregnancy rate in the 1st FTAI being 50.85% in the R30 group and 48.72% in the R22 group (<i>p</i> = 0.742). During the 1st resynchronization, the rates were 45.22% in the R30 group and 46.67% in the R22 group (<i>p</i> = 0.742). The cumulative pregnancy rate after the 1st FTAI, 1st, and 2nd resynchronizations was 80.77% in the R30 group and 82.91% in the R22 group (<i>p</i> = 0.643), with no significant difference observed. Follicular dynamics were also monitored, with ovulation occurring in 78.95% of cases in the 1st FTAI, 91.67% in the 1st resynchronization, and 88.98% in the 2nd resynchronization. The mean diameter of the ovulatory follicle was 13.64 ± 3.48 mm, and the largest follicle diameter was significantly greater (14.47 ± 2.76 mm) in cows that ovulated compared to those that did not (11.54 ± 4.24 mm) (<i>p</i> < 0.05), reinforcing the association between follicle size and the likelihood of ovulation. These findings indicate that both early and conventional resynchronization protocols perform similarly, with early resynchronization offering advantages in reducing the calving interval. Furthermore, the relationship between follicular diameter and ovulation confirms the importance of follicle size as an indicator of reproductive success. |
| format | Article |
| id | doaj-art-0c800a8b6a4e4ff5b776bd39effc336e |
| institution | Kabale University |
| issn | 2306-7381 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
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| series | Veterinary Sciences |
| spelling | doaj-art-0c800a8b6a4e4ff5b776bd39effc336e2025-01-24T13:52:02ZengMDPI AGVeterinary Sciences2306-73812025-01-011212710.3390/vetsci12010027Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early ResynchronizationLarissa de Paiva Nunes Gonçalves0Alisson Jordão Prado1Aline Pacheco2Yana Eliza Feitosa de Almeida3Pietro Sampaio Baruselli4Welligton Conceição da Silva5Antônio Humberto Hamad Minervino6Jucelane Salvino de Lima7Kedson Alessandri Lobo Neves8Postgraduate Program in Biosciences, Federal University of Western Pará (UFOPA), Santarem 68040-255, PA, BrazilPostgraduate Program in Animal Science, Federal University of Western Pará (UFOPA), Santarem 68040-255, PA, BrazilInstitute of Biodiversity and Forests—IBEF, Federal University of Western Pará (UFOPA), Santarem 68040-255, PA, BrazilInstitute of Biodiversity and Forests—IBEF, Federal University of Western Pará (UFOPA), Santarem 68040-255, PA, BrazilDepartment of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo 05508-000, SP, BrazilPostgraduate Program in Animal Science (PPGCAN), Institute of Veterinary Medicine, Federal University of Para (UFPA), Castanhal 68746-360, PA, BrazilLaboratory of Animal Health (LARSANA), Federal University of Western Pará (UFOPA), Rua Vera Paz, s/n, Salé, Santarem 68040-255, PA, BrazilPostgraduate Program in Animal Science, Federal University of Western Pará (UFOPA), Santarem 68040-255, PA, BrazilInstitute of Biodiversity and Forests—IBEF, Federal University of Western Pará (UFOPA), Santarem 68040-255, PA, BrazilWe aimed to evaluate the reproductive efficiency of Nelore cows in fixed-time artificial insemination (FTAI) programs with early resynchronization. A total of 468 Nelore cows were divided into two experimental groups: R30—conventional resynchronization at 30 days (<i>n</i> = 234); R22—early resynchronization at 22 days (<i>n</i> = 234). Both groups followed a synchronization protocol using intravaginal progesterone devices combined with the administration of steroids and gonadotropins. The R30 protocol involved resynchronization 30 days after FTAI, while the R22 protocol implemented early resynchronization 22 days after FTAI without prior pregnancy diagnosis. In both groups, one FTAI was followed by two resynchronizations. The results showed similar pregnancy rates between the groups, with the pregnancy rate in the 1st FTAI being 50.85% in the R30 group and 48.72% in the R22 group (<i>p</i> = 0.742). During the 1st resynchronization, the rates were 45.22% in the R30 group and 46.67% in the R22 group (<i>p</i> = 0.742). The cumulative pregnancy rate after the 1st FTAI, 1st, and 2nd resynchronizations was 80.77% in the R30 group and 82.91% in the R22 group (<i>p</i> = 0.643), with no significant difference observed. Follicular dynamics were also monitored, with ovulation occurring in 78.95% of cases in the 1st FTAI, 91.67% in the 1st resynchronization, and 88.98% in the 2nd resynchronization. The mean diameter of the ovulatory follicle was 13.64 ± 3.48 mm, and the largest follicle diameter was significantly greater (14.47 ± 2.76 mm) in cows that ovulated compared to those that did not (11.54 ± 4.24 mm) (<i>p</i> < 0.05), reinforcing the association between follicle size and the likelihood of ovulation. These findings indicate that both early and conventional resynchronization protocols perform similarly, with early resynchronization offering advantages in reducing the calving interval. Furthermore, the relationship between follicular diameter and ovulation confirms the importance of follicle size as an indicator of reproductive success.https://www.mdpi.com/2306-7381/12/1/27biotechnologybeef cattlefollicular dynamicshormonal protocol |
| spellingShingle | Larissa de Paiva Nunes Gonçalves Alisson Jordão Prado Aline Pacheco Yana Eliza Feitosa de Almeida Pietro Sampaio Baruselli Welligton Conceição da Silva Antônio Humberto Hamad Minervino Jucelane Salvino de Lima Kedson Alessandri Lobo Neves Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization Veterinary Sciences biotechnology beef cattle follicular dynamics hormonal protocol |
| title | Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization |
| title_full | Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization |
| title_fullStr | Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization |
| title_full_unstemmed | Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization |
| title_short | Reproductive Efficiency of Nelore Cows in Fixed-Time Artificial Insemination Programs with Early Resynchronization |
| title_sort | reproductive efficiency of nelore cows in fixed time artificial insemination programs with early resynchronization |
| topic | biotechnology beef cattle follicular dynamics hormonal protocol |
| url | https://www.mdpi.com/2306-7381/12/1/27 |
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