Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows
We investigated the effect of an additional GnRH 2 d after initiation of resynchronization on d 25 post-AI on the proportion of cows without a corpus luteum (CL) at nonpregnancy diagnosis (NPD) and pregnancy per AI (P/AI) of cows with a CL at NPD that were reinseminated. Once per week, cows that wer...
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Elsevier
2024-11-01
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| Series: | JDS Communications |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666910224000735 |
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| author | Iago Matheus Rosa Leão Anthony Carbajal César Narciso Carlos Eduardo Cardoso Consentini Roberto Sartori João Paulo Nascimento Martins |
| author_facet | Iago Matheus Rosa Leão Anthony Carbajal César Narciso Carlos Eduardo Cardoso Consentini Roberto Sartori João Paulo Nascimento Martins |
| author_sort | Iago Matheus Rosa Leão |
| collection | DOAJ |
| description | We investigated the effect of an additional GnRH 2 d after initiation of resynchronization on d 25 post-AI on the proportion of cows without a corpus luteum (CL) at nonpregnancy diagnosis (NPD) and pregnancy per AI (P/AI) of cows with a CL at NPD that were reinseminated. Once per week, cows that were inseminated 25 d earlier were randomly assigned to receive either a GnRH treatment only (G25) or GnRH on this day and 2 d later (G25&27). Pregnancy diagnosis and CL presence were determined d 32 post-AI using ultrasonography. Nonpregnant cows with a CL were enrolled in different strategies for resynchronization of ovulation according to parity (primiparous or multiparous) and CL size. Primiparous and multiparous cows with a CL ≥20 mm in diameter continued Resynch-25 (PGF2α on d 32; PGF2α on d 33; GnRH on d 34; and AI on d 35). Multiparous cows with CL <20 mm restarted a modified Ovsynch at NPD (GnRH – 7 d – PGF2α – 1 d – PGF2α – 1 d – GnRH – 1 d – AI). Primiparous cows with CL diameter <20 mm started an Ovsynch+CIDR protocol on the day of NPD (GnRH + CIDR inserted – 7 d – PGF2α + CIDR removed – 1 d – PGF2α – 1 d – GnRH – 1 d – AI). Cows without a CL were not enrolled in any resynchronization program for a week and were excluded from fertility analyses. In multiparous cows only, the additional d 27 GnRH treatment was associated with a decreased P/AI 32 d and 102 d post-AI for the AI before treatment. The overall proportion of nonpregnant cows without CL did not differ between treatments. Yet, the GnRH treatment 27 d after AI tended to increase the proportion of overall nonpregnant cows with CL <20 mm at NPD. Treatment did not affect fertility parameters of primiparous cows with a CL ≥20 mm that continued Resynch-25 at NPD. Primiparous cows in G25&27 with CL <20 mm and submitted to Ovsynch+CIDR at NPD tended to have decreased P/AI 102 d after AI and calving/AI. When fertility parameters of primiparous cows with a CL independent of size at NPD were analyzed combined, no effect of treatment was observed. Treatment did not affect fertility of multiparous cows with CL <20 mm enrolled in Ovsynch at NPD. Multiparous cows in the G25&27 group that had a CL ≥20 mm and continued Resynch-25 at NPD tended to have a greater calving/AI due to a decreased total pregnancy loss. In summary, no treatment effect was observed on the overall fertility of primiparous cows with CL at NPD. In multiparous cows, G25&27 was associated with a decreased fertility of the previous AI, but it tended to increase calving/AI for multiparous cows with CL at NPD by decreasing the total pregnancy loss for the AI after treatment. |
| format | Article |
| id | doaj-art-b4842eee440f4b2fb322df68d5049e59 |
| institution | Kabale University |
| issn | 2666-9102 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | JDS Communications |
| spelling | doaj-art-b4842eee440f4b2fb322df68d5049e592024-11-22T07:39:17ZengElsevierJDS Communications2666-91022024-11-0156695699Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cowsIago Matheus Rosa Leão0Anthony Carbajal1César Narciso2Carlos Eduardo Cardoso Consentini3Roberto Sartori4João Paulo Nascimento Martins5Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, WI 53706Sequoia Veterinary Services, Tulare, CA 93274Sequoia Veterinary Services, Tulare, CA 93274Department of Animal Sciences, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, Brazil, 13418Department of Animal Sciences, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, Brazil, 13418Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin–Madison, Madison, WI 53706; Corresponding authorWe investigated the effect of an additional GnRH 2 d after initiation of resynchronization on d 25 post-AI on the proportion of cows without a corpus luteum (CL) at nonpregnancy diagnosis (NPD) and pregnancy per AI (P/AI) of cows with a CL at NPD that were reinseminated. Once per week, cows that were inseminated 25 d earlier were randomly assigned to receive either a GnRH treatment only (G25) or GnRH on this day and 2 d later (G25&27). Pregnancy diagnosis and CL presence were determined d 32 post-AI using ultrasonography. Nonpregnant cows with a CL were enrolled in different strategies for resynchronization of ovulation according to parity (primiparous or multiparous) and CL size. Primiparous and multiparous cows with a CL ≥20 mm in diameter continued Resynch-25 (PGF2α on d 32; PGF2α on d 33; GnRH on d 34; and AI on d 35). Multiparous cows with CL <20 mm restarted a modified Ovsynch at NPD (GnRH – 7 d – PGF2α – 1 d – PGF2α – 1 d – GnRH – 1 d – AI). Primiparous cows with CL diameter <20 mm started an Ovsynch+CIDR protocol on the day of NPD (GnRH + CIDR inserted – 7 d – PGF2α + CIDR removed – 1 d – PGF2α – 1 d – GnRH – 1 d – AI). Cows without a CL were not enrolled in any resynchronization program for a week and were excluded from fertility analyses. In multiparous cows only, the additional d 27 GnRH treatment was associated with a decreased P/AI 32 d and 102 d post-AI for the AI before treatment. The overall proportion of nonpregnant cows without CL did not differ between treatments. Yet, the GnRH treatment 27 d after AI tended to increase the proportion of overall nonpregnant cows with CL <20 mm at NPD. Treatment did not affect fertility parameters of primiparous cows with a CL ≥20 mm that continued Resynch-25 at NPD. Primiparous cows in G25&27 with CL <20 mm and submitted to Ovsynch+CIDR at NPD tended to have decreased P/AI 102 d after AI and calving/AI. When fertility parameters of primiparous cows with a CL independent of size at NPD were analyzed combined, no effect of treatment was observed. Treatment did not affect fertility of multiparous cows with CL <20 mm enrolled in Ovsynch at NPD. Multiparous cows in the G25&27 group that had a CL ≥20 mm and continued Resynch-25 at NPD tended to have a greater calving/AI due to a decreased total pregnancy loss. In summary, no treatment effect was observed on the overall fertility of primiparous cows with CL at NPD. In multiparous cows, G25&27 was associated with a decreased fertility of the previous AI, but it tended to increase calving/AI for multiparous cows with CL at NPD by decreasing the total pregnancy loss for the AI after treatment.http://www.sciencedirect.com/science/article/pii/S2666910224000735 |
| spellingShingle | Iago Matheus Rosa Leão Anthony Carbajal César Narciso Carlos Eduardo Cardoso Consentini Roberto Sartori João Paulo Nascimento Martins Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows JDS Communications |
| title | Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows |
| title_full | Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows |
| title_fullStr | Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows |
| title_full_unstemmed | Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows |
| title_short | Effect of an additional gonadotropin-releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows |
| title_sort | effect of an additional gonadotropin releasing hormone 2 days after the initiation of a resynchronization program 25 days after artificial insemination on fertility of lactating dairy cows |
| url | http://www.sciencedirect.com/science/article/pii/S2666910224000735 |
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