{
    "abstract": "The study aimed to evaluate the effects of GnRH given 34\u2009h after progesterone (P4) intravaginal device (IVD) removal in a timed artificial insemination (TAI) protocol. In Experiment 1, 17 Hereford and Braford heifers (control, n\u2009=\u20097; GnRH34; n\u2009=\u200910) received 2\u2009mg estradiol benzoate (EB) and a 1 g P4 IVD on Day 0 (D0). On D8, IVDs were removed and 150\u2009\u03bcg d-cloprostenol (PGF) and 1\u2009mg estradiol cypionate (EC) were administered. In the GnRH34 group, animals received 25\u2009\u03bcg lecirelin 34\u2009h after the IVD removal (D9). TAI was performed in both groups on D10 (48\u2009h after IVD removal). Follicular dynamics were evaluated from D8 until ovulation; blood samples were collected 7 and 12\u2009days after TAI. In Experiment 2, to evaluate the effect of GnRH34 on pregnancy rates (control, n\u2009=\u2009187; GnRH34; n\u2009=\u2009203), heifers were subjected to the TAI protocols described in Experiment 1. No significant differences were observed in preovulatory follicle (POF) diameter on D10, follicular growth and ovulation rates until 72\u2009h and P4 concentrations on days 7 and 12 after TAI (p\u2009>\u20090.05). Pregnancy rates (PR) were similar between groups (Control\u2009=\u200950.2%; GnRH34\u2009=\u200950.2%; p\u2009=\u20090.65). A significant effect of body weight (BW) and body condition score (BCS) on PR was observed for control (p<\u20090.05), but not for GnRH34. In conclusion, GnRH 34\u2009h after the IVD removal in beef heifers previously treated with EC had no effect on luteal function and fertility.",
    "authors": [
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.\nFaculdade de Veterin\u00e1ria, FiBRA, Universidade Federal de Pelotas, Cap\u00e3o do Le\u00e3o, RS, Brazil.",
            "firstname": "Julia Nobre Blank",
            "initials": "JNB",
            "lastname": "Camozzato"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.",
            "firstname": "Bruna Favretto de",
            "initials": "BF",
            "lastname": "Souza"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.",
            "firstname": "Jo\u00e3o Marcello",
            "initials": "JM",
            "lastname": "Rodrigues"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, FiBRA, Universidade Federal de Pelotas, Cap\u00e3o do Le\u00e3o, RS, Brazil.",
            "firstname": "Alinne Machado Petrarca",
            "initials": "AMP",
            "lastname": "L\u00e9o"
        },
        {
            "affiliation": "Empresa Brasileira de Pesquisa Agropecu\u00e1ria (EMBRAPA), Porto Velho, RO, Brazil.",
            "firstname": "Luiz Francisco Machado",
            "initials": "LFM",
            "lastname": "Pfeifer"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.",
            "firstname": "Marcelo",
            "initials": "M",
            "lastname": "Bertolini"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.",
            "firstname": "Monique Tomazele",
            "initials": "MT",
            "lastname": "Rovani"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, FiBRA, Universidade Federal de Pelotas, Cap\u00e3o do Le\u00e3o, RS, Brazil.",
            "firstname": "Rafael Gianella",
            "initials": "RG",
            "lastname": "Mondadori"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, FiBRA, Universidade Federal de Pelotas, Cap\u00e3o do Le\u00e3o, RS, Brazil.",
            "firstname": "Bernardo Garziera",
            "initials": "BG",
            "lastname": "Gasperin"
        },
        {
            "affiliation": "Faculdade de Veterin\u00e1ria, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.\nFaculdade de Veterin\u00e1ria, FiBRA, Universidade Federal de Pelotas, Cap\u00e3o do Le\u00e3o, RS, Brazil.",
            "firstname": "Fernando Caetano de",
            "initials": "FC",
            "lastname": "Oliveira"
        }
    ],
    "conclusions": null,
    "copyrights": "\u00a9 2025 Wiley\u2010VCH GmbH. Published by John Wiley & Sons Ltd.",
    "doi": "10.1111/rda.70025",
    "journal": "Reproduction in domestic animals = Zuchthygiene",
    "keywords": [
        "beef cattle",
        "fertility",
        "ovulation",
        "pregnancy",
        "timed artificial insemination"
    ],
    "methods": null,
    "publication_date": "2025-03-03",
    "pubmed_id": "40028831",
    "results": null,
    "title": "Luteal Function and Pregnancy Rate in Bos taurus Heifers Treated With GnRH Prior to Timed Artificial Insemination.",
    "xml": "<Element 'PubmedArticle' at 0x788503870220>"
}