Influência do diâmetro folicular e do hormônio antimulleriano (AMH) na taxa de concepção e produção leiteria de fêmeas da raça Girolando inseminadas

• Autor(a) principal: FRAGA JUNIOR, Antonio Matos
• Data de Publicação: 2020
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/8809
• topic: Girolando; Fertilidade; Hormônio antimulleriano; Produção de leite; Inseminação artificial; CIENCIAS AGRARIAS::MEDICINA VETERINARIA

One of the main biotechnologies to improve reproductive rates generating greater economic return for cattle production is artificial insemination, but these indexes are still low, mainly caused by problems in the detection of estrous, late puberty, and postpartum anestrus that affect directly reproductive performance. The size of the ovulatory follicle at the time of insemination among other factors influences the conception rate and reproductive efficiency in fixed-time Artificial Insemination (FTAI) programs. The anti-Müllerian hormone (AMH) is a component of the β transforming growth factor family (TGF-β), known for its attributions in sexual differentiation in males and females, secreted by granulosa and cumulus cells, for exerting impacts on the follicular sensitivity to FSH hormone and initial recruitment of follicles. They regulate the efficiency of follicular selection and recruitment. The objective of this work was to evaluate whether there is a relationship between AMH concentrations with the conception rate in Girolando cows inseminated FTAI in blocks. A total of 327 Girolando cows (Bos taurus indicus x Bos taurus taurus) was used in the experiment. The females were submitted to the following synchronization protocols: for primiparous and multiparous females, the protocol began in D0 with the application of intravaginal progesterone device (CIDR®, 1.9 g, Zoetis) and intramuscular application (IM) 2 mg estradiol benzoate (Gonadiol®, 2 mL, Zoetis); in the D7, application (IM) of 25 mg dinoprost (Lutalyse® 5 mL, Zoetis); D9: application (IM) of 12.5 mg dinoprost (Lutalyse®, 2.5 mL, Zoetis) and 1 mg estradiol cypionate (E.C.P® 0.5 mL Zoetis). For nulliparous cows, changes in the previous protocol were in the Application D7 (IM) of only 12.5 mg dinoprost (Lutalyse®, 2.5mL) and D9 (IM): Application of 12.5 mg dinoprost (Lutalyse®, 2.5 mL) and 0.6 mg of estradiol cypionate (E.C.P® 0.3 mL). After eleven days from the beginning of the protocol (D11), the animals were randomly divided into two groups. Control Group (n:150) and Block Group (n:179). Ultrasound evaluations were initiated an hour earlier from conventional FTAI. After ultrasound evaluation, animals of the Block Group were divided into 4 blocks according to the size of the dominant follicle. Blood collections were performed on the D11 of the protocol, by the coccygeal vein, with heparinized vacuntainer tube. After collection, blood was centrifuged (900 x G for 15 minutes) for plasma removal, which was stored in freezer at -80º C until the analyses were performed. Serum AMH concentrations (ng/mL) were analyzed using bovine anti-Mullerian hormone (Webster, TX). The data were submitted to ANOVA, when significant effect was observed, tukey's test was performed at 5% significance for this, the statistical program RBio was used. The pregnancy rate of the Block Group (70.99%) was 28.71% higher than the Control Group (42.28%). The AMH assay has a measurable analytical interval of 20 ng/mL-0.312 ng/mL. Intraassay coefficients were <= 8% and interassay was <= 12%. As conclusion, AMH concentration cannot be used as a marker for fertility determination in Girolando cows. Further studies will be necessary to use AMH as a molecular marker for milk production.