Okano Denise S, Penitente-Filho Jurandy M, Gomez León Victor E, Maitan Paula P, Silveira Camila O, Waddington Bruna, Díaz-Miranda Edgar A, da Costa Eduardo P, Guimarães Simone E F, Guimarães José D
Department of Veterinary, Universidade Federal de Viçosa, Viçosa, Brazil.
Department of Animal Science, Universidade Federal de Viçosa, Viçosa, Brazil.
Reprod Domest Anim. 2019 Mar;54(3):604-612. doi: 10.1111/rda.13401. Epub 2019 Feb 5.
This study aimed to assess characteristics of bovine cryopreserved sperm and evaluate its relation to field fertility in fixed-time artificial insemination (FTAI). Semen samples of 16 bulls were used to inseminate 811 Nellore cows, and four of these bulls were also used to inseminate 101 Nellore heifers. Samples of the same ejaculate used for FTAI from each bull were analysed in the laboratory after thawing. Sperm motility and vigour were subjectively assessed by light microscope, and integrity of the plasma and acrosome membranes, and H O production were evaluated by flow cytometer. Relation among sperm characteristics and pregnancy rate of cows and heifers were evaluated by univariate and multivariate logistic regression. Subjective sperm motility and vigour did not affect the probability of pregnancy in cows or heifers. In univariate analysis for pregnancy in cows, sperm traits related to acrosome injury positively affected probability of pregnancy mainly when associated with plasma membrane integrity; H O production seems to be less important than plasma membrane integrity in affecting probability of pregnancy. In multivariate analysis, sperm traits related to injured acrosome positively affected probability of cow and heifer pregnancies while intact acrosome was negatively related to cow pregnancy. Intact plasma membrane and high H O production were positively related to cow pregnancy but negatively related to heifer pregnancy. Results suggest that a capacitation-like status of the acrosome may benefit probability of pregnancy in cows.
本研究旨在评估牛冷冻精液的特性，并评估其与定时人工授精（FTAI）中田间繁殖力的关系。使用16头公牛的精液样本对811头内洛尔母牛进行授精，其中4头公牛也用于对101头内洛尔小母牛进行授精。在解冻后，对每头用于FTAI的同一射精样本在实验室进行分析。通过光学显微镜主观评估精子活力和活率，通过流式细胞仪评估质膜和顶体膜的完整性以及H₂O₂的产生。通过单变量和多变量逻辑回归评估精子特性与母牛和小母牛妊娠率之间的关系。主观精子活力和活率不影响母牛或小母牛的妊娠概率。在母牛妊娠的单变量分析中，与顶体损伤相关的精子特征主要在与质膜完整性相关时对妊娠概率有积极影响；在影响妊娠概率方面，H₂O₂的产生似乎不如质膜完整性重要。在多变量分析中，与顶体受损相关的精子特征对母牛和小母牛妊娠概率有积极影响，而完整的顶体与母牛妊娠呈负相关。完整的质膜和高H₂O₂产生与母牛妊娠呈正相关，但与小母牛妊娠呈负相关。结果表明，顶体的类获能状态可能有利于母牛的妊娠概率。
