Population Medicine, University of Guelph, Guelph, Ontario, CanadaN1G 2W1.
Animal. 2020 Mar;14(S1):s44-s54. doi: 10.1017/S1751731119003227.
Aspects of neutrophil function are diminished or dysregulated in dairy cows in the weeks just before and after calving, which appears to be an important contributor to the occurrence of retained placenta, mastitis, metritis and endometritis. The timing and mechanisms by which specific elements of neutrophil function are impaired are only partially understood. Oxidative burst capacity is the element of neutrophil function most consistently shown to be impaired in the week after calving, but that observation may partially be biased because oxidative burst has been studied more than other functions. There is sufficient evidence to conclude that the availability of calcium and glucose, and exposure to elevated concentrations of non-esterified fatty acids or β-hydroxybutyrate affect some aspects of neutrophil function. However, these factors have mostly been studied in isolation and their effects are not consistent. Social stressors such as a competitive environment for feeding or lying space should plausibly impair innate immune function, but when studied under controlled conditions such effects have generally not been produced. Similarly, treatment with recombinant bovine granulocyte colony-stimulating factor consistently produces large increases in circulating neutrophil count with modest improvements in function, but this does not consistently reduce the incidence of clinical diseases thought to be importantly attributable to impaired innate immunity. Research is now needed that considers the interactions among known and putative risk factors for impaired neutrophil function in dairy cows in the transition period.
奶牛在分娩前后数周内，其中性粒细胞功能的某些方面会减弱或失调，这似乎是导致胎衣不下、乳腺炎、子宫炎和子宫内膜炎发生的一个重要因素。中性粒细胞功能特定元素受损的时间和机制仅部分被理解。氧化爆发能力是中性粒细胞功能中最一致地显示在分娩后一周内受损的元素，但这一观察结果可能部分存在偏差，因为氧化爆发比其他功能受到了更多的研究。有充分的证据可以得出结论，钙和葡萄糖的供应以及暴露于升高的非酯化脂肪酸或β-羟丁酸浓度会影响中性粒细胞功能的某些方面。然而，这些因素大多是单独研究的，它们的影响并不一致。社会应激因素，如竞争的采食或躺卧空间，可能会削弱先天免疫功能，但在受控条件下进行研究时，通常不会产生这种影响。同样，用重组牛粒细胞集落刺激因子治疗会一致地增加循环中性粒细胞计数，适度改善功能，但这并不总能降低被认为与先天免疫受损有关的临床疾病的发生率。现在需要研究在过渡期奶牛中，已知和推测的影响中性粒细胞功能的因素之间的相互作用。
