College of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, Western Australia 6150, Australia; Faculty of Veterinary and Agricultural Sciences, University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia; Animal Welfare Science Centre, University of Melbourne, Victoria 3010, Australia.
CSIRO Agriculture, Armidale, New South Wales 2350, Australia.
J Dairy Sci. 2019 Apr;102(4):3282-3294. doi: 10.3168/jds.2018-14578. Epub 2019 Feb 7.
The objectives of this study were to assess antibody and cellular immune responses in first-lactation dairy heifers reared under a pasture-based production system and to investigate associations between immune competence and stress responsiveness, health, and productivity. A commercial vaccine was used to induce antibody and cellular immune responses and, based on measured responses, animals were classified as above average, average, and below average for each trait independently and in combination (overall immune competence). Overall immune competence phenotypic rankings were generated by combining standardized residual values for antibody and cellular responses measured in individual heifers. Cortisol responses to handling and yarding were used to assess stress responsiveness, worm egg counts were used to assess internal parasite burden, somatic cell counts to assess udder health and estimates of total daily milk volume, and milk fat and milk protein contents to assess productivity. A total of 393 Holstein-Friesian and Holstein-Friesian × Jersey crossbred heifers from 2 herds practicing seasonal calving in a pasture-fed production system were enrolled in the study. The immune competence phenotypes of individual heifers were assessed before their first mating and their subsequent performance during their first lactation was monitored. Animals with below-average antibody and cellular immune competence had higher serum cortisol concentrations compared with their counterparts following handling, suggesting they had a reduced ability to cope with management-induced stress. Furthermore, a significant negative (favorable) correlation was observed between antibody responses and stress responsiveness. Similarly, correlations between antibody responses and internal parasite burden were significant and negative (favorable). No correlations were observed between overall immune competence and milk yield, milk fat, and milk protein content.
本研究旨在评估在牧场生产系统中饲养的首胎奶牛的抗体和细胞免疫反应，并研究免疫能力与应激反应、健康和生产性能之间的关系。使用商业疫苗来诱导抗体和细胞免疫反应，并根据测量的反应，将动物分别归类为每个特征的高于平均水平、平均水平和低于平均水平，以及综合（整体免疫能力）。通过对个体奶牛的抗体和细胞反应的测量值进行标准化残差的组合，生成整体免疫能力表型排名。处理和围场时的皮质醇反应用于评估应激反应，蠕虫卵计数用于评估内部寄生虫负担，体细胞计数用于评估乳房健康和总日奶量的估计值，以及乳脂和乳蛋白含量用于评估生产性能。共有 393 头荷斯坦-弗里森和荷斯坦-弗里森×泽西杂交奶牛来自 2 个在牧场饲养生产系统中实行季节性产犊的牛群，参与了这项研究。在它们第一次交配前评估了个体奶牛的免疫能力表型，然后监测它们在第一次泌乳期间的后续表现。与其他处理后的奶牛相比，抗体和细胞免疫能力低于平均水平的动物在处理后血清皮质醇浓度更高，这表明它们应对管理引起的应激的能力降低。此外，抗体反应与应激反应之间存在显著的负相关（有利）。同样，抗体反应与内部寄生虫负担之间的相关性也是显著的，且为负相关（有利）。整体免疫能力与产奶量、乳脂和乳蛋白含量之间没有相关性。
