Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Prev Vet Med. 2010 Feb 1;93(2-3):147-52. doi: 10.1016/j.prevetmed.2009.10.002. Epub 2009 Nov 12.
The aim of this study was to explore whether anti-Ostertagia ostertagi antibody levels measured by ELISA in individual milk samples hold promise as a decision parameter for either herd-level decisions or selective anthelmintic treatments by investigating (1) the relationship between individual and bulk-tank milk ELISA results; (2) the relationships of individual milk ELISA results with non-parasitic cow factors and (3) the relationship between individual milk ELISA results and the milk production response after anthelmintic treatment. Twelve farms were randomly allocated to a whole-herd treatment with eprinomectin or a placebo in October 2004 and individual milk samples and a bulk-tank milk sample were collected 1 month before and 1 month after treatment. Linear mixed models were used to investigate the associations of ELISA results with (a) breed, actual milk production, lactation stage, somatic cell count, age and sampling month and (b) the milk production response after anthelmintic treatment. There was a reasonable correlation between the mean individual and bulk-tank milk ELISA results (r=0.72). Individual cow ELISA results increased with higher lactation number and were lower in November than September. The associations with the other non-parasitic factors were weak and not significant. Milk yield responses to anthelmintic treatment were greater when treatment was given in early lactation and increased with the pre-treatment ELISA result and cow age. However, these latter two interaction terms were not significant when they were put in the model together. We conclude that (1) O. ostertagi ELISA results from individual milk samples may provide more information on the herd's parasitic status than a single bulk-tank milk result; (2) lactation number should be taken into account when interpreting ELISA results from individual milk samples and (3) the value of the O. ostertagi antibody level in individual cow milk samples to predict individual production responses after anthelmintic treatment remains equivocal.
本研究旨在通过调查（1）个体奶样与奶样间 ELISA 结果之间的关系；（2）个体奶样 ELISA 结果与非寄生虫奶牛因素之间的关系；（3）个体奶样 ELISA 结果与驱虫治疗后产奶量反应之间的关系，来探讨个体奶样 ELISA 结果是否可作为牛群层面决策或有选择地进行驱虫处理的决策参数。2004 年 10 月，12 个农场被随机分配至接受伊维菌素或安慰剂的全群治疗，在治疗前 1 个月和治疗后 1 个月采集个体奶样和奶样。采用线性混合模型，调查 ELISA 结果与（a）品种、实际产奶量、泌乳阶段、体细胞计数、年龄和采样月份以及（b）驱虫治疗后的产奶量反应之间的关系。个体奶和奶样间 ELISA 结果的平均值具有良好的相关性（r=0.72）。个体牛 ELISA 结果随着泌乳次数的增加而增加，11 月份的 ELISA 结果低于 9 月份。与其他非寄生虫因素的相关性较弱，且不显著。早期泌乳时进行驱虫治疗，产奶量的反应更大，且随着治疗前 ELISA 结果和牛年龄的增加而增加。然而，当这两个交互项同时放入模型中时，它们并不显著。我们得出结论：（1）个体奶样 O.ostertagi ELISA 结果可能比单个奶样提供更多关于牛群寄生虫状况的信息；（2）解释个体奶样 ELISA 结果时应考虑泌乳次数；（3）个体奶牛奶样中 O.ostertagi 抗体水平预测驱虫治疗后个体产奶量反应的价值仍存在争议。
