Figure 1
![Figure 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12917-014-0264-x/MediaObjects/12917_2014_Article_264_Fig1_HTML.jpg)
Anti-O. ostertagi antibody levels (ODR) in bulk-tank and individual milk samples during the study period. (a) Course of the anti-O. ostertagi antibody levels (ODR) during the study period in bulk-tank and individual milk samples on the 11 herds. (b) The course of the anti-O. ostertagi antibody levels (ODR) relative to the month of calving in individual milk samples of 1274 cows coming from all the 11 herds. Bars represent standard error of the mean.