The results of a linear mixed model to estimate the effect of closantel treatment at dry-off (or approximately 42 days before calving for heifers) on 305-day milk production in 11 herds exposed to <i>F. hepatica</i> (based on 402 cows).

a<p>Somatic cell count.</p

Number of cows, average ± standard deviation of anti-<i>F. hepatica</i> antibody levels before treatment and 305-day milk production in the lactation before treatment and distribution of breed, parity and year quarter of treatment in the 2 treatment groups.

<p>Number of cows, average ± standard deviation of anti-<i>F. hepatica</i> antibody levels before treatment and 305-day milk production in the lactation before treatment and distribution of breed, parity and year quarter of treatment in the 2 treatment groups.</p

The course of anti-<i>F. hepatica</i> antibody levels (ODR) during the study period in bulk-tank milk samples from the 12 studied herds (A) and relative to the months after experimental treatment in individual milk samples of 475 cows in the 12 herds (B).

<p>Bars represent standard error of the mean.</p

The average lactation curve of cows following treatment with closantel or a placebo at dry-off (Curves represent the data for Holstein Friesian cows in ≥3^rd lactation).

<p>The average lactation curve of cows following treatment with closantel or a placebo at dry-off (Curves represent the data for Holstein Friesian cows in ≥3^rd lactation).</p

The estimated effect of closantel treatment at dry-off (or approximately 42 days before calving for heifers) on 305-day milk production according to several potential decision parameters for selective anthelmintic treatment.

<p>Error bars represent the 95%-confidence interval of the treatment-effect. Categories for <i>F. hepatica</i> ELISA results and body condition score represent quartiles.</p