Erratum

Unfortunately, after publication of this article [1], it was noticed that the axis numbering of Fig. 4 was switched. The numbering of the x-axis should be on the y-axis and vice versa. The corrected figure can be seen below.

Fig. 4
figure 1

Drug localization in horse hair as a function of the time of documented drug administrations. This graph shows the median distance from skin and range of segments with clearly increased drug incorporation. The slop of the resulting linear relationship is consistent with an average growth rate of 1.84 cm per month