Lactose yield (kg/d) had linear and quadratic treatment effects (P = 0.05 and 0.01, respectively). The number of positive SNAP tests (>0.5 μg of AFM1/kg of milk) and total milk discarded (landfill due to regulations by the FDA on AFM1 concentrations) was greater for cows in POS than cows in CON (P < 0.0001 and P < 0.0001, respectively; POS vs. CON). The SNAP tests had a negative linear treatment effect, with the number of positive tests decreasing as the concentration of adsorbent in the diet increased (P = 0.02).