The relationship between lice infestation in calves during their first winter and damage to the leather produced was investigated in a trial involving 500 calves, 100 of which were treated with a pour-on endectocide during the first winter. All the calves received routine lice treatment in the second winter and were reared to slaughter weight. The hides were removed at the abattoir, tanned, inspected for lice-related damage, and graded according to their suitability for the production of high quality leather. The untreated group developed natural infestations of the chewing louse (Bovicola bovis) during the first winter but none was observed in the second winter. Hides from cattle infested with lice in their first winter had higher levels of lice damage than hides from those treated with eprinomectin, at both the chrome-tanned and dried dyed-crust stages of leather production.