EN
On the basis of skin scrapings collected together with cerumen from the inside of ears, the occurrence of a hidden mite and louse infection was assessed to evaluate its effect on the productive traits of gilts fattened during 1996-1997 at Pig Testing Stations (PTS). The productivity was highly intluenced by the station factors. The low level of infection had, however, some negative effect in a few cases, and in few it was not elear, probably due to the phenomenon of resilience.