“It’s important that pathogen exposure occurs early enough in the gilt’s life so she recovers from the infection, stops shedding the pathogen and is immunocompetent at the time of farrowing” Divide the young gilt’s time before breeding into the separate categories of development and acclimation, says Dr. Clayton Johnson of Carthage Veterinary Services in the U.S.A. Development aims to prepare her physiology for a future in reproduction, acclimation tries to arm her immune system to cope with the pathogens in the sow herd. Target at least 680 grams of gain per day in the gilt developer phase. How acclimation is handled needs to be specific to each pathogen and each herd.