There is provided an exemplary method of treating weaning piglets to induce weight gain, or to prevent a reduction in rate of weight gain, the method comprising exposing the weaning piglets to a rabbit maternal pheromone having an interomone effect. In an exemplary embodiment, the rabbit maternal pheromone is trans-2-methyl-2-butenal. The method may include the step of applying the rabbit maternal pheromone to a feeder for the weaning piglets. Moreover, the rabbit maternal pheromone may be applied to a feeder (or to the feed) for the weaning piglets at least once during a first week of weaning. Further, the method may include weighing the weaning piglets at intervals to determine a rate of weight gain, and measuring an amount of feed consumed by the weaning piglets to calculate the amount of weight gained per unit of feed consumed.
