The invention relates to a method for the non-therapeutic treatment of pigs for the purpose of reducing the conversion ratio of the feed used to raise the pigs and/or for increasing the growth rate of the pigs. The treatment comprises orally administering at least one glycine compound to the pigs, which glycine compound corresponds to the following formula (I) or to a salt or an ester thereof: wherein R1 and R2 are independently an alkyl, an alkenyl or a hydroxyalkyl radical containing 1 to 18, preferably 1 to 6 carbon atoms or wherein R1 and R2 form jointly together with the N atom a heterocyclic 5- or 6-membered ring. The glycine compound is preferably N,N-dimethylglycine (DMG).
