The invention relates to products and methods for increasing the productivity in farming by improving the fertility of healthy farming mammals. More in particular, the invention relates to products and methods for improving the fertility of animals by reducing placental insufficiency. According to the invention, this is obtained by providing a product which is enriched in L-arginine. The arginine products of the invention may be applied to improve fertility, which may be used in improving the yield in viable offspring of an animal livestock.
