The present invention is related to the field of breeding domestic livestock, in particular to animal nutrition for domestic livestock, more in particular to nutritional supplements and additives for breeding monogastric mammals, most specifically inorganic nitrate compounds for use in a method of improving the (re)productive performance of a female monogastric mammal. The present invention provides, among others, a method of improving the (re)productive performance of a female monogastric mammal, feed supplements and feed compositions comprising inorganic nitrate compounds.