Improved animal feeds and/or waters are provided, which include amendments comprising a partial calcium salt of a maleic-itaconic copolymer and a partial ammonium salt of a maleic-itaconic copolymer. The copolymers are preferably water soluble and have substantially equimolar amounts of maleic and itaconic moieties. The improved feeds and/or waters reduce volatilized ammonia derived from the decomposition of animal excrement.
