A St. Louis jury handed Abbott Laboratories a win Thursday, deciding that Abbott, another company and a hospital were not liable after a boy consumed the companies’ cow’s milk-based products for premature infants and became severely ill. The decision marked the first victory for north suburban-based Abbott Laboratories and Indiana-based Mead Johnson Nutrition in their ongoing battle over allegations that their cow’s milk-based formulas for premature babies cause a serious intestinal disease, and that they should warn parents of possible risks.