BEIJING (Reuters) Chinese scientists have produced a herd of genetically modified cows that make milk that could substitute for human breast milk a possible alternative to formula in a nation rocked by tainted milk powder scandals. Researchers at the State Key Laboratory of Agrobiotechnology of the China Agricultural University introduced human genetic coding into the DNA of Holstein dairy cow embryos, and then transferred the embryos into cow surrogates. In 2003, after years of testing on mice, scientists managed to create the first cow. Over 300 cloned cattle now live on an experimental farm in suburban Beijing, with new calves delivered every week.