Novel cephalosporins of the formula ##STR1## in which R.sup.1 is an aliphatic or cycloaliphatic hydrocarbyl radical of up to 6 carbon atoms which is optionally substituted by a carboxyl group, ##STR2## R.sup.2 and R.sup.3 each independently is an optionally substituted aliphatic or cycloaliphatic hydrocarbyl radical of up to 6 carbon atoms, but is not unsubstituted methyl,or pharmaceutically acceptable salts thereof, are effective antibacterially and promote the growth of animals.