<p>A milking machine milk line nipple assembly having a flexible resilient sleeve member with transverse corrugations formed therein secured to the milk line nipple at its inner end in telescoping encasing relation and having a rigid ring member at its outer end mounted in sliding relation to the nipple and being longitudinally compressible or collapsible relative to the nipple to permit ready attachment of the milking machine connector to the nipple and automatically return to contamination protective encasing relation to the nipple upon withdrawal of the milking machine connector.</p>
