Previous experiments in this series showed that a major cause of the disappointing milk yield response to the partial replacement of grass silage by urea-treated whole crop wheat (WCW) was the low digestibility of the WCW. The present experiment was designed to investigate the effectiveness of various treatments in improving milk production from such diets. Treatments examined included pre-treatment of the WCW to improve digestibility, replacing part of the concentrates by molasses or ground wheat to increase rumen ammonia utilisation, and increasing the digestible undegradable protein (DUP) content of the concentrates.