Diet quality testing is a powerful tool that can be used to guide decisions to improve the economics and effectiveness of a supplementary feeding progrm. Ben McKenzie, manager of Yaralla near Cunnamulla in south-west Queensland, implemented NIRS and phosphorus testing in his herd. The results indicated phosphorus was a primary concern for his cattle. The results also identified the relative importance of energy versus protein in the supplement given the current diet. Nutrition is a vital part of successful reproductive performance, so a targeted, effective and affordable supplementation program could have large impact on herd productivity.