A dual approach is required to diagnose the cause or causes of the production of herd milk of inferior compositional quality. By studying the results of the analysis of a milk sample in conjunction with accurate information obtained at the farm, it is frequently possible to trace the origin of the problem and, hence, give reliable advice to overcome it. Simple flow diagrams are available as an aid to the Adviser and the diagrams for milk fat, protein and lactose are illustrated.

Case histories are available to illustrate the approach used and indicate the effects of advice on milk production and compositional quality. When diagnosis is difficult, a more detailed investigation is necessary. This might involve the sampling and analysis of foods and the analysis of samples of milk from individual cows. The use of automated infra red spectrophotometric instruments for milk analysis and the processing of results using computers, enable large numbers of samples to be dealt with expeditiously and at low cost.