Use and limitations of profiles in assessing health or nutritional status of dairy herds.

A number of factors limit the usefulness of blood or metabolic profiles. These include sampling problems, low correlations with nutrient intake, inconsistent patterns in disease, and difficulties in interpretation. Despite these limitations, profiles properly used may serve as an adjunct to more conventional technology in alleviating some dairy herd problems. Their use appears justified when feed analysis, ration evaluation, disease testing, and checks on management do not alleviate herd problems. Considerable potential for misuse of profiles exists due to the complexities of interpretation.