Changes in blood composition of pregnant cows during the onset of hypomagnesaemia

Metabolic profile testing

Metabolic profiles have been used in efforts to predict periparturient problems and fertility, to diagnose metabolic disease, and to assess nutritional status. Results have been varied. Until knowledge and technology provide improved blood constituent panels, the metabolic profile should not be the first step in the diagnostic process. Rather, such profiles should follow an assessment of management practices and an evaluation of diet. However, these profiles may help to confirm the diagnosis, to convince dairy farmers that management changes are desirable, or to monitor improvement in herd animals. At this point, their major contribution has been to increase our understanding of the factors contributing to changes in blood constituent concentrations, which, in turn, has led to more efficient means of diagnosis. Except in cases of gross mismanagement, these profiles do not offer a "quick fix." In many of the reported cases in which diagnosis of herd problems was attributed to the metabolic profile, the clinician should have been able to identify the problem before the profile was conducted. Profiles are to be recommended when the cause of an existing problem is still not identified or resolved after a complete evaluation. The profile may aid in identifying a factor that has been overlooked. Profiles are not for clinicians who do not have an interest in upgrading their understanding of the factors involved, or who do not have a source of knowledgeable advice.

Hypomagnesemic tetany of ruminants

Hypomagnesemic tetany of ruminants is a noninfectious metabolic disorder that occurs in a wide range of nutritional and management conditions. This article considers its etiology and pathogenesis, clinical signs, clinical pathology and lesions, diagnosis, clinical management, prevention, and control.

Clinical pathology of bovine neurologic disease

This article describes the general and specific interpretations of common laboratory tests used to evaluate bovine neurologic disease. Cerebrospinal fluid analysis is emphasized. Comments are made about general conclusions such as hemorrhage, inflammation, infection, and neoplasia as well as specific diseases like thromboembolic meningoencephalitis. Tests in commonly available serum chemistry profiles like total calcium concentration and aspartate aminotransferase activity are described in terms of their usefulness in diseases such as parturient paresis or hepatic encephalopathy. The indications for more specific tests like ionized calcium, blood ammonia concentration, or erythrocyte transketolase are included.