Investigation of the death of calves after epileptiform seizures associated with metabolic disorders

Death of calves after epileptiform seizures can be caused by metabolic disorders including hypomagnesaemia,
although a range of other conditions may also be implicated and therefore also warrant investigation.
Hypomagnesaemia is primarily observed in herds where calves are fed exclusively with either milk or milk
substitute products. Hyperparathyroidism is associated with congestion and hypertrophy of the parathyroid
gland and causes both hypercalcaemia and hypophosphataemia. However, its exact aetiology currently
remains unclear. The purpose of this study was to explain epileptiform seizures in calves from a cattle herd
presenting both deaths and decreased average daily gain (ADG). A Montbeliard herd with calves presenting
epileptiform seizures from the age of five weeks was studied. The herd consisted of 39 cows and 46 calves.
Tachycardia, nervousness and trampling, violent seizures of tetany lasting approximately 15 minutes were all
observed, while opisthotonos was observed in 5 calves. Three of the latter calves died. The remaining calves
presented a decreased ADG. Blood and urine biochemical assays were performed on 8 sick calves to determine
the aetiology of the clinical signs. The assays revealed normo/hyper-calcaemia, hypophosphataemia and
hypomagnesaemia, as well as hypocalciuria, hyperphosphaturia and hypomagnesuria. Deficiencies in iodine,
iron and vitamins A, D3 and E were also reported in the herd. These calves could potentially be suffering
from hyperparathyroidism. Hyperparathyroidism results in hypomagnesaemia, hypovitaminosis-A and, on
occassion, hypercalcaemia and hypophosphataemia. This condition can lead to seizures, muscular problems,
heart attacks and anorexia. The simultaneous occurrence of hypomagnesaemia, hyperparathyroidism and
hypovitaminosis-A has been never described in related research literature. This is, therefore, in all likelihood
a new metabolic disorder facing young cattle. Blood and urine biochemical assays are important tools for the
detection of this pathological entity in calves. A dosage of parathyroid hormone (PTH) by the enzyme-linked
immunosorbent assay (EIA) method using a kit suitable for cattle can be used to detect hyperparathyroidism.