Clinical signs

Clinical signs:

Clinical signs begin two to three weeks after inoculation by the ticks. The first sign seen in a B. bigemina infection is a high fever.

Anorexia and rumen atony soon follow, although often the first observable sign is isolation of the animal from the herd. The individual will become uneasy, seek shade, and may lie down.

Infected cattle may stand with an arched back and show evidence of a roughened haircoat, dypsnea and tachycardia.

Initially the mucous membranes will be reddened and injected, followed by increased pallor as the anemia progresses. Icterus is commonly seen.

The anemia is the major factor that results in the weakness and loss of condition, as up to 75% of the erythrocytes can be destroyed over the space of a few days.

This critical presentation will pass within a week, and if the animal survives, weight loss, abortion, a drop in milk production, and a prolonged recovery time are all often seen.

Mortality rates are extremely variable and may reach levels of fifty percent or higher.

Urine will be dark red in color (hemoglobinuria), reflecting one of the initial names for the disease, "redwater."

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