Transit tetany is a disease associated with transport stress. It is caused by hypocalcaemia, sometimes complicated by hypomagnesaemia. It is often associated with periods of food and water deprivation while being transported or held in yards, and may be precipitated by rough handling. The disease can occur in any animal, but those at greater risk are older, fatter, pregnant or lactating animals. The grazing of lush pasture, heavy feeding with grain or pellets prior to transport, and forced exercise immediately after transport also increase risk.
Clinical Signs and Diagnosis
Initially there is restlessness, incoordination and sometimes aggression. Knuckling of the hind legs and staggering may develop with the animal falling, becoming laterally recumbent, frothing at the mouth and grinding teeth. Without treatment affected animals may become comatose and die.
Diagnosis is made from history of transport and clinical signs. No specific lesions are present on necropsy.
Laboratory confirmation requires a serum sample submitted chilled for measurement of calcium and magnesium concentrations.
Differential diagnoses include exhaustion, polioencephalomalacia and lead poisoning – in the latter two diseases, animals appear blind.
Administer subcutaneous injections of commercially available solutions containing both calcium borogluconate and magnesium sulphate, and rub in well to hasten absorption into the bloodstream. Slow intravenous administration may be required in severely affected animals, but this should be done under veterinary guidance to avoid risk of cardiac arrest if administered too quickly or in large amounts. As soon as possible, sit the animal upright if in lateral recumbency, to avoid inhalation of any regurgitated rumen contents.
Feed cattle with adequate roughage and avoid prolonged feed curfews before transporting long distances. Avoid working cattle after long periods of transport until adequate rest, feed and water have been provided. Reduce periods of feed and water deprivation, especially in the above mentioned higher risk groups. Implement low stress handling methods.