Transport Tetany in Ruminants
Dr. Archana Jain, Professor & Head
Department of Veterinary Physiology and Biochemistry
College of Veterinary Science 7A. H., Mhow (MP)453446
Transport tetany also called as rail road disease or railroad sickness or staggers) mainly occurs by the development of stress due to prolonged transport of animals especially in cows and ewes in late pregnancy. it is also commonly seen in young and adult ruminants transported to feedlots and for slaughter. Even the crowded, hot, poorly ventilated vehicles which are used for transportation of these animals (railroad cars or trailers) with minimal or no access to feed or water also appear to predispose animals to the condition; however, prolonged travel by foot is also one of the important risk factor. This disease is characterized by recumbency, GI stasis, and coma, and is generally fatal.
Cows and other ruminants are most commonly affected in late gestation period. The disease is also seen in animals that have recently given birth to the young ones, as well as in bulls, steers, and dry cows. There are number of risk factors which involved in the development of this disease. These include either very heavy feeding before shipment or deprivation of feed and water for >24 hr during transit or unrestricted access to water and exercise immediately after arrival. Another most important factor is high environmental temperature. Exposure to hot environmental conditions is also associated with increased incidences of this tetany. The condition may be a form of acute hypocalcemia precipitated by late pregnancy and early lactation, or by fasting before or during transit. Physical stress is undoubtedly related. Hypomagnesemia may also one of the contributing factor in sheep and cattle.
Clinical symptoms:
Clinical symptoms in cattle may occur during transit and even after 48 hr after of arrival. Early signs include restlessness, excitement, trismus, and grinding of teeth. A staggering gait may be seen, and later, if recumbent, cattle often demonstrate paddling of the hind legs. Rumen motility becomes less and stasis of GIT is also seen. Due to this reason animals become completely off feed. Tachycardia and rapid, labored breathing may also been developed. Abortion may be there. Cattle that do not recover gradually become more obtunded to the point of coma and die within 3–4 days. Moderate hypocalcemia and hypophosphatemia may be seen in cattle. Some sheep are hypocalcemic and hypomagnesemic, but others show no measurable biochemical abnormalities. No specific lesions are found at necropsy other than lesions associated with prolonged recumbency. The most commonly seen lesions are ischemic muscle necrosis. In lambs, early signs include restlessness, staggering, and partial hind limb paralysis followed by lateral recumbency. Death can occur rapidly or after 2–3 days of recumbency. In lambs, mild hypocalcemia may be noted. Recovery rates are fair even with treatment. The relationship of clinical signs with transport or forced, prolonged exercise is diagnostic.
Treatment:
The combinations of parenteral calcium, magnesium, and glucose is very effective in these animals. I/V injections of calcium borogluconate (25% solution at 400–800 mL/cow or 100 mL/ewe) or calcium borogluconate with magnesium sulfate (5% solution, same volumes) can be administered slowly. A dose of 50 mL/day can be given SC to affected lambs in feedlots. Repeated injections may be warranted, but failure to respond is common (50%) and most likely due to concurrent muscle necrosis. Additional treatment must include I/V administration of large volumes of polyionic fluids such as lactated Ringer’s solution. Animals should be offered good quality feeds (eg, alfalfa hay), fresh water, and soft bedding with good footing underneath. Sedation may be necessary if animals are showing hyper-excitability or convulsions.
In case of unavoidable circumstances where the prolonged transport is necessary for ewes and cows in advanced pregnancy, animals should be fed a good and restricted diet for several days before shipment, then provided adequate feed, water, and rest periods during transport. In case of nervous and hyper-excitable animals it is recommended to administer some of the ataractic agents (unless transport is to slaughter) such as promazine hydrochloride before loading,. Upon unloading at the destination, animals should be allowed limited access to water for the first 24 hr and minimal exercise for 2–3 days.
https://www.pashudhanpraharee.com/transportation-of-laboratory-animals/
http://www.veterinaryhandbook.com.au/Diseases.aspx?diseasenameid=267
