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Hypocalcemia and Eclampsia in Cattle and Dogs
by Fred Lanting
Copyright November, 2008 -
Hypocalcemia is defined as an insufficient level of calcium in the blood. Eclampsia, once also called puerperal tetany, is one of the results — in fact, the most important one. In cattle, eclampsia has been known in some areas as “grass staggers” but it occurs in non-grass-eating animals such as dogs and cats, also. Homeostasis (optimal balance) of calcium is mainly regulated by parathyroid hormone, calcitonin, and vitamin D. In dairy cows, short-term hypocalcemia usually occurs near parturition when mammary gland secretions more than double the cow’s requirements for calcium. This calcium must come from metabolized food or the animal’s own bone, or both, but such transfer is not always fast enough, and the cow “goes down”. The dairyman must be right there to administer a shot of calcium gluconate (the most soluble and safe calcium salt), or the cow could die. It also happens in dairy goats, but far less often.
Eclampsia (sometimes erroneously called "milk fever") is an acute and life-threatening emergency condition seen in animals shortly before or shortly after birthing their offspring — a calf or a litter, for instance. In bitches, eclampsia can be marked by one or more of these signs: nervousness as exhibited by pacing, panting, trembling/shaking, unwillingness to nurse, elevated blood pressure, edema, tetany, convulsions, seizures, paresis/paralysis, and even coma which can lead quickly to death. The very first signs of hypocalcemia (insufficient calcium circulating in the blood) that leads to eclampsia are commonly missed: excitement or other behavioral aberrations, and perhaps muscle twitching. If you are in the dog’s company you should notice the next signs, though: weakness, paresis, and perhaps convulsions and epileptic-like seizures. Certainly not all afflicted animals show all or the same signs, but others that have been reported include dilation of the dog's pupils, faster pulse rate, and elevated body temperature, all of which can be very, very serious.
It is most common in toy breeds, in (often, hyperactive) bitches with large litters. The big factor seems to be a very low ratio of dam’s body size to her litter size (and consequent milk production demand). Fortunately, most toys have only one to three pups, but the combination of a very small breed with many whelps carries a higher risk. A tiny bitch with a large and late-nursing litter requiring large amounts of calcium-rich milk is taxed concerning her ability to keep enough calcium in her own bloodstream while keeping up enough milk production for the pups. Nature often gives calcium and other-nutrients priority to whelps over the dam’s needs until it gets to the point of survival, and then instinct may cause her to kill off those hungry leeches in order to survive for hopefully better conditions in the future. Some claim that such post-partum eclampsia hysteria or instinct to survive at the expense of her whelps may be a survival manifestation.
The disease in household pets occurs most frequently in small, hyperactive dog breeds and occasionally in cats. In dogs, the greatest risk of hypocalcemia comes at peak lactation; i.e., when the demand by growing pups is greatest just before they start ingesting enough prepared food in place of or in addition to mother’s milk. This is often about 3 to 4 weeks after delivery. If your bitch is treated for hypocalcemia-with-eclampsia, it is advisable to hand-rear the whelps for at least 24 hours after treatment. An experienced breeder might be able to show you how to tube-feed. However, as I said, prevention is preferable. Normally, this is accomplished by insuring that the bitch has a good-quality, highly digestible ration especially in her third trimester (in cats, all during pregnancy). I recommend supplementation or partial replacement with eggs, cottage cheese, and meat, in order to maintain digestibility without excessive bulk that comes from grains, and to approximate the ideal calcium-phosphorus ratio of between 1:1 and 1.4:1. Almost never would calcium supplementation outside of such a partial dietary approach be healthy. It would be very rare if the dog needed a different ratio, and then only under supervision of a board-certified nutritional expert.
Although the dangers of calcium pills or powders added to a good normal diet have been explained over and over in the past 30 or 40 years, breeders who do not “read up” (keep current) on the science of breeding and nutrition often give brood bitches calcium-pill supplements during pregnancy or even all during life. This practice not only does not prevent eclampsia, it can actually contribute to its occurrence during future pregnancies. These changes decrease the ability of the dog to extract or shift calcium from its bone “storage rooms”, when more of the mineral is needed for milk. It takes 1 to 3 weeks to reverse the effects. Of course, this is not fast enough, and this is why hypocalcemia and eclampsia occur even if you recently improved the dog’s diet.
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Editor’s Note: A well-respected and frequent GSD specialty and all-breed judge for many clubs around the world, with KC and other-country credentials, Mr. Lanting since 1966 has lectured on Gait-and-Structure, Canine Orthopedic Disorders, and other topics, and has judged in about 30 countries, including the prestigious FCI Asian Shows hosted by Japan Kennel Club and the KC of India, the Scottish Kennel Club, and many National Specialties in the USA and elsewhere. He has been described by a former OFA director as the world’s leading non-veterinarian authority on hip dysplasia. A dog breeder since 1945, a GSD owner since 1947, and a show judge since 1979, he has lectured at numerous veterinary schools in the USA and abroad. He is the author of “must read” books for the dog owner (see below for ordering info). Curriculum Vitae available upon request.
Announcing the new “Canine HD and Other Orthopedics Disorders” book: The expanded revision is a comprehensive (nearly 600-page), amply illustrated, annotated, monumental work that is suitable as a coffee-table book, a reference work for breeders and veterinarians, and a study adjunct for veterinary students. It is equally valuable for the owner of any breed. It covers every aspect of HD and other orthopedic, bone, or spinal disorders, and includes genetics, diagnostic methods, treatment options, and the role of environment. Your autographed copy will be mailed from the USA as soon as the appropriate amount is received and is processed. Pricing: US $68, plus $5 postage in the U.S., or ask about mail overseas. Combine orders with “The Total German Shepherd Dog” by the same author ($50 plus postage). 17 of the 20 chapters are suitable for owners of any breed.
