Back from the Vet: Milk Fever in Goats
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Winter is here, and does are done breeding. Now is the time of patient waiting for spring and bouncing kids. While planning for your kidding season, it is important to ensure your does are not at risk for any pregnancy-associated disease. Among those diseases is hypocalcemia, low blood calcium. Goats, in particular, are at risk for hypocalcemia or milk fever. Dairy cows tend to manifest this disease after birth and at peak lactation, while sheep tend to manifest this condition in the last few weeks of pregnancy. Unfortunately, goats can suffer from this disease at any of these times.
Goats affected by hypocalcemia or milk fever can exhibit a variety of clinical signs. Less severe disease can produce only lethargy and inappetence. More severe disease, particularly in goats, can be indicated by muscle spasms, twitching, and a stiff gait. Affected goats can also be hyper-excitable with abnormal staggering movements. As the disease progresses, goats become unable to rise, and if untreated, quickly die.
Hypocalcemia occurs due to increased demands on the goat’s body for calcium, particularly due to late-term pregnancy or lactation. As fetuses mature and their bones mineralize, they require increasing amounts of calcium. This occurs particularly in the last one to three weeks of pregnancy. As goats frequently have multiple kids, they require even further calcium. Increased demand for calcium is also present in the first several weeks of lactation and at peak lactation, especially in high-producing dairy goat breeds. Goats are required to mobilize stored calcium during these events, as well as increase calcium absorption, to meet increasing demands. Lack of appropriate calcium intake, especially during these times, puts goats at significantly increased risk of this condition.
Treatment of milk fever involves the careful intravenous infusion of calcium gluconate followed by increased oral intake or oral supplementation of calcium. Affected does show a rapid improvement immediately following intravenous calcium supplementation. However, if calcium is given too rapidly or given to animals with normal calcium levels, it can result in death.
Feeding appropriate dietary calcium is the key to the prevention of milk fever in goats. Particularly during times of increased calcium demand, goats should be offered forages such as alfalfa that are rich in calcium. Grains do not have significant amounts of calcium. Maintaining a proper ratio of calcium to phosphorus is also necessary. The ratio should be greater than 1.5:1, calcium to phosphorus. Increased grain feeding may be helpful in meeting the energy requirements associated with late-term pregnancy, but it will increase phosphorus and provide minimal calcium, putting does at increased risk of hypocalcemia.
Careful management of pregnant and lactating does will greatly reduce the risk of milk fever. If maintaining animals on pasture, it is advisable to supplement with a small amount of high-calcium feed, such as alfalfa, particularly if the pasture is poor through winter. Assessing does via ultrasound for the number of fetuses can allow for increased feeding of does with multiple fetuses. When animals are primarily in a shelter, especially in heavy winter areas, it is also imperative to ensure adequate sunshine exposure or vitamin D, to allow for optimum dietary calcium absorption. It is also advised to avoid induction of stress, such as hoof trimming or transport, during late-term pregnancy and early lactation. These events can cause does to go off of feed and may result in hypocalcemia due to lack of intake.
Management of hypocalcemia in dairy cows has been heavily studied. Many animals are now fed a special diet to induce a state of metabolic acidosis and reduce hypocalcemia incidence. Unfortunately, the exact mechanism of hypocalcemia in goats is not understood as it is in cattle. Thus, it is not recommended to use this method in goats. Ensuring that goats have enough dietary calcium, but not too much, is the best advice.
Unfortunately, milk fever is not the only condition that can occur in goats during late pregnancy. Pregnancy toxemia, or metabolic ketosis, occurs when does cannot meet the energy demands of late-term pregnancy. Does suffering from this condition, similar to hypocalcemia, can show lethargy and lack of food intake. A definitive diagnosis of hypocalcemia rather than pregnancy toxemia can be made by measuring the blood calcium level. A tentative diagnosis can be made by assessing response to intravenous calcium treatment when testing is unavailable. Pregnant animals showing signs of possible milk fever should also be assessed for pregnancy toxemia, and vice-versa. Other conditions, such as polioencephalomalacia or listeriosis, can also appear similar to hypocalcemia.
Hypocalcemia can cause serious illness in pregnant and lactating does. Establishing a nutrition plan for your does through pregnancy and lactation will reduce the risk of any animals contracting milk fever. Speaking with your extension agent or herd veterinarian can help you to ensure you are meeting all of your herd’s nutritional needs. Early identification and treatment of the disease can ensure does make a full recovery. If you are concerned that does in your herd may be experiencing milk fever, contact your herd veterinarian. Treatment for hypocalcemia in an animal with normal calcium can be harmful rather than helpful.
Menzies, Paul. June, 2015. Merck Veterinary Manual: Parturient Paresis in Sheep and Goats. https://www.merckvetmanual.com/metabolic-disorders/disorders-of-calcium-metabolism/parturient-paresis-in-sheep-and-goats
Van Saun, Robert. Common Nutritional and Metabolic Diseases of goats. http://goatdocs.ansci.cornell.edu/Resources/GoatArticles/GoatFeeding/GoatNutritionalDiseases1.pdf
Originally published in the January/February 2021 issue of Goat Journal and regularly vetted for accuracy.