Magnesium for Goats
-by Jaclyn De Candio Magnesium is a macronutrient essential for maintaining proper nerve and muscle function in ruminants. But supplementing magnesium for goats isn’t as simple as popping a capsule once or twice a day. For our goat herds, we want to balance the requirements in the diet and respond to deficiencies quickly.
The science of magnesium for goats.
It’s not difficult to supply magnesium for goats in the ration as most complete goat feeds are supplemented with ideal amounts. Magnesium can be found naturally in various forages and grain products, including wheat bran, linseed, and cottonseed.
Due to its wide distribution, magnesium for goats tends to be present in diets in larger amounts than other minerals. Half of this distribution is concentrated in the bone, and a portion of the remainder is in the cells of soft tissues, with the highest amounts in the liver and skeletal muscle.
If the concentration of blood magnesium becomes too low, the muscular system won’t be able to function, leading to a lack of coordination, staggers, and eventual death in a condition called grass tetany. Cool-season grasses (which grow rapidly in spring) are often the biggest culprit due to their high levels of nitrogen and potassium, which limit sufficient magnesium absorption.
Deficiencies from more than grass.
But forages aren’t the only culprits for deficiencies of magnesium for goats. Low rumen sodium, too little roughage in the diet, and low dietary phosphorus and salt can lead to magnesium deficiencies.
“Ruminant animals are unique in their predisposition to this disease process, and both feeding and agronomic management practices are needed to minimize the potential for this disease,” writes veterinarian and Penn State Extension ruminant specialist Robert Van Saun in his bulletin, Grass Tetany: A Disease of Many Challenges.
Ruminants are less efficient than monogastrics at absorbing magnesium. They absorb magnesium in the rumen through the exchange of potassium and sodium.
Normal skeletal development in growing animals depends on magnesium due to its role in oxidative phosphorylation by mitochondria and the activation of enzymes. Essentially, oxidative phosphorylation is a crucial process involved in generating adenosine triphosphate, or ATP, which is the energy an animal needs for muscle function, nerve impulse propagation, and chemical synthesis
Dangers of deficiency.
According to Van Saun, magnesium is concentrated in hard bone tissue and can’t be readily released to correct dietary deficiencies.
In the case of cool-weather grass tetany, deficiency comes swiftly and is painfully obvious. Sometimes called “staggers,” affected animals may convulse, lose balance, tremble, and move around as if suffering a neurological issue. Animals die quickly unless offered supplements via oral or intravenous treatment.
Several products are available to treat grass tetany in ruminants. Since most aren’t labeled for goats, consult your vet before adding them to your medicine cabinet. These include oral CMPK (calcium, magnesium, phosphorus, and potassium) gels and liquids. With prompt treatment, animals usually recover quickly.
The best preventative measures are a strong diet and protocols that monitor access to grazing when grasses are especially lush. You can also seed your pasture with more legumes to help avoid a flush of cool-season grass and avoid fertilizers with nitrogen.
Be wary of excess when supplementing magnesium for goats.
Toxicity isn’t as regularly reported as deficiency since grass tetany is the most prevalent issue related to magnesium. But that’s not to say toxicity won’t do damage as well.
According to the textbook Basic Animal Nutrition and Feeding: “Magnesium toxicosis in animals includes depressed feed intake, diarrhea, loss of reflexes, and cardiorespiratory depression. Severe diarrhea and reduced feed intake and growth have been observed in calves fed diets containing more than 2.3% magnesium.”
Because these can be similar to many other issues, ruling out deficiency is tricky. Be sure to include it on your list when doing a “process of elimination” to pinpoint health issues. If you’re feeding a commercial bagged feed, having a ruminant nutritionist review the feed tag and ensure sufficient mineral concentration may be helpful.
Alternatively, if you’re feeding a custom ration you either formulated yourself or got from another goat breeder, submitting a sample to a lab for analysis and verifying the nutritional profile is highly recommended. Labs can be a valuable source for answering questions about results — remember, goat diets are complicated to balance properly without professional help. Don’t hesitate to seek advice from a small ruminant nutritionist if you have any concerns.
Though magnesium is widely available and easily fed to goats, metabolic issues can develop quickly. Learn to recognize deficiency symptoms and have a plan of action in case of emergencies.
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JACLYN DE CANDIO is a professional agriculture writer, communications specialist and farmer. A member of the Ohio Farm Bureau and the Agriculture Communicators Network, she lives in southwest Ohio with her husband and children where they operate Latria Livestock Co., feeding out market kids and lambs.
SOURCES:
- Goats. (2019, August 14). Goat nutrition magnesium. https://goats.extension.org/Goat- Nutrition-Magnesium/
- Lyvers Peffer, P. A., & Day, M. L. (2014). Nutrition. In An Introduction to the Disciplines and Species of Animal Sciences (pp. 50). essay, KendallHunt Publishing Company.
- Oltenacu, E. A. B., & Stanton, T. (n.d.). Vitamins and Minerals for Goats. CALS. https://cals. cornell.edu/NYS-4-H-Animal- Science-Programs/Livestock/ Goats/Goat-Fact-Sheets/Vitamins- And-Minerals-Goats
- Pond, W. G., Church, D. C., Pond, K. R., & Schoknecht, P. A. (2005). Micro- (Trace) Mineral Elements. In Basic Animal Nutrition and Feeding (5th ed., pp. 174-176; 441). essay, John Wiley & Sons.
- Van Saun, R. J. (2021, May 25). Grass Tetany: A Disease of Many Challenges. Penn State Extension. https://extension.psu. edu/Grass-Tetany-A-Disease-Of- Many-Challenges
- https://www.ncbi.nlm.nih.gov/ books/NBK553175/
