Magnesium and Vitamin A Deficiency

Aaron Rutch

Magnesium Deficiency Summary

Also known as grass tetany or grass staggers, Mg deficiency is a metabolic or nutritional condition caused by low levels of magnesium in the blood. Most common in older cattle who have recently given birth but can happen to any age of ruminant livestock. Usually grass tetany occurs in early spring due to the cool-season grasses that are growing in night temperatures below 55 degrees F, grass has trouble drawing magnesium out of the soil below this temperature. This leads to a deficiency for the grazing animals, other minerals like potassium and high protein content known to be found in cooler season grasses can also lead to low levels of magnesium or imbalances. Sodium, nitrogen, Calcium, and phosphorus can effect balances as well and should be watched. Once night time temperatures rise above 55 degrees the incidence of tetany falls because grasses can draw magnesium more easily from the soil.

How To Check for Magnesium Deficiency, Prevention, Treatment

Biomass samples can be taken to check grass mineral content. Oral magnesium gel and paste tubes can be picked up and administered. Treatment can be complicated by severe nature of the animals convulsions and potentially aggressive behavior, if you think an animal is experiencing grass tetany contact your local veterinarian as soon as possible. To prevent grass tetany/Mg deficiency do not begin grazing on grasses until they have grown to 8 inches, increasing legumes on pastures like clovers can compensate for lack of grasses rich in magnesium. Applying potassium and phosphorus to spring soil will allow grasses and plants to have excess supply of minerals to grow. Pastures deficient in magnesium can be limed with dolomitic limestone. Supplementing in feed or calcium magnesium shots can also be administered.

Symptoms of Magnesium Deficiency & If Fatal

Environmental conditions and management factors combine to result in pastures with low magnesium levels. Symptoms of magnesium include grazing alone, irritability, muscle twitching, staring, in coordination, staggering, collapse, thrashing or coma. Clinical signs are not always evident before an animal is found dead.

What is Vitamin A & Roles It Plays

Vitamin A needs special attention in beef cattle and breeding cattle. Vitamin A is only found in animals, plants are the natural resource of it. Green and yellowing plants contain carotene a pigment which animals convert to vitamin A. The walls of the small intestine are the main sight where conversion of carotene to vitamin A takes place. The chief role of vitamin A is to maintain epithelial tissue which is the skin that lines the respiratory, digestive and reproductive tract. It also functions to see purple and adjust eyes to light. Vitamin A is essential for kidney function and the development of bones, teeth, and nerves.

Symptoms and Diagnostics Of Vitamin A Deficiency

Signs of vitamin A deficiency can first be detected if cattle have night blindness. If you place something in their path during twilight and they seem to stumble over it with out recognition then they have a chance of deficiency. Notices in lack of appetite, rough coat hair, dull eyes, slow gains and reduced feed efficiency. Diarrhea and pneumonia can be early signs in younger cattle. Later indicators that can occur include watery eyes, staggering gait, lameness and stiffness in hock and knees, and swelling in legs or brisket.


Vitamin A concentrates can be bought and mixed with salt to be kept dry and prevent destruction of vitamin A. Feed lot cattle can be given muscular injections that better use the vitamin and the animal can store it in their liver for up to two months. Can be purchased and supplemented in dry or liquid protein form and mixed in with feed.