Bova Mag Minerals

Reduce grass tetany problems in your herd

  • Provides high levels of available magnesium
  • Reduces breeding and cleaning problems
  • Builds a healthy immune system
  • A free-choice mineral designed to help cattle that are at risk for grass tetany
  • Contains the highest bioavailability sources of magnesium
    • Many products formulated to provide supplemental magnesium for the prevention of tetany use domlomitic limestone. This is an extremely poor source of both calcium and magnesium. Furst-McNess uses only the highest bioavailable sources of magnesium in our Bova Mag products.
      Bioavailability of Magnesium Sources*
      Magnesium Oxide 100%
      Limestone (Dolomitic) 28%
  • Bova Mag Breeder 5 also includes Zinpro Availa® 4, which provides organic trace minerals that have been shown to:
    • Help cows prepare for and recover from pregnancy, calving and lactation
    • Improve immune systems in calves
    • Lower calving interval for cows
    • Improve response to vaccines
    • Reduce morbidity
    • Prime calf for better performance in feedyard
  • 50 pound bag

  • Begin providing these products at least 2 to 4 weeks prior to turning cattle to pasture.
  • This product is formulated to be consumed at 2 to 2.7 ounces per head, per day to provide approximately 9.9 grams of highly-available supplemental magnesium per day.
  • Provide one mineral feeder per 15 to 20 head of animals.
  • Location of feeders is very important. If mineral consumption is too low, placing mineral feeders closer to the heavily-traveled areas may improve consumption.
  • Do not feed to sheep or other copper-sensitive species.


What Is Grass Tetany?
Hypomagnesaemia (grass tetany) is a common metabolic disorder in beef cattle caused by low magnesium (Mg) levels in blood. Tetany refers to a medical condition characterized by continuous spasm of skeletal muscle. Cows affected by grass tetany will show signs progressing from irritability, stumbling and thrashing, to coma and death. Grass tetany can effect any type or age of cattle during any season; but older cows in early lactation, grazing lush forage in the spring are most at risk. It is also common on finishing cattle and those raised in dry lots.

What Causes Grass Tetany?
Milk production is a constant drain on magnesium levels and cows need a daily intake of Mg to maintain adequate levels in the blood. In addition, older cows cannot readily mobilize Mg from bone stores, making them more dependent on daily nutritional intake.

Since cows have a daily requirement for Mg during early lactation, cows that go off feed can show evidence of grass tetany even though they are not grazing lush grass. Grass tetany can also be seen in finishing cattle, especially if finishing diets are marginal in Mg levels. Once an animal goes off feed they do not have any reserve Mg capacity and need daily supplementation.

How Can Tetany Be Avoided? Mature, lactating beef cows are most at risk for grass tetany. If turn out can be delayed until grass is at least six inches tall, the risk for grass tetany is greatly reduced. New grass growth in cool spring weather tends to have lower Mg levels, but incorporating legumes in the pasture will increase the Mg content of the forage in the spring diet.

Since cows cannot readily mobilize body stores of Mg to maintain healthy blood levels, they need daily Mg supplements, especially those feeding on lush growing grass. Dry lot or finishing rations should also be evaluated.

Cattle at lower risk for grass tetany (stocker calves or dry cows) should be placed on high-risk pastures. In the short term, prevention of grass tetany can be accomplished by supplementing Mg in the diet.

Feeding high magnesium minerals before placing cattle under conditions favorable for grass tetany can greatly reduce the chances of tetany occurring. Feeding between 1 0 and 12 grams per head daily of highly-available magnesium the month before tetany is likely to occur can help prevent the problem from happening.

Resource: Iowa State University