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Beef Management Tips
Livestock Update, October 2006
John B. Hall, Extension Animal Scientist, Beef, Virginia Tech.
Spring Calving Herds
Fall Calving Herds
Plentiful rainfall (in many areas) and cool growing conditions made excellent pasture this fall. However, the same conditions that create this lush pasture also reduce magnesium levels in pastures. In addition, well fertilized pasture can exacerbate the problem. Producers with fall-calving herds should feed a high magnesium mineral free choice this fall. Cows in early lactation are most susceptible to grass tetany.
High magnesium mineral supplements should contain 12 to 14% magnesium. The most common form of magnesium is magnesium oxide (MgO). While MgO is an acceptable form of magnesium for supplementation, it is bitter and causes cattle to decrease mineral intake. Producers should monitor mineral intake by cattle to ensure they are eating the recommended level indicated on the feed tag.
Cattle will often head for woods and wooded lots around the farm in search of grazing or browse. However, that could be dangerous. Green acorns are plentiful this year. Hungry cattle love acorns that can quickly poison them. Green and ripe acorns contain gallotannins, which cause kidney damage and death. There does not seem to be as great a problem after a few hard freezes. The reduced palatability of acorns after weathering may be part of the answer.
To prevent acorn poisoning, cattle should be allowed access to abundant pasture and fenced out of areas with large amounts of oak trees until this winter. There are few other options as only a few pounds of acorns can cause enough damage to kill cattle. Outward signs of acorn poisoning are few but include weight loss and diarrhea, but often these are not noticed until other cattle in the herd have died.