12 July 2002

High calcium in grass means milk fever worry

LUSH grass continues to cause problems for a number of milk producers, with high incidences of milk fever being reported in many parts of the country.

High calcium lush grass, which has reduced fibre content, is resulting in many producers reporting higher than usual occurrence of milk fever, says independent vet consultant Tony Andrews.

While Glos-based vet James Husband does not believe that incidence is any higher this summer than most, he does suggest that some herd managers may not be treating the problem in the best manner.

"Producers tend to leave cows at grass and hope they wont be affected. But the best way to avoid milk fever is to move in-calf cows inside for the last three weeks of pregnancy to gain control of their diet and restrict calcium intake. With grazing cows it is best to offer a buffer feed, such as maize or whole-crop silage, supplemented with magnesium chloride," says Mr Husband.

It is also possible that it could be caused by an imbalance in the calcium to phosphorus ratio in forage. When calcium levels are greatly above those of phosphorus it will result in increased calcium absorption, leading to milk fever, says Dr Andrews. &#42