10 July 1998

Rapid grass growth brings fears of milk fever

RAPID growth is increasing the risk of milk fever in freshly calved cows, with many dry cows being offered too much grass.

Independent vet consultant Tony Andrews explains that when cows eat too much grass their metabolism is not primed to cope with the demand for calcium post- calving.

Cows may also be stressed by changeable weather increasing risks of magnesium deficiency, lowering calcium absorption, and resulting in milk fever, adds Dr Andrews.

"Dry cows are not being kept tight enough on grass, and some are getting fat. Offer cows at grass some straw, if they are not eating some straw they are eating too much grass, so grazing must be restricted.

"If you cant control grass intakes adequately it is more sensible to bring cows in two weeks before calving and control their diets." Alternatively, he advises considering injections including Vitamin D to help mobilise calcium before calving, or adjusting mineral supplement balances.