6 September 2002

Grass-gorged cows have calving difficulties

TOO much grass in dry cow paddocks may be the reason behind an increase in calving difficulties over recent weeks, according to independent vet consultant Tony Andrews.

"Vets are calving more cows than usual at this time of year and there are probably many more cows experiencing calving problems which they do not see."

The increase in difficult calvings could be due to exceptional grass growth, says Dr Andrews. "Cows have had too much grass for too long and become too fat. Excess fat around the birth canal makes it harder for the calf to pass through."

Delayed calving dates, due to difficulties with inseminating at the usual time during the foot-and-mouth crisis, may also be a factor contributing to over-fat cows, he adds.

Cows should calve at condition score 2.5 which means keeping them on bare paddocks during the dry period, he says. "Even when the paddock looks like a billiard table, grass could still be growing quickly. To check whether cows are stocked heavily enough, offer straw or silage. When they refuse it, they are too lightly stocked."

High grass intakes can also increase the risk of cows succumbing to milk fever at calving, says Dr Andrews. "On farms where management is good, milk fever levels should be no more than 5%. Cows which have had milk fever yield less and are more likely to suffer mastitis.

"Where milk fever incidence is high, discuss control strategies with a vet," he advises &#42

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