Bluetongue in cattle is hard to spot and costly, and the animals don’t always develop immunity, warns dairy farmer Frederic Coens (pictured).
Spotting the symptoms of bluetongue disease is far from easy in dairy cattle, but the economic costs are considerable.
“The first sign we had this year was when yields started to drop in August,” said Frederic Coens, who milks 70 Holstein dairy cows at Oedelem near Bruges in west Belgium. Soon after, the animals’ noses started to swell and their movements slowed down.
But the real impact came in late October, when eight of the cows lost their calves at eight-and-a-half months pregnant. “It seems that the risk is greatest during the dry period.”
As well as the loss of calves, milk yield for the whole herd is about 15% down this year, while vet bills and extra feed costs are also eating into profit.
Mr Coens is particularly aggrieved that he bought 56,000 litres of milk quota for €84,000 (£60,000) last year and this is now not needed. He is milking three times a day at the moment to try to catch up.
Eight of the heifers also lost their calves, at about five months pregnant. These have been served again and will have their first calves at three years old, affecting milk yields.
To combat bluetongue, Mr Coens says it is essential to bring the cows in at night during the summer. His herd has been housed full-time since early September. He has also used pour-on insecticides three times and increased the energy in the diet. Providing mineral supplements in the dry period can also help with cow health.
But Mr Coens does not believe that cows develop natural immunity, since one of his milkers has been hit by bluetongue two years in a row.