Hot, dry weather has farmers in northern Ontario buzzing with concern over insects that are bugging their livestock.

The north's warmer summers and milder winters have encouraged new types of insects to move further north in recent years.

Ron Bonnett, president of the Canadian Association of Agriculture, said farmers' livestock have been particularly tormented by the horn fly, which sucks blood from young cattle.

Bonnett, who raises beef cows in Bruce Mines, said it's extremely stressful for the animals.

"You can have everything from severe weight loss to, on occasion … young calves that were so tormented that they actually have died because of the stress," he said.

Bonnett said he lost a calf three weeks ago after it was weakened by flies and then attacked by ravens.

Not eating and drinking enough

Over in the northwest, biting flies are also bothering cows.

Gary Sliworsky, a Ministry of Agriculture advisor in the Rainy River district, said the drier weather seems to be drawing more of the nipping nuisances.

He said the cows will "bunch up in groups trying to protect themselves from the flies and they don't go out and eat and drink like they should. It's a co-operative protection from the bugs."

But if the cows don’t eat properly, farmers could lose money because beef cattle are sold by weight.

He said the dry weather has also reduced hay crops — and that could affect how much food is available for cattle over the winter.