Any little nuisance, even a fly, can make a big impact on milk and meat production on your farm. Dr. Scott Pertzborn is a veterinarian specializing in dairy and beef cattle.

“Well, it’s a big deal, especially on our dairy cow where we’re you know, we’re hoping they’re making 100 pounds or more a day, and we’ve got a lot of herds that are averaging over 100 pounds, any little thing can throw the cattle off. So they deserve to have a little nuisance in their life, as we can possibly make it for them when they’re working so hard and so that nuisance it and they’re less likely to lay down. So they’re standing more, more stress on their feet, switching their tail, just general annoyance factor. And so it’s one more thing they’re doing when they could be eating.”

Flies are a main way to spread pink eye from animal to animal by carrying bacteria.

“The bacteria can be picked up on the fly to spread to the neighbor, but also it’s just a source of irritation for their eyes you’re in. Once you get them irritated, they’re much more likely to get infected. So you can do things like insecticide fly tags, so they always have that insecticide right next to their eye. I kind of like that. You can also do some pour-ons occasionally.”

In a pasture, manure isn’t shoveled away like it is in the barn, and that becomes a great breeding ground for flies.

“And it’s kind of hard to get ahead of that. I’d say, what are we going to do that manure is just sitting there, so an insect growth regulator can help make it a lot less friendly for the flies to reproduce.”

If you’ve got a problem with flies on the farm, you need to find where they’re breeding.

“So the traditional areas we think of, one is people may not think of the calf hutches. If you’ve got an organic bedding source in there, like straw, and if that calves been in there a month or so, that’s a great place for flies to breed. Also, the old bedding packs for as heifers are growing up, is a great place. Any place there’s a decaying organic matter is great for fly populations.”

Pertzborn says when it comes to tackling this issue, cleanliness is next to godliness.

“Just get rid of that stuff. Spread it out in the field. And then another thing that’s really commonly done is to feed a insect growth regulator to your young stock. Some people even feed it to the cows, but anyway, it stopped the flies from reproducing in the manure. And that can be of great benefit. And it’s probably underutilized. I think a lot of milk replacers have it in so for those calf hutches we were just talking about, and then also in minerals and so forth, and especially minerals for our cattle that are out on pasture.”