Swat your herd's fly problem
The wet and mild winter mean fly populations are likely to be high this spring, so it’s important for dairy farmers to act early to control the pest while the majority of the population are yet to hatch.
Once temperatures rise above 10 degrees, fly eggs will start hatching, so my advice is to treat early to prevent adults laying further generations of eggs which could contribute to population explosions.
Flies can cause distress, known as fly ‘worry’, severely reducing milk yield through causing restlessness and reducing the time cows are eating. It’s estimated this reduction can be as much as 14,700 of milk per 140 cow herd over 10 weeks, which is significant, so it’s vital to act with an integrated plan to treat both the cow and the environment.
A pour-on suspension can be used which has quick initial knockdown, spreads well over the body and has some repellent activity. It’s important treatment continues throughout the season to ensure flies don’t become a problem later down the line, with some pour-ons offering eight to 10 weeks of fly control, meaning fewer applications through the season and less handling of cows, along with being more cost effective per day of treatment per animal. Speak to your vet about the best option for your herd.
It’s crucial to also identify and reduce breeding grounds by keeping the environment as clean and dry as possible, through cleaning pens and yards regularly, staggering the removal of manure piles, preventing and removing feed spillages, covering feed stores and storing hay bales off the ground.
Steph Small is a vet
