Importance of Fly Control to Lessen Your Chance of Pinkeye in Your Herd

While we’re all excited for the warm weather and sunshine, pinkeye, Moraxella bovis, can bring
quite a headache this time of year.
Eye irritation, cloudy cornea, excessive tearing are all signs of pinkeye, which can cause
permanent blindness in cattle.
Pinkeye causes reduced weaning weights, economic loss and takes time to treat. After all costs
are accounted for, it could be costing you well over $100 per head. 1 The economic cost alone
should make pinkeye prevention top of mind, but the stress it brings to cattle should be
another reason.
If you’re weaning this time of year, pinkeye can add more stress to calves. Pinkeye can reduce
weaning weight by as much as 17-65 pounds per animal. 2 Attempting to keep stressors low
during an already stressful time, is crucial to keep calves growing.
You’re probably asking yourself… how can I better prevent pinkeye from even happening?
The biggest cause of pinkeye is face flies. 12-14 flies per face decreases grazing time by one
hour per day. 3 The reason face flies can be difficult to control is because they don’t spend very
much time on cattle, they are constantly moving from animal to animal.
If you’re using tags, proper timing is crucial. If you administer fly tags while you bring up cattle
for spring branding and vaccinating, fly tags are often administered 60 days prior to fly season,
therefore compromising the efficacy. 2 To get the most bang for your buck, you may need to
bring cattle up solely to tag them.
Insect Growth Regulators are a great choice because the cattle don’t have to be handled in
order to achieve the fly control. Cattlemen can put IGRs in feed, mineral or salt, and the animals
simply ingest the larvicide. It passes through the animal and starts to work in the cattle manure
where flies lay their eggs.

1  Bovine Veterinarian, Pinkeye Prevention Preferred, (Feb. 23,
2  Beef Magazine, How To Prevent & Treat Pinkeye In Cattle,
(Apr. 01, 2010).
3  University of WI-Madison Livestock Division of Extension, Managing and Preventing Pinkeye,