Real Clear Science has a strange Japanese experiment (published in PloS ONE) in which researchers stole an insect-repelling trick from zebras and gave black cattle white stripes – to make them happier and more productive by shooing off biting flies:
The irritating insects cause cows to graze less, eat less, sleep less, and also to bunch together into tightly clumped groups, which stresses the animals and leads to more injuries. The damage done by biting flies equates to roughly $2.2 billion in yearly economic losses for the U.S. cattle industry.
And so, the researchers painted six Japanese Black cows with black-and-white stripes, which took just five minutes per cow. They then observed the cows for three days, taking high-resolution images of them at regular intervals to count the insects on the animals and also recording any fly-repelling behaviors like leg stamping, tail flicking, and skin twitching. The same cows were also observed for three days with painted-on black stripes (to see if it was the paint chemicals, not the coloring, that repelled flies) and and with no stripes at all.
The apparent effects of the stripes were remarkable. The number of biting flies observed on zebra-striped cows was less than half the number seen on unpainted cows and far less than cows painted with black stripes. Moreover, zebra-striping reduced fly-repelling behaviors by about 20%, indicating that the cows were less bothered by the insects.
The cattle industry commonly sprays pesticides to combat biting flies, but the researchers say that painting stripes with non-toxic materials could be cheaper, healthier for livestock, and better for the environment.
You can see the original study here. There are pictures, too.