Udder beauty: ensuring that dairy queens are selected for their natural splendor

Science News, July 12, 2003 by Janet Raloff

Such preening is allowed. Administering drugs, such as steroids, or giving injections is not. That's why analysis of urine has become routine at big fairs.

But only some forms of tampering are evident in urine samples. Injections of gas into the udder, for example, aren't.

Until 2000, cheats frequently injected into the udders of perfectly healthy show cows an antibiotic drug for mastitis, a condition in which milk ducts become inflamed. The antibiotic's delivery system relies on a propellant--isobutane, the fuel in cigarette lighters--that can subtly alter an udder's contours.

One spritz and a quadrant of the udder that might have been a tad small, somewhat misshapen, or asymmetrical, can be cosmetically corrected. Urine tests don't reveal that drug.

O'Brien's studies have now shown that even radiological clues to such primping with compressed gas are gone within 72 hours. But in an ultrasound scan conducted immediately following the ribbon ceremony, the doctoring showed up as distinctive black streaks penetrating from just below the skin down to bubble-shaped patterns deep within the tissue (http://www.sciencenews.org/20030712/ bob8.asp#vetsees). O'Brien found that in the first years of experimental udder scans--before judges began booting crooks from the showring--the incidence of injected gas was between 30 and 40 percent among the top-judged cows.

No sooner did he publish analyses showing how to diagnose this tampering than did the incidence of such knavery drop to a mere 5 percent--at least in shows that had advertised the Wisconsin team would be screening winners. In fact, O'Brien observes, "we hadn't seen a single case since 2000--until this April, when we stumbled on a lone instance" Some people performing the scans "didn't even recognize [the telltale pattern]," he says, "because it had been so long since we'd seen it"

Which reinforces, he says, the need for vigilance.

The current rarity of gas injections doesn't mean cheating has ended. Scoundrels have embraced a newer trick: injection of so-called mild silver protein. This liquid concoction--a purported remedy for infections that is widely available over the Internet--triggers a localized inflammation that induces swelling. By targeting the size of injections, their number, and their placement, a cow's owner can subtly reshape an udder.

O'Brien and his radiology colleagues have had their eye on this development. In tests, they injected the silver formulation at 17 sites in a half-dozen lactating cows, imaged each animal's udder with ultrasound, and then asked an outside expert to pinpoint signs of the treatment on sonograms. In the Aug. 1, 2002 Journal of the American Veterinary Medical Association, O'Brien's group reported that every injection site had been found, with no false positives. The irritant caused an unusual "corrugated appearance," the researchers note, that showed up on the ultrasound images as alternating white and black bands (see URL above).

In a subsequent test, O'Brien established that this diagnostic pattern generally persists for nearly 5 days but can last up to 16.