A practice that is decried by animal rights activists and many scientific experts, and was recently made illegal in California, remains popular among American dairy farmers.
According to a 2002 report from the U.S. Department of Agriculture, just over half of America's dairy farmers dock the tails of some or all of their cattle, though a more recent study from Colorado State University suggests that more than 80 percent of U.S. dairy farms may practice docking. Docking involves either cutting off much of the tail of a young animal or using a rubber ring to stop blood circulation to the end of the tail of an older animal so it will fall off or can be easily cut off.
The video to the left shows the process of tail docking. WARNING: GRAPHIC CONTENT.
Farmers who practice docking say docking prevents disease and contributes to the cleanliness of cow udders, since undocked tails are more likely to collect fecal matter from the cow's rectum.
Lyndon Odell of Willet Dairy, one of New York state's largest dairies, says docking helps keep cow barns clean generally. "If you have a cow that's lying in an area in the barn and she's got her tail swapping around she's going to get up swinging it around," said Odell, "and the material is going to be thrown around."
Supporters of docking also believe it protects cows from mastitis, an inflammation of the cows' udders, and shields dairy workers from leptospirosis, a bacterial fever that sometimes occurs among livestock workers.
Opponents claim the practice simply makes it easier for dairy workers and veterinarians to work with cows, and is not only painful for the animals, but leaves them unable to swat away flies. Said Jennifer Fearing, California director of the Humane Society of the United States, "Science has shown repeatedly that this practice is barbaric and totally unnecessary. It causes serious issues for the animals not just in the practice of losing their tail but spending the rest of their life defenseless against fly strike, which plagues many cows on farms."
Fly strike is another term for maggot infestation, or myiasis. "Flies are ubiquitous," said Fearing, "and without their tails, [cows] have no way to swat them."
A number of scientific studies in recent years have cast doubt on the belief that docking reduces mastitis. The procedure is opposed by veterinary trade groups in both the U.S. and Canada.
Many Northern European countries and some Australian states have outlawed docking. America's biggest dairy producing state, California, followed suit in 2009, becoming the first state in the nation to ban docking.
"We needed to send a zero tolerance message that ultimately every animal should be treated humanely," state Senator Dean Florez, who introduced the bill, told ABC News.
Though he ultimately signed the bill, Gov. Arnold Schwarzenegger questioned the state legislature's priorities when the bill was being considered. "Right now in the midst of a budget crisis, they are debating about cow tails," he said. "[A]sk the legislators, stop debating cow tails and let's do the budget."
A similar bill was sent to the agriculture committee of the New York state assembly last week. It would make docking a misdemeanor punishable by up to a year in prison or a $500 fine.