Researchers at the University of Wisconsin, in coordination with a team of scientists from the Nestlé Purina PetCare Company, recently discovered the key to unraveling one of the animal kingdom’s most unappetizing bodily phenomena — hairballs.

Working with a team of Purina scientists, UW Animal Science Professor Mark Cook decided to look at the makeup of hairballs in order to come up with a solution for cats everywhere.

Hairballs, also called by the scientific term “bezoars,” are collections of hair ingested primarily during cats’ grooming rituals. The team found that fat is a major ingredient of most hairballs, making up fifteen to thirty percent of their content.

The fat, remaining undigested in the stomach from other elements in cats’ diets, traps incoming hair and binds it together. The problem plaguing many cat owners arises when cats are required to cleanse themselves of the dietary leftovers, leaving evidence of the phenomena on cat owners’ carpets and furniture whenever enough builds up to warrant its excretion.

Because the hair contained in bezoars were discovered to be coated by fat, an enzyme to break up the hair itself would prove ineffective.

Cook and the Purina team of researchers decided to try to break up, or emulsify, the fat contained in hairballs in order to let the hairballs’ elements pass through the digestive tract without restriction. Many emulsifying agents are already in existence, some commonly included in products such as dish soap and low-fat salad dressing.

“I had never even seen a hairball,” Cook said, “but I told Purina to put twenty in a box and send them to me.”

The bezoar emulsification trials, performed in test tubes in Cook’s lab, proved successful. “I don’t know why nobody ever figured it out,” Cook said. “The solution was so simple — so simple it’s incredible.”

The solution debuted in Purina Special Care Advanced Nutrition Hairball Formula cat food this summer, though a patent on the idea was issued to the Wisconsin Alumni Research Foundation and Purina over the summer of 2002. The cat food uses soy lecithin, a common food-grade fat emulsifier, to perform the duty of breaking up the stomach-clogging bezoars.

Cat foods formulated to treat the buildup of hairballs in the past have relied heavily on the use of fiber to persuade the passage of hair through the digestive tract. These solutions, however, reduced the intake of required nutrients, increased the amount of food needed for the same amount of nourishment and increased the amount of excrement created by cats, Cook said.

Applications of similar fat-emulsifying agents in humans and other animals may prove useful in treating several ailments. People who chew or eat their hair to an excessive degree and carnivorous animals that eat hairy prey may both benefit from a solution to break up collections of hair in stomachs. Hair buildup in the stomach in these situations can become hazardous and block the animals’ digestive tracts.

Cook and the Purina team are not currently collaborating on any other research projects, though they maintain a very good relationship, Cook said.