Kittens and cupcakes in the Rayburn building caused a buzz Thursday among staffers and interns, but the reason for their presence was anything but a cute ball of fluff.

For the past 50 years, the Department of Agriculture has been forcing 100 kittens each year to eat toxoplasma-infected raw meat to test their stool, according to Michigan Republican Rep. Mike Bishop.

The parasite causes toxoplasmosis and is found only in cat feces, putting the brunt of these experiments on kittens. They are needed to breed the parasite, which is then studied, according to a report by watchdog group the White Coat Waste Project. Researchers later kill the kittens because they are deemed unfit for adoption given the potential health hazards they could cause owners, according to a USDA Agricultural Research Service spokesperson.

The spokesperson called the estimation of 100 cats per year used in experiments a “serious over-estimation” and said the cats are essential to this sort of research.

The White Coat Waste Project first uncovered documentation of the experiments in May through a Freedom of Information Act request. Since then, 100,000 constituents have sent letters to lawmakers demanding action, according to Bishop.