That horses endure significant stress while waiting to be slaughtered has often been assumed. But a new study measuring stress hormone levels now confirms that theory, according to Italian researchers.

In the 45 minutes between removal from the holding area and stunning by captive bolt, horses' norepinephrine levels rose tenfold and epinephrine levels increased to 30 times the base rate, said Elisabetta Micera, PhD, researcher in the department of animal production in the Faculty of Veterinary Medicine at the University of Bari and lead author of the research. Plasma cortisol and beta-endorphins also increased, according to the study.

"This was the confirmation of an intuition," Micera said from her office in Italy, a country where approximately 200,000 horses are slaughtered for human consumption annually. "I could see the distress of the horses in the slaughterhouses. Horses are prey animals, and their adrenal medulla-sympathetic nervous system axes are dramatically stimulated by emotional and biological stress."

Micera's study included young male Russian draft horses that had been raised for meat production. Horses more conditioned to human handling might have different stress results, she said, but research would need to be carried out to determine those differences