by electrocardiographic (ECG)
recording. Dogs were dewormed and vaccinated against rabies,
distemper, parvovirus, hepatitis, Parainfluenza and Leptospira one
month before the start of the experiments. The study and all the
procedures were approved by the Ethical Committee of animal welfare
of the Center of Advanced Studies on Animal Health (CIESA)
of the Faculty of Veterinary Medicine, Universidad Autónoma del
Estado de México, and followed national guidelines for the production,
care and use of experimental animals specified in the
NOM-062-ZOO-1999