Effect consumption of treatment two antibiotic (Trimethoprim and Sulfamethoxazole) on heart rate and QT wave length in Holstein cows

Trimethoprim (Tr) in combination with Sulfa methoxazole (SMZ) has a wide spectrum of activity against gram positive and negative bacteria. However these drugs are usually used, numerous side effects of these drugs are reported,which consist of skin problems, blood problems, digestive, renaly and cardiovascular disease. It seems these drugs exert their side effects via potassium channel blocking and also QT interval prolongation. The aim of the current study is to study the effects of contemporaneous injection Tr and SMZ on electrocardiographic criteria in Holstein cows. To this end, 10 clinically healthy Holstein cows (5 non pregnant female and 5 male, 5 years old,about 450±25 kg) were randomly selected; then all of them were issued on electrocardiographic changes in two stages: before and after the intramuscular injection (in the neck) of Tr and SMZ (1ml of each per 10 kg body weight, twice a day for 5 successive days).and in the end cows were transferred in a calm and non-stressed place in order to take electrocardiography. A significant difference was detected in QT interval prolongation and heart rate by the drug administration Trimethoprim and Sulfa methoxazole (P