DOES PULMONARY-HYPERTENSION SYNDROME (ASCITES) OCCUR MORE FREQUENTLY IN BROILERS MEDICATED WITH MONENSIN

The performance of broilers reared in floor pens and given monensin in the feed at 121 ppm was compared with that of birds given no drug. Fe ed intake and BW gain of medicated birds was significantly lower than that of unmedicated birds from 0 to 22 d of age. Feed intake and feed conversion of medicated birds was significantly reduced, compared with unmedicated birds, from 22 to 53 and 0 to 60 d of age. Total mortalit y, and mortality due to leg abnormalities from 22 to 53 and 0 to 60 d, was significantly lower in birds given monensin. There was no differe nce in the incidence of tibial dyschondroplasia (TD) by 60 d. No diffe rences in mortality due to pulmonary hypertension syndrome (PHS) were observed for any age period. Birds removed from pens at 28 d that had received monensin had lower hematocrit and percentage saturation of he moglobin with oxygen in the blood than unmedicated birds. No differenc es in these variables were found at 54 d. There were no differences in the right ventricle weight: total ventricular weight ratios or electr ocardiogram lead II values at 28 or 54 d. The results indicate that PH S does not occur more frequently in broilers medicated with monensin.