Cure of Experimental Canine Blacktongue with Optimal and Minimal Doses of Nicotinic Acid

Twenty-six dogs were studied in thirty-five attacks of acute blacktongue in their response to treatment with nicotinic acid at various dose levels under standardized conditions. The minimum effective daily dose of nicotinic acid as judged by growth response, storage, prompt return of appetite and disappearance of the classical mouth symptoms was 0.5 mg. per kilogram. Daily doses of 1.0, 1.5 and 10 mg. per kilogram of body weight were equally effective. When the dose was reduced to 0.2 mg. per kilogram daily, the curative response was delayed. The weight remained constant or decreased during the first 5 to 8 days of treatment while the mouth lesions healed, then there was a gradual moderate gain in weight with return of appetite. A dose of 0.1 mg. per kilogram daily was completely ineffective in restoring the appetite and in preventing the loss of weight, but was sufficient to arrest the progress of and partially heal the mouth lesions, at the same time decreasing the rate of the weight loss. A solution of nicotinic acid autoclaved for 6 hours was just as effective even at the lower levels of 0.2 mg. and 0.5 mg. as was the unautoclaved material.