RESUMO
To the best of the author's knowledge, this is the first report describing the diagnostic significance of clinical as well as various biochemical variables to predict the clinical outcome of phenylbutazone [PBZ] toxicity in Egyptian draft horses. Horses with PBZ toxicity were tentatively diagnosed based on component case history and physical examination findings as well and post-mortem findings in non-survived cases. According to the clinical outcome, diseased horses were categorized into survivors [n=21] and non-survivors [n=17]. Clinically, there was a significant association between non-survivors and anorexia [p<0.01], stasis of intestinal motility [p<0.01], melena / [p<0.01], and diarrhea [p<0.001]. Biochemically, malondialdehyde [MDA/ ], nitric oxide [NO], aspartate amino transferase [AST], gamma glutamyl transferase [GGT], sorbitol dehydrogenase [SD], total bilirubin, urea and creatinine showed a significant increase [p<0.05] in non-survivors compared to survivors; meanwhile, superoxide dismutase activities [SOD], total plasma protein and albumin levels were significantly decreased [p<0.05]. To predict the clinical outcome of PBZ toxicity in examined horses, receiver operating characteristic curve [ROC] was applied for all tested biochemical variables. Analysis of ROC curve showed high sensitivity and specificity of total leucocytic count [TLC], neutrophils, band cell as well as blood urea, creatinine, total plasma protein, AST, MDA, NO, SOD and vitamin C [Vit. C] levels. It could be concluded that clinical and biochemical investigations could provide valuable diagnostic information about the adverse effects of PBZ in draft horses. Our findings also suggest that estimation of these biochemical variables might help predict the outcomes of PBZ toxicity in Egyptian draft horses