The objectives of this experiment were to determine clinical and clinicopathological changes after proximal duodenal obstruction in sheep. Experiments were carried out on seven Iranian crossbred male sheep aged between 2-2.5 years old and weighing 45-50 kg. All operative procedures were performed under general anesthesia by intravenous infusion of sodium thiopental. A polyethylene tube reinforced with braided cotton tape was surgically placed around the duodenum in 5 to 6 cm caudal to the pylorus. Experimental observations commenced two days before tightening the ligatures and inducing obstruction. Measurements at this stage were considered as the control values. Clinical (appetite, urination, defecation, ruminal contractions, temperature, respiratory and heart rates) and clinicopathological indices (hematological parameters, concentrations of sodium, chloride, potassium, calcium, magnesium, inorganic phosphorous, urea nitrogen, creatinine and acid-base status in serum and urine) were determined simultaneously at 12 hrs intervals for 72 hrs. At the end of the experiment the animals became lethargic, anorexic, weak and dehydrated. Finally, six sheep died and one sheep was slaughtered. There were significant differences (P<0.05) between temperature, respiratory and heart rates of the control and experimental values. Moreover, significant increases (P<0.05) in hematocrit, RBC and WBC counts, hypokalemia (P<0.05), hypochloremia (P<0.05) and metabolic alkalosis were seen in experimental sheep. Significant increases (P<0.05) were detectable in serum concentrations of inorganic phosphorous, urea nitrogen and creatinine. There were significant declines (P<0.05) in urinary concentrations of sodium, potassium, chloride, magnesium, inorganic phosphorous, urea nitrogen and creatinine as well as a significant decrease (P<0.05) in urinary pH. In conclusion, proximal duodenal obstruction in sheep leads to clinical and clinicopathological changes which are important for diagnosis.

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