Induced cough in the early diagnosis of inflammatory respiratory diseases in calves
Cough is considered as one of the main respiratory symptoms, according to his strength, character, frequency, and duration of pain, the features of the pathological process, its localization in the respiratory organs and course of the disease can be defined. The purpose of this research is to conduct a comparative evaluation of the effectiveness of different cough induction methods for early diagnosis of airways inflammation in calves. Investigations were carried out on 60 red-motley calves of 7-14 days age. For artificial cough simulation animals were injected intravenously with 0.6% hydrogen peroxide solution of 0.9% sodium chloride solution at a dose of 0.4 ml per kg body weight, then palpation of last ring of trachea and 30-second apnea was used. Clinical observation was held continuously during 14 days, taking into account the terms of the clinical implications, severity and duration of inflammatory diseases of the respiratory system. The indicators of airways inflammation - pH and malonic dialdehyde in exhaled breath condensate were determined. It was found out that for 6-12 days prior to development of bronchitis syndrome cough in calves was caused by a 30-second apnea and H2O2-induced bronchoconstriction, but not a palpation of the last ring of trachea. Palpation of the last tracheal ring is effective only for early diagnostics of tracheobronchitis. Cough on palpation of middle and upper third of trachea defines on the later stages of tracheitis and tracheobronchitis. Determination of the sensitivity of the last trachea ring by palpation and 30-second apnea enables to conduct a differential diagnostics of early manifestations of bronchitis and tracheobronchitis in calves.