The effect of hypercapnia on the arrhythmogenic dose of epinephrine (ADE) was investigated in 14 horses. Anesthesia was induced with guaifenesin and thiamylal sodium and was maintained at an end-tidal halothane concentration between 0.86 and 0.92%. Base-apex ECG, cardiac output, and facial artery blood pressure were measured and recorded. The ADE was determined at normocapnia (arterial partial pressure of carbon dioxide [Pa(CO2)] = 35 to 45 mm of Hg), at hypercapnia (Pa(CO2) = 70 to 80 mm of Hg), and after return to normocapnia. Epinephrine was infused at arithmetically spaced increasing rates (initial rate = 0.25 micrograms/kg of body weight/min) for a maximum of 10 minutes. The ADE was defined as the lowest epinephrine infusion rate, to the nearest 0.25 micrograms/kg/min, at which 4 premature ventricular complexes occurred in a 15-second period. The ADE (mean +/- SD) during hypercapnia (1.04 +/- 0.23 micrograms/kg/min) was significantly (P < 0.05) less than the ADE at normocapnia (1.35 +/- 0.38 micrograms/kg/min), whereas the ADE after return to normocapnia (1.17 +/- 0.22 micrograms/kg/min) was not significantly different from those during normocapnia or hypercapnia. Baseline systolic and diastolic arterial pressures and cardiac output decreased after return to normocapnia. Significant differences were not found in arterial partial pressure of O2 (Pa(O2)) or in base excess during the experiment. Two horses developed ventricular fibrillation and died during normocapnic determinations of ADE. Hypercapnia was associated with an increased risk of developing ventricular arrhythmias in horses anesthetized with guaifenesin, thiamylal sodium, and halothane.

In the conditions of the Republic of Belarus there was determined the therapeutic efficacy of combined application of a complex antibacterial veterinary drug (containing lincomycin and spectinomycin) and Trivitim for the treatment of calves with respiratory diseases. In course of the study of 12 1-1,5 month old calves with respiratory diseases there were analyzed the hematological blood indexes, white blood cell differential and content of total protein in blood serum before the beginning of treatment and on the seventh and fourteenth days after beginning treatment. Research results showed that application the antibacterial veterinary drug in complex therapy with Trivitim in treatment of calves proved to be efficient. Their administration shortened the terms of recovery and prevented animal death as well as promoted the normalization of hematological and biochemical blood indexes.

There was studied the nosological profile of calve respiratory diseases and search of a complex way of preventive maintenance of respiratory pathologies with influence both on aetiology, and on the mechanism of disease development. The carried out research have allowed to draw following conclusions: among respiratory diseases at calves till 2-month age prevail diseases of the top respiratory ways (rhinitis, tracheitis, bronchitis); zinc-sulphatic is applied to complex diagnostics of respiratory diseases and predisposition to them of calves with high efficiency of the broncho-pulmonary; carrying out of preventive actions with use of an aerosol from one-chloride iodine and preparation ASD-2 leads to decrease in disease of calves by respiratory diseases and duration of their current; values of the broncho-pulmonary test applied to the control of efficiency of preventive actions, were above in trial groups at application of preparation ASD-2 on 32% and at complex application of preparation ASD-2 and an aerosol of one-chloride iodine on 37%. In the tabular form data on a clinical condition of calves are presented at respiratory diseases and dynamics of the broncho-pulmonary test at calves of trial and control groups. | Целями работы стали изучение нозологического профиля респираторных заболеваний телят и поиск комплексного способа профилактики респираторных патологий с воздействием как на этиологию, так и на механизм развития заболеваний. Проведенные исследования позволили сделать следующие выводы: среди респираторных заболеваний у телят до 2-месячного возраста преобладают заболевания верх¬них дыхательных путей (ринит, трахеит, бронхит); для комплексной диагностики респираторных заболеваний и предрасположенности к ним телят с высокой эффективностью применён цинк-сульфатный бронхолёгочный тест; проведение профилактических мероприятий с использованием аэрозоля из однохлористого йода и препарата АСД-2 приводит к снижению заболеваемости телят респираторными заболеваниями и длительности их течения; значения бронхолёгочного теста, применённого для контроля эффективности профилактических мероприятий, были выше в опытных группах при применении препарата АСД-2 на 32% и при комплексном применении препарата АСД-2 и аэрозоля однохлористого йода на 37%. В табличной форме представлены данные по клиническому состоянию телят при респираторных заболеваниях и динамика БХТ у телят опытных и контрольной групп.