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.

Comparison of morphological changes in placenta in the conditions of physiological pregnancy and pregnancy complicated acute asphyxia in farrow with deadborn piglets was realized in the conditions of the Republic of Belarus. There were realized complex clinical and morphological studies of placenta of pregnant sows. The experimental group was formed by pegnant sows with intranatally dead fetus because of acute asphyxia in course of farrowing caused by abnormality in placental circulation(prolapse of funis or loop of cord). The second (control) group consisted of healthy bred sows with physiological farrowing and alive newborn piglets. The groups were comparable to age, number of farrowings (no more two) and housing conditions. Detailed macrographic examinations of placenta (form, size, square, weight, volume, fetus-plecentary coefficient, amnion status and so on) and cord were realized. The research result showed that in the conditions of a complicated pregnancy in the thickness index placenta there were visualized a lot of connective tissue changed locus, infarcts as well as areas, and changes in morphometric indexes. All mentioned above factors proved to be a morphological substrate of fetoplacental insufficiency, which subsequently caused asphyxia, hypoxia, small-for-gestational-age fetus, and dead birth