The role of endotoxin in the pathogenesis of acute pneumonic pasteurellosis is uncertain. Recently, we reported that Escherichia coli-derived endotoxin given by airway inoculation fails to induce lung injury in calves. Because Pasteurella haemolytica-derived endotoxin may differ substantially from E coli in its pathogenicity, we repeated these studies with Pasteurella endotoxin. Intratracheal inoculation of P haemolytica endotoxin caused hypoxemia and increased the alveolar-arterial oxygen differences without causing hypercarbia or changes in lung mechanical properties and volumes. In contrast, IV inoculation of endotoxin caused systemic hypotension, leukopenia, gas exchange impairment, increased total pulmonary resistance, and decreased dynamic compliance. Both routes of inoculation increased serum endotoxin concentrations and were associated with areas of pulmonary hemorrhage, edema, and acute inflammation. We concluded that P haemolytica-derived endotoxin is pathogenic by IV and airway routes of inoculation, and therefore differs from E coli endotoxin in its ability to induce lung lesions in calves.

Magnesium (Mg2+) plays an important role in the regulation of a range of intracellular processes. Regulation of extracellular Mg2+ contents was studied in the anesthetized Sprague-Dwley (SD) rats. Animals were injected intraperitoneally with sodium nitrite (NaNO2), and circulating Mg2+([Mg2+]c) was observed in animals injected with NaNO2 at a dose of 10mg/kg or higher. Pretreatment with methylene blue preventd the NaNO2-induced increse in [Mg2+]c.[Mg2+]c displayed an inverse linear correlation with hemoglobin and exponential correlation during NaNO2 injection. Injection of KCN or rotenone also induced an increase in [Mg2+]c. An increase in [Mg2+]c was observed when respiration rate was reduced from 100/min (140ml/min) to 10/min (14ml/min) during 30 min. These results indicate that changes in [Mg2_]c inversely reflect alteration of ATP in a model of metabolic inhibition

In the conditions of the Republic of Belarus there was determined the influence of lactulose of the clinical state of weanling piglets, as well as analysis of its preventive and therapeutic efficacy. For the experimental group of piglets in course of 5 days before weaning the lactulose for administrated daily in combination with feed in course of 5 days in dose of 0,002 gram per kilogram of live weight. In 3-5 days after weaning the diarrhea was stated in 4,1% of experimental piglets. The clinically evident efficiency of application of the synthetic disaccharide was showed in lowering of disbacteriosis level in weaning piglets on 33,7%. Besides, there was analyzed the therapeutic efficacy of lactulose for weaning piglets diseased with gastroenteritis. They were administrated lactulose in dose of 0,03 grams per kilogram of live weight once a day after feeding in course of 7 days. Haematologic and biochemical blood indexes of experimental and control groups of piglets were analyzed. Research results showed that application of lactulose promoted the creation of optimal conditions for beneficial microflora, stimulated its reproduction, suppressed the development of opportunistic pathogens.

In the conditions of the Republic of Belarus there was studied the clinical and biochemical status of pregnant cows, as well as the determination of the main reasons of disease incidence of new-born calves with dyspepsia (dyspeptic disorder). Realized clinical and biochemical studies showed that the inappropriate feeding of pregnant cows in animal breeding farms in housing season of husbandry caused the disorders of metabolic processes in the experimental animals. In blood there was noted the lowering of indexes of alkalinity reserve, glucose, phosphorous, carotine, disturbance of calcareous and phosphorous ratio. In other words, in pregnant cows there were stated the latent forms of osteodystrophia, hypovitaminosis A, hypoglycemia, and acidosis. All these factors caused the irritation and damage of liver and other organs. Mammary gland of diseased animals released colostrum milk of low quality and according to the content of nutritious and protective elements quantity it was of low quantity. Besides, derangements in calf feeding of pregnant nonmilking cows led to birth of calves with low resistance indexes to the influence of external environment factors.