It was established that in blood serum of pigs vaccinated against leptospirosis there was an authentic increasing of alanine aminotransferase, alkaline phosphatase and gamma-glutamyltransferase that made proved the presence of residual reactogenicity of biological preparations. In course of the experiment there were used 4 groups of swine which were administrated with 4 types of vaccines: 1. polyvalent vaccine produced in Belarus; 2. experimental thiosulfate vaccine in which there was used 30% sodium solution; 3. experimental emulsified vaccine; experimental emulsified + sodium + thiosulfate vaccine.

The research directed on perfection of a cattle protein food system, taking into account its fractional structure, and also establishment of objective indicators of an estimation of forage protein nutrient density, have great value. It is established, that for young growth of cattle of 4-6 months of age the optimum parity of decomposable and un-decomposable protein in rations corresponds to size 68:32, allowed to raise digestibility of nutrients on 3-4%, nitrogen adjournment in an organism of animals on 10% and daily average a gain on 4% in comparison with parity 80:20. The optimum parity of fractional structure of protein makes positive impact on oxidation-reduction processes in organism to what testifies morphological-biochemical structure of blood. Thus concentration of crude protein raises on 1,7%, urea quantity decreases on 23%. The least cost price of a gain has appeared in group with a parity of decomposable and un-decomposable protein in rations 68:32, or it is better on 4,4% than an indicator of group with a parity 80:20%

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.

This article is devoted to a problem of biochemical interaction of selenium and antioxidational system of animals and people organism. The problem we have touched is about the efficiency of influence of organic and inorganic taking place on subcellular level. The advantages of organic selenium are proved, the degree of its bjochemical influence on an antioxidationi status of health are indicated.

In the conditions of the Republic of Belarus after fasciolosis invasion of cattle for the biochemical diagnostics of liver pathologies there was composed a hepatospecific metabolic profile of blood serum of cattle into which there were included several enzymes (alanine aminotransferase; aspartate aminotransferase; gamma-glutamyl transpeptidase; alkaline phosphatase; and cholinesterase), content of total albumin, serum albumin, total cholesterin and total bilirubin, as well as colloid tests (thymol turbidity test and test for apoliproteins). There was revealed a intrahepatic cholestasis developed during fasciolosis infestation, as well as dysproteinemia as a compensatory mechanism of liver proteinsyntetic function.