In the conditions of the Republic of Belarus there was analyzed the metabolic status of cows in the finishing period of pregnancy, as well as influence of its disorders on clinical status and breeding and economic indexes of new-born calves. Research results showed in pregnant cows in interlactation period there was stated the development of subclinical poly-hyper trace element deficiencies. There was realized the analysis of indexes of trace elements metabolism in cow blood; blood indexes characterizing protein metabolism; as well as biochemical blood indexes characterizing the carbohydrate metabolism and functional state of liver and kidneys. In the conditions of subclinical poly-hyper trace element deficiencies of cows there were revealed the biochemical changes which showed the lowering of the functional activity of liver and intoxication. Economic and clinical indexes of calf crop were analyzed. Research results showed that in calves (obtained from cows with trace element deficiencies) in an early extrauterine life there statedthe development of a toxic form of dyspeptic disorder which was accompanied with high degree of young stock death.

Data on development of an antigen on the basis of larvae of warble flies grubs (Hypodenna bovis) for diagnostic of spontaneous cattle hypodermosis by means of the indirect fluorescent (IFA) test and with application of blood serum and milk samples realized in the conditions of the Republic of Belarus were presented. Specificity and sensitivity of experimental sample of antigen for revealing of spontaneously infestated with larvae of warble flies with IFA test at hypodermotosis has made about 100%.

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.

Study of subclinical chlamydial endometritis of black and motley cows of 2-5 lactations with 5000-6000 kg milk per year was realized in the conditions of the Republic of Belarus. Research results showed that reaction of pH medium of uterus content of healthy ill cows with subclinical chlamydial endometritis did not change and was within the limits of 8. Diagnostics of subclinical chlamydial endometritis during estrum was realized according to presence of estrous mucus in purulent inclusions, as well as of neutrophil in tissue smear and by colouring by Stamp of tissue smears from a uterine lining and in serological reactions. In inter-estrous cycle it was possible to establish a latent chlamydial endometritis according to slightly opened uterus channel, state of uterus walls and presence of yellow bodies in an ovary, increasing of titers in antibodies in two and more times in dual tests of serum.

Development of highly efficient antigens for an early immunodiagnosis of cattle fascioliasis (Fasciola hepatica) and studying of its main properties was realized in the conditions of the Republic of Belarus. Received in result of the experiment antigens possessed high specificity and were suitable for use in fascioliasis immunodiagnostics. Research results showed that use of indirect fluorescent (IFA) test and immunodiffusion test for fasciolasis immunodiagnostics of cattle excludes false positive results caused by tuberculosis and hypodermotosis (p less than 0,001).