In the conditions of the Republic of Belarus there was studied the possibility of application of biotechnological methods of correction of sexual function of infertile cows and heifers (oestrus stimulation and synchronization) a dairy cattle breeding farms with high breeding productivity indexes and simultaneous metabolic function diseases. In course of the study there were applied clinical, cytodetection technique, haemotological, biochemical and analytical methods. Results of three-year studies of pathological metabolic disorders of cows (chronic acidosis; chronic ketoacidosis; dystrophic liver affection; renal irritation syndrome; disturbance of calcium and phosphorous ratio; trace element deficiencies; hypovitaminoses) were analyzed. Structure of obstetric-gynecologic pathology in experimental dairy cows herd was presented. Research results showed that high reproduction indexes of cows were the contributory cause for development of metabolic disorders. In such conditions for the efficient stock reproduction it was proposed to apply the mandatory hormonal stimulation of sexual function by means of application of the Ovsinkh scheme.

In the conditions of the Republic of Belarus there was presented a characteristic of breeding stock of mares of Trakensky breed in accordance with body conformation and exterior. In course of the study there were taken measurements of height at the shoulder, heart-girth, metacarpus circumference at 1 year old and two year old age stages. There was calculated an index of massiveness which characterize the development of chest, index of bone which provided insight into skeleton development. Research results showed that in accordance with an exterior the breeding stock mares had a deep and massive barrel, good skeleton and developed muscle. The index of massivness was 118,4-120,5, bone index – 20,8-21,6, that corresponded to a type of riding horses. In accordance with the exterior, measurements and quality of posterity the mares of the bred lines obtained high grades and 93,5% were graded as elite class.

In the conditions of the Republic of Belarus there was determined the influence of different rates of lithium addition into mixed fodders for sows feeding on hematological indexes and their reproductive qualities. In course of the study there was analyzed the dynamics of body weight of sows over the reproductive period; indexes of productivity of sows (number of born piglets; weight of 1 piglet; litter weight; weight of weanling piglets; number of weanling piglets; etc.); hematological indexes of sows; state of humoral factors of immunity of sows. Research results showed that in case of lithium application in diets of sows there was stated an improvement of hematological indexes and immunity functions and resistance. The optimal level of lithium in rations was 15 milligram per 1 kilogram of dry matter of a diet. This dose essentially promoted the increasing of reproductive performance, piglets weight and milking capacity of sows as well as better viability of piglets.