In the conditions of the Republic of Belarus there was analyzed the influence of the following paratypical factors on cow productive longevity: age of the first calving; milk yield at the first lactation; and a birth season. At the experimental animals there studied the indices of dairy efficiency: a lifelong milk yield (kg); a lifelong yield of dairy fat (kg); the total duration of the lactation period (days); duration of practical use (lactations). There was noted a tendency of increasing of a term of productive use and lifelong productive efficiency at the animals the practical economic use of which was begun in later terms. The insemination of these animals was approximately realized at the age older than 21 months. Also it was stated that in accordance with all investigated indices (except for a milk yield per one day of lactation) the highest indexes were typical for cows which had the least milk yield at the first lactation.

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.

Results of determination of yielding capacity, chemical composition of initial weight and silage quality of forages prepared from the binary mixtures of Japanese millet (Panicum curs-galli var. frumentaceum), millet (Panicum) and saccharine sorghum (Sorghum saccharatum) realized in the conditions of the Republic of Belarus were presented. Research results showed that the binary mixture of saccharine sorghum with blue lupine (Lupinus angustifolius) in ratio of 70% + 30%, respectively made it possible to obtain the highest efficiency (62,4 t/ha of green material, 15,1 t/ha of dry matter, 13,1 t/ha of fodder units). Mixed sowing of millet, Japanese millet and saccharine sorghum with blue lupine surpassed in productivity the single-crop sowing on 15,5-32,6%. It was established, that the silage produced from the mixture of sorghum and Japanese millet with lupine had higher energy and protein nutritive value: 0,86 and 0,98 fodder unit, respectively; 9,77 and 9,92 mJ of exchange energy per 1 kg of dry matter, respectively; 103, 3 and 108,4 grams of digestible protein per 1 fodder unit. High nutritive value and the best palatability of trial silos promoted the increasing of milk yield on 4,4-5,4% in comparison with the control tests. Haylage which was produced from drought resistant crops had high energy nutritive value: per 1 kg of dry matter there was noted 9,40-9,48 mJ of available energy, 0,89-0,94 fodder units with fodder unit provision with 102-114 grams of digestible protein

Evaluation of maize (Zea mays) silage prepared in combination with biological preserving agent Laktotim and calculation of its economic efficiency were realized in the conditions of the Republic of Belarus. Application of Laktotim rendered positive influence on forage dry matter content, on nutritive substance safety, and made it possible to increase the organoleptic indicators of silage. Use of the maize silage prepared with the preservative in a cow ration has positively affected their dairy efficiency. Cow milk yields have raised on 4,5%. Application of the preparation for silage making of green maize mass proved to be economically worth. The realized toxicological estimation of biological preserving agent Laktotim did not reveal any signs of preparation toxicity. Introduction of the preparation into mice stomach in a single maximum dose (25000 mg/kg; 12500; 5000 mg/kg of body weight), as well as application of the preparation in mixture with water in ratio which in 100 and 200 times exceeded the standard ratio in plant green mass, did not cause destruction of experimental animals. According to classifications of All-Union State Standard 12.1.007-76, the preparation Laktotim belongs to the4 class of danger - low-hazardous substances (LD50 over 5000 mg/kg)

In the conditions of the Republic of Belarus there was developed a production technology and there were produced samples of lyophilizated live vaccine against Aujeszky's disease of swine which corresponded to all parameters of control. The vaccine had an expressed phylactic power, induced the development of long-lived immunity of vaccinated piglets.