Currently, much attention is paid to various groups of bacterial cultures that are used in poultry farming in the form of mono-additives or in combination with biologically active substances. The purpose of the research was to compare the productivity of rearing of replacement chicks and laying hens of the parental herd and the use of probiotic feed additives Levisel SB Plus and Cellobacterin-T in their diet. The researches have been performed under conditions LLC “Ravis – poultry farm Sosnovskaya” in the Troitsky district in the Chelyabinsk region on the cross of poultry “ISA-Hubbard-F15”. The research has made it possible to expand the theoretical understanding of the periodic use of probiotic feed additives in the diet of egg productivity poultry. The addition of probiotics with their periodic inclusion in the diet has a positive infl uence on the egg production of poultry throughout the productive cycle with a noticeable superiority of Cellobacterin-T over Levisel SB Plus. The inclusion of the probiotic Cellobacterin-T in the diet of replacement chicks and laying hens at a dosage of 0,50 kg/t of complete feed allows us to enhance the homogeneity of the group in the period of rearing of replacement chicks, and its inclusion in the diet of laying hens has increased egg production by 9,2 %, the hatching rate by 2,2 %, the livability of poultry by 1,9 %, profi tability of production 7,6 %. Therefore, it is economically advantageous to use probiotic feed additives in the diet of laying hens of the parental herd not during the entire productive cycle, but during the most stressful periods associated with preparing the poultry for egg laying, at peak and when it decreases.

The rearing of young animals is an important and fundamental stage in obtaining highly productive animals. The traditional technology of calves rearing in typical heated rooms provides for significant costs for their heating, ventilation, manure removal and feeding. The purpose of the work was to study the productive traits of calves depending on the method of their rearing. Research has been carried out to study the influence of different conditions of housing calves during the preweaning period under conditions in the farm “Ershov” (Vykhodnyi village) in the Buguruslansky area in the Orenburg region. The influence of housing methods on the dynamics of live weight, morphological and biochemical parameters of blood, conformation characteristics and body type indices of replacement heifers has been established. During the entire study period the average daily gain in calves of the experimental group was higher by 66 g or 9,4 % (P < 0,05), live weight by 7,0 kg or 6,9 % (P < 0,05). There was no significant difference in the morphological and biochemical parameters of the blood of the experimental calves. At 3 months of age the animals of the experimental group had superiority in all the measurements taken: in height at the withers by 2,0 cm or 2,2 % (P < 0,05), height in the rump bone by 0,5 cm or 0,5 %, length of the body by 2,8 cm or 3,1 %, chest width by 0,9 cm or 3,6 %, chest depth by 1,5 cm or 3,9 %, chest circumference by 2,0 cm or 1,9 %, width in hook bones by 0,4 cm or 1,8 %, hip joint width by 1,1 cm or 5,4 % (P < 0,05), rump half–circumference by 1,0 cm or 2,2 %, pastern circumference by 0,1 cm, or 0,8 %, compared with the corresponding indicators of calves of the control group.. Similarly, the calves of the experimental group had superiority over the analogues of the control group in terms of body type indices. Thus, according to the thoracic index the calves of the experimental group outperformed their herdmates by 9,2 abs.% (P < 0,01) and according to the meatness index they outperformed the herdmates of the control group by 3,5 abs.% (P < 0,05).

A rational system of rearing young animals taking into account the biological characteristics of animals should contribute to normal growth, development, formation of high productivity and a strong constitution, prolonging the terms of economic use of livestock. The purpose of the research was to analyze the rearing of replacement heifers during the preweaning period when using bentonite clay as a mineral supplement in diets. Three groups of heifers were formed to conduct research. Bentonite was introduced into the diet of the heifers of the 1st experimental group at the rate of 1 % of the compound feed composition, the heifers of the 2nd experimental group were input with 2 % bentonite into the compound feed, and the heifers of the control group did not receive bentonite. In the course of research an analysis of the infl uence of bentonite on the growth and development of heifers of Black-and-White breed up to 6 months of age in the winter period of their rearing was given. The feeding diets of heifers from birth to 6 months of age monthly were presented in the paper. It was found as a result that bentonite introduced into the diet of animals of experimental groups allowed to increase the digestibility and accessibility of nutrients in the diets. Thus, the coeffi cient of digestibility of dry matter in the heifers of the control group was lower compared with the herdmates of the 2nd experimental group by 2,02 abs.%. The organic matter of the animals of the control group digested less compared to the 1st experimental group by 0,29 abs.%, and from the 2nd group by 2,17 abs.% The coeffi cient of digestibility of crude protein in the 1st experimental group was by 0,65 abs.% less, and in the 2nd experimental group 1,63 abs.% (p < 0,05) more than in the control.

A rational system of rearing of replacement heifers taking into account their biological characteristics, should contribute to normal growth, development, the formation of high productivity and a strong constitution, and the extension of their longevity. The use of intensive rearing has a positive eff ect on the natural resistance of replacement young cattle. The purpose of the researches was to analyze the use of bentonite clay as a mineral additive in the rearing of young cattle. Scientifi c and economic experiment has been carried out on heifers of Black-and-White breed in the pasture period. Two groups of heifers have been formed based on the principle of analogous pairs, taking into account their origin, age, body weight and health status. Animals of both groups have been received the main economic ration during the rearing period, while heifers of the experimental group have been received a bentonite additive of 50 g (2,0 %) per head per day, control animals did not receive this additive. Experiment has shown that the experimental animals had a high growth rate. Up to 3 months of age the live weight of animals in both groups increased almost evenly. The average daily gain was in the range of 600–900 g. At the age of 4 months the average daily gain in body weight was 550 g in the control group, and 800 g in the experimental group. The diff erence between the groups was 250 g or 45,45 %. The highest average daily gain at the age of 6 months was in the animals of the experimental group and amounted to 1060 g, which was by 127 g or 13,61 % more than in the control group. Feed costs in the control group amounted to 6411,92 rubles, in the experimental group 6392,22 rubles, which was 19,70 rubles or 0,31 % less than in the control group. Thus, there were no signifi cant diff erences in the cost of feed between the groups. The prime-cost of 1 kg of live weight gain of heifers in the experimental group was less by 7,02 rubles or 9,26 %. In general, the level of profi tability of rearing of heifers in the experimental group was higher by 12,11 %, compared to the control group.

It is assumed that the combined effect of an effective probiotic and feed bentonites will enhance their positive effect on the growth, development, immunity of poultry, the quality of products, economic results of production. The purpose of the research was to study the effectiveness of the probiotic Vetkor and trace elements contained in bentonites in the compound feed of broiler chickens. Scientific and economic experiment has been carried out in the company “Uksyansky broiler” on broiler chickens cross “Smena-4”, which have been distributed in 3 groups on the principle of analogues. For each group 50 heads have been selected one day-old chickens. The conditions for rearing and housing the chickens were the same. The joint use of bentonite and probiotic in rearing and fattening broiler chickens have been studied. At the beginning of rearing the weight of chickens in all groups was almost the same and averaged 39,6 g. However, with increasing age of chickens not only their live weight increased, but also the difference between groups for this indicator. So, at the age of 7 days the chickens of the 1st experimental group had live weight higher than the control ones by 1,86 %, and the chickens of the 2nd experimental group by 2,00 %. The live weight of the broiler chickens of the control group at the end of rearing (age 42 days) was less than the live weight of the 1st broiler chickens of the experimental group by 101,14 g or 5,23 % (P < 0,05), and the 2nd experimental group by 132,14 g or 6,83 % (P < 0,01). The total and average daily increase in live weight of chickens of the 1st experimental group was greater by 5,34 % (P < 0,05), and the 2nd experimental group by 6,96 % (P < 0,05) than in the control group. Broiler chickens that consumed the probiotic Vetkor in the compound feed had higher growth energy than in the control. Against this background the best growth has been observed in broiler chickens of the 2nd experimental group who consumed compound feed with the addition of Vetkor and 3 % bentonite. It has been experimentally justified the use of probiotic and bentonite in the industrial production of meat of broiler chickens, it has been established a positive effect of probiotics and bentonite on the growth and development of broiler chickens, the quality of the resulting products.