The purpose of this work was to analyze the thermal balance of easily assembled premises of different types and sizes during the periods of low average daily temperatures. The research was conducted during the winter period of 2020–2021 in the Kyiv region. The used material was easily assembled premises of different types and sizes: easily assembled ones without insulation elements; with elements of warming and premises with deep-litter. In each of the studied premises were kept 400 dairy cows. The studies were performed during two periods: the first period had ambient temperatures from -10 to -14.9 °C and the second one from -15.0 °C and below. In our studies, the average daily temperature (during the ambient temperature from -10 to 14.9 °C) in easily assembled premises with the use of insulation elements was 6.20 and 5.31 °C higher than in premises without insulation and deep-litter. A similar trend was observed during the period of lowering the ambient temperature up to 15 °C and below. Thus, the advantage of the premises without insulation constituted 6.28 °C, and of the premises with deep-litter per 5.84 °C, respectively. It was found that keeping in easy-to-assemble premises with insulation elements, the consumption of free thermal energy from the whole herd during the experimental periods was lower compared to the keeping in a boxing cowshed and a cowshed with deep litter. This is due to the smaller range of fluctuations in the average daily temperature in a room with insulation elements. A similar trend was observed for energy consumption through enclosing structures and for moisture evaporation and, accordingly, total heat consumption. In general, heat deficiency was observed during the keeping of cows in the investigated premises of easily assembled type at negative temperatures (-10–14.9 and -15 °С and above). Accordingly, the thermal balance of the premises was negative. The highest values of heat balance among easily assembled premises in both research periods were observed for keeping in rooms that used insulation elements.

To study the effect of different doses of feed additive TC VMP in the composition of complete feed granular feed on the digestibility of nutrients and retention of Nitrogen in young rabbits with intensive cultivation technology, a scientific and economic experiment was conducted. To carry out a balance experiment, four rabbits were selected from each group of test animals, which were placed individually in specially equipped cages. The experiment was performed by the method of groups in three periods: preparatory – 7 days, preliminary – 5 days, accounting – 6 days. Analysis of feed, feces, urine was performed according to generally accepted methods of zoochemical analysis. For feeding young animals of experimental groups of rabbits used complete ration granular feed, in the structure of which there was a different content of feed additives. Rabbits were fed complete feed granular feed where the content of wheat bran was – 25.7%, barley grain – 13.0%, corn grain – 5.0%, soybean meal – 2.5%, sunflower meal – 15.0%, hay flour alfalfa – 25.0%, oats – 10.0%, table salt – 0.35%. The nutritional value of granular complete feed for all experimental groups of rabbits was the same. According to the balance experiment, the best indicators of nutrient digestibility were found in young rabbits of New Zealand breed, with a feeding dose of feed additive TC VMP in the composition of granular feed – 3.5%. At this dose, the coefficient of digestibility of organic matter was 63.3%, crude protein – 67.9, crude fat – 74.1, crude fiber – 24.8 and nitrogen-free extractives – 72.3%, which increased the digestibility of organic matter by 2.5%, crude protein by 3.9% (p≤0.05), crude fat by 2.9%, crude fiber and BER by 1.9 and 2.6%, respectively, in young rabbits, with intensive rearing on meat. It was found that in the body of animals of the experimental group, which were fed as part of the feed additive of TC VMP in the amount of 3.5%, the ratio between the amount of nitrogen absorbed from the consumed rabbits of this experimental group was dominated by animals from the control group by 2.92% 0.05). Thus, research data indicate a positive effect of feed additive TC VMP on the growth and development of young rabbits of New Zealand breed. Key words: digestibility coefficient, young rabbits, compound feed, organic matter, protein, fat, fiber, copper.

No abstract

The problem of complete mineral and vitamin nutrition in rabbit breeding is relevant today, despite new discoveries, and research in this direction continues both in Ukraine and around the world. The paper presents experimental data from the results of research to study the effect of different doses of vitamin and mineral supplement "Tekro" in the diets of young rabbits on their productivity, slaughter quality and biological value of rabbit meat. The obtained data of body growth, massometric indicators of carcasses and internal organs of rabbits of experimental groups after slaughter indicate a positive effect of vitamin-mineral supplement "Tekro" on the intensity of development of the body and individual internal organs, which contributes to increased metabolic processes and weight gain in animals research groups. Feeding vitamin and mineral supplements to rabbits of experimental groups of the New Zealand breed for 45 days contributed to a better transformation of feed nutrients into products. In rabbits of the 3rd experimental group, which together with basic ration were fed 3.5 % of the premix "Tekro" at 90 days of age, the highest rates of body weight were recorded, which differed by 8.89 % compared to the control group. In a set of indicators that characterize the nutritional value of rabbit meat, we studied sensory indicators that characterize the quality of rabbit meat: taste, color, pH, juiciness, moisture content, elasticity, aroma, "marbling", etc. It was found that in the appearance of carcasses and muscles in the control group, the samples scored 8.4 points. In the 3-rd and 4-th experimental groups, the number of points on this indicator was higher by 1.2 %. The difference was a trend. Examining the aroma of meat, it was found that in the control of this indicator, the samples scored 7.8 points. In meat samples from experimental groups 3 and 4, the aroma was more identical to natural, so the samples received 2.6 % higher scores. Samples from 3 experimental groups scored the most points in terms of taste. Compared with the control, the figure was higher by 3.6 %. Examining the juiciness of rabbit meat, it was found that samples obtained from carcasses 2 and 3 of the experimental group tended to increase this indicator. Summing up the data, it was found that the highest overall score was found in meat samples from 3 experimental groups. The difference with the control was within the trend and amounted to 2.4 %. Feeding rabbits vitamin and mineral supplements to rabbits helps to obtain good quality meat products with high culinary properties. No data were available to support the effect of vitamin and mineral supplements on compound feed on the synthesis of toxic substances in muscle tissue or the deterioration of rabbit meat. The biological value of muscle samples from rabbits of the 2-nd experimental group did not differ from the control data. The increase was only 0.11 %. It was found that the biological value of muscle tissue from animals of the 4th experimental group was greater than in the control. The difference was 2.6 % Meat obtained from rabbits of the 3rd experimental group, which were fed compound feed with a content of mineral-vitamin supplement "Tekro" 3.5 %, in biological value outweighed the control indicators. The difference was not significant and amounted to 4.1 %. The use of different doses of vitamin and mineral supplements in the feed of young rabbits did not lead to significant changes in the quality of raw hides and furs.

One of the pressing problems of modern biochemistry is the problem of adaptation of animal organism to the environment and the formation of an adaptive reaction to the negative impact of production stress factors. Among such adaptive mechanisms for rabbits in the conditions of intensive rabbit meat management is the development of oxidative stress, which causes the accumulation of reactive oxygen species in the body and the development of reactive oxygen pathology. An important role in the mechanism of adaptation of the body belongs to lipids, because they are a structural component of cell membranes and act as energy and signal systems in cells. Peroxide oxidation of lipids is a compensatory reaction that ensures the functioning of the organism for changes in the environment. The content of total lipids and peroxide oxidation products of lipids, as well as the activity of enzymes of the antioxidant defense system in rabbits from birth to 90 days of age was investigated. It has been established that the content of total lipids in brain tissues increases throughout the period of postnatal ontogenesis due to the peculiarities of the functional and metabolic activity of brain cells. The content of common lipids is closely related to the processes of lipid peroxide oxidation and the activity of enzymes of antioxidant defense. The growth in concentration of peroxide oxidation products is accompanied by a decrease in the content of total lipids in the rabbit tissues. Reduced content of TBARSproducts in rabbit brain tissue from birth to 90-day age was noted. A moderate (r = 0.66) correlation between the content of lipid conjugated dienes and lipid hydroperoxides, as well as the strong correlation (r = -0.77) between the contents of lipid conjugated dienes and TBARS-products has been established. In the heart of rabbits a reversible moderate (r = -0.62) correlation between the content of lipid conjugated dienes and lipid hydroperoxides has been revealed. Key words: rabbits, development, lipid peroxidation, brain, heart, longest muscle of the back.