Pre-slaughter Live Weight Research Articles

ЭФФЕКТИВНОСТЬ БИОКОНВЕРСИИ ПИТАТЕЛЬНЫХ ВЕЩЕСТВ И ЭНЕРГИИ КОРМА В МЯСНУЮ ПРОДУКЦИЮ БАРАНЧИКАМИ РАЗНОГО ГЕНОТИПА

The purpose of the study is to determine the influence of the genotype of rams on the efficiency of transformation of protein and energy of the feed ration by purebred young animals of the Romanov breed (Group I), its crosses with the Edilbaevskaya breed of the first generation 1/2 Romanovskaya × 1/2 Edilbay (II group) and the second generation 1/4 Romanovskaya × 1/4 Edilbay – ( Group III) in food protein and energy of meat products. Crossbreeds of groups II and III were distinguished by less crude protein consumption per 1 kg of live weight gain than peers of group I – by 15.9 (1.62 %) and 33.5 g (3.48 %) and energy by 3.64 (4.23 %) and 4.89 mJ (5.77 %). An advantage was noted for crosses of groups II and III in terms of the weight of edible parts of the carcass, which amounted to 5.05 (36.89 %) and 6.79 kg (49.60 %). Purebred rams of group I were inferior to crossbred young animals of groups II and III in terms of protein content in the edible part of the carcass by 0.86 (31.62 %) and 1.15 kg (42.28 %), respectively, extractable fat – by 0.82 (66.13 %) and 1.25 kg (100.8 %), energy – by 46.54 (49.01 %) and 68.30 mJ (71.93 %). All this determined the advantage of crossbred rams of groups II and III in terms of the yield of nutrients, edible parts of the carcass and energy per 1 kg of pre-slaughter live weight. For protein, this advantage was 2.49 (3.53 %) and 4.32 g (6.12 %), extractable fat – 9.86 (30.65 %) and 16.01 g (49.77 %), energy – 0.59 (23.98 %) and 0.70 mJ (28.45 %). The advantage of crossbred young animals of groups II and III in terms of the protein bioconversion coefficient was established, which was 0.26 and 0.65 % for protein, 0.21 and 0.40 % for energy, respectively. The leading position in all indicators was noted for crossbreeds of the second generation of group III.

Effect of the complex supplement «Gepasorbex» on the amino acid composition of muscle tissue of pigs

The modern pig breeding is focused on the constant improvement of pig housing conditions, ensuring high quality and safety of products, using effective feeding and breeding technologies, as well as the balanced consideration of ecological and economic aspects. New methods of rearing andfattening pigs affect not only the quantity, but also the quality of the slaughter raw materials obtained. Objective. To study the effect of the complex supplement "Hepasorbex" on the amino acid composition of the studied groups of pigs in the conditions of a commercial enterprise in accordance with the industrial technology. Methods. On the basis of the above, for the assessment of slaughter qualities, young animals were selected for slaughter from groups offattening young animals when piglets reached a live weight of 100 and 120 kg in the amount of 10 heads of each weight condition under the conditions of the limited liability company "Tavriiski Swyni". Next, it has been studied the effect of the complex supplement "Hepasorbex" on the amino acid composition of the muscle tissue ofpigs of experimental groups with a pre-slaughter live weight of 100 and 120 kg in the amount of 5 samples of each group. Results. It was revealed the deep changes in the animal body: in particular, in the amino acid composition of muscle tissue (replaceable, essential amino acids and their ratio) by detailed researches. Thus, 100 g of muscle tissue protein obtainedfrom the carcasses of pigs of the III research group: for pre-slaughter live weight of 100 kg, contains 9.11 g of essential amino acids and 11.43 g of replaceable amino acids, the amino acid index is 79.7 %; for pre-slaughter live weight of 120 kg - essential amino acids - 10.41 g, replaceable - 13.83 g, amino acid index - 75.27 %. The animals of the III research group are characterized by the maximum value of the protein-quality index at slaughter both at 100 kg and at 120 kg - 12.22 and 7.39, respectively, that is, "Hepasorbex" contributed to the biosynthesis of meat of better quality. Conclusions. According to the general zootechnical requirements, the protein-quality index (oxyproline, tryptophan and their ratio) of the III research group corresponds to high-quality pork (7.39 - 12.22), while the II research group (7.02 - 11.58) and the I control group (6.7 - 12.21) meet the requirements ofpork of normal quality. Keywords: technology, pigs, feed additive, amino acid rate, replaceable amino acids, essential amino acids, protein-quality index.

Effect of mineral feed additive on egg productivity of laying hens

Improving the consumption and increasing the efficiency of the use of feed, obtaining maximum egg productivity is ensured by a high level of balanced feeding with various feed additives. Therefore, the research work aimed to study the effect of mineral feed additives on the egg productivity of laying hens of the Loman Brown cross. During the experiment, the control group of laying hens consumed the basic ration (BR) – complete combined feed. In feeding the research group, a mineral selenium-containing feed additive was used with the main diet. Selenium in the feed additive is contained in organic form, selenomethionine and selenocystin. Unlike inorganic forms, selenoamino acids can be transported and metabolized in the body to build amino acids. According to the results of the experiment, it was found that when feeding mineral feed additive, there was an increase in the gross collection of eggs in laying hens of the 2nd group by 12.7 % (Р ≥ 0.01) and a decrease in feed consumption by 10 pcs. eggs by 9.0 %, relative to the control group. In addition, there is a tendency to increase the laying rate per average laying hen by 9.5 % and the laying intensity by 3.9 %. With the additional use of the mineral feed additive by laying hens of the 2nd group, the mass of eggs increases by 5.3 % (Р < 0.05), the height of the yolk by 25.0 % (Р < 0.05), and the yolk index by 0.06 % (P < 0.01) versus the control value. It was established that the use of mineral supplements by laying hens of the 2nd group increases live weight by 5.1 % (Р ≤ 0.05), absolute gain by 12.3 % (Р ≤ 0.01), pre-slaughter live weight by 5.7 % (Р ≤ 0.05), the weight of the semi-cartridge by 4.3 % (Р ≤ 0.05) and the weight of the carcass by 11.5 % (Р ≤ 0.01) against the reference indicator. Under the influence of the mineral feed additive in the 2nd group of laying hens, the survival rate of the flock increased by 3.0 % compared to the control analogs.

Productivity of broilers using a mineral feed additive

The effectiveness of increasing the productivity of agricultural poultry depends on the extent to which production technologies enable the realization of its genetic potential. The experiment aimed to study the effect of a mineral feed additive containing copper on productivity, growth, and feed consumption in broiler chickens. The scientific and economic experiment was conducted in the conditions of the Vinnytsia National Agrarian University vivarium. For the experiment, 40 broiler chickens of the “Ross-308” cross were selected, and two analog groups of 20 heads each were formed. The experiment lasted 42 days. During the experiment, the broilers of the 1st control group consumed a completely balanced feed. In addition to the diet of the research group, the researched mineral feed supplement was added. Broiler chickens were weighed every week to determine the intensity of growth. According to the results of the experiment, it was established that additional feeding of a mineral feed additive to broiler chickens of the 2nd group increases live weight at 21 days of age by 4.6 % (Р ≤ 0.05), at 28 days of age by 7.1 % (Р ≤ 0.01) in 35 days by 9.5 % (Р ≤ 0.001) and in 42 days by 9.4 % (Р ≤ 0.001), against the control. It was found that with the use of a mineral additive in broilers of the 2nd group, feed consumption per 1 kg of growth is reduced by 7.8 %, compared to the control value. Additional consumption of the researched mineral feed additive in broiler chickens of the 2nd group increases the pre-slaughter live weight by 8.9 %, the weight of non-carcasses by 9.7 % (Р ≤ 0.001), half-carcasses by 10.8 % (Р ≤ 0.01) and patranoi by 13.0 % (Р ≤ 0.001), relative to the control. Feeding the mineral supplement to broilers of the 2nd group increases the mass of pectoral muscles by 9.2 % and thigh muscles by 10.8 % (Р ≤ 0.01), against the control indicator.

Meat qualities of crossbred young pigs

Relevance. Interbreeding and hybridization are important factors in increasing pig productivity. As a result of the heterosis effect, the multiplicity of sows increases, the safety of offspring increases, the growth rate of young animals improves, the quality of meat improves and, as a result, the profitability of the pig industry increases.The paper presents an assessment of the meat qualities of local young pigs obtained as a result of industrial three-breed crossing.Methods. To implement the scientific and economic experience, three groups of sows of pairs of analogues of a large white breed from the Hypor company (KB Hypor) were formed. Sows of the 1st group were crossed with boars of the Landrace breed from the PIC company (Landrace Pic), the 2nd — with boars of the Landrace breed from the Genesus Genetics company (Landrace Genesus), the 3rd — with boars of the Landrace breed from the Hypor company (Landrace Hypor). As a result, two-breed crossbreeds (F1) were obtained. Next, crossbred sows (F1) of the 1st, 2nd and 3rd experimental groups were crossed with boars of the Duroc breed from Genesus Genetics, as a result, commercial young (F2) were obtained.Results. According to the research results, it was found that the highest pre-slaughter live weight was obtained from animals of the 1st group (125.12 kg), which is more than in the 2nd and 3rd experimental groups, respectively, by 5.8% and 4.0%. Studies of the chemical composition of the longest back muscle of young pigs showed that the protein content in all meat samples was in the range of 23–24% with a minimum value (23.31%) in the muscle tissue of animals of the 3rd experimental group, and the maximum (23.7%) in the 1st experimental group (the difference was 0.39%). The amount of intramuscular fat in the meat of animals of the 1st (5.57%) and 2nd (6.30%) groups was significantly higher by 1.23% and 1.96%, respectively, compared with analogues of the 3rd group. The minimum pH level of meat was noted in the 1st experimental group (5.51 pH units), the maximum — in the 2nd experimental group (5.56 pH units), the difference was 0.05 pH units. The largest mass fraction of collagen (1.11%) was obtained in the 3rd group, the smallest — in the 1st experimental group (0.66%), the difference was 0.45%.

Assessment of the influence of testosterone concentration in blood serum on meat productivity and meat quality of Aberdeen Angus bulls

The studies were carried out on Aberdeen Angus bulls at the age of 18 months. The animals, depending on the level of somatotropin in the blood serum, were divided into three groups using the percentile method: group I – up to the 25th percentile; Group II – within the 25-75 percentile; Group III – above the 75th percentile. Testosterone content was determined in blood serum by enzyme immunoassay using an automatic microplate analyzer Infinite F200 PRO. To study the meat qualities of the bulls, a control slaughter was carried out. It was established that bulls with the maximum concentration of testosterone in the blood serum were superior to individuals with the minimum concentration in pre-slaughter live weight by 3.4% (P≤0.05), in fresh carcass weight by 4.7% (P≤0.05), slaughter weight – by 3.6% (P≤0.01), pulp weight – by 5.4% (P≤0.05), protein accumulation in pulp – by 8.3% (P≤0.05), dry matter content – by 0.24% (P≤0.05), protein concentration – by 0.65% (P≤0.05), protein quality indicator – by 1.3% (P≤0.05) ). At the same time, they were inferior to them in weight and yield of internal fat by 12.1 (P≤0.001) and 0.6% (P≤0.05), respectively, in terms of bone content in the carcass - by 0.63% (P≤0 .05), relative fat content by 0.84% (P≤0.05).

Formation of meat productivity in descendants of Kalmyk breed improver bulls

The article analyzes the results of assessing by scoring and index methods the quality of the offspring of five Kalmyk breed bulls and their sons in terms of their own productivity and the formation of their carcass morphological composition. For this purpose, 10 sons of bulls Prometheus 1127, Grilyazh 916, Gomat DRZh-59223, Yago DRZh-39023 and Raskat 8692 were selected from the Solnechnoe Breeding Plant LLC, Oryol district, Rostov region. The sons of the evaluated stud bulls up to 8 months of age were raised on full suction with mothers, and from 8 to 15 months of age were kept in the same group under equal conditions and over a 7-month period, on average, feed was consumed per bull, containing 1569 feed units, 168 kg of digestible protein, 2032 kg of dry matter with exchange energy 15663 MJ. With this level of feeding, all the controlled sires and almost all of their sons, according to the score, met the requirements of the elite-record grading class. However, according to the results of the index assessment, only the bulls Prometheus 1127 and Grill-yazh 916 met the requirements of the improver category, and the remaining three bulls met the requirements of the neutral category. The descendants of the leading bulls with a preslaughter live weight of 412.1 and 419.9 kg exceeded peers of other groups in carcass weight by 8.5-14.1 kg, in muscle tissue weight by 9.4-15.4 kg, but by 3-5% less yield of fat, bones, cartilage and tendons and the highest meat ratio.

Использование подкислителей и бутиратов в составе рационов – путь к реализации биоресурсного потенциала цыплят-бройлеров

Abstract. In the conditions of the research and production laboratory of the ERC “Agrotechnopark” of the Belgorod State Agrarian University, a scientific and economic experiment was carried out to study the effect of feed additives acidifier “AsidLak” and “ButiPERL” calcium butyrate on slaughter indicators, morphology of broiler carcasses, chemical composition of pectoral and leg muscles, organoleptics of meat and broth. Methods. Chickens of the 1st experimental group were introduced into the main diet of the acidifier “AsidLak” in the amount of 5 kg/t, the 2nd experimental group was injected with 0.3 kg/t of calcium butyrate “ButiPERL”, the 3rd experimental group – a complex of feed additives in dosages 1 and 2 of the experimental groups without the introduction of antimicrobial drugs; broiler chickens of the control group received a complete mixed feed (OP). When growing chickens, a three-phase feeding system was used. During the experimental period, broiler chickens were grown outdoors, under the same conditions. According to the results of the study, it was found that broilers of the 3rd experimental group had the highest pre-slaughter live weight in comparison with the control by 104.67 g or 4.0% (P ≥ 0.95), which is also higher than analogues 1 and 2 experimental by 14 g (0.51%) and 48 g (1.76 %); broilers of the 3rd experimental group had a greater mass of gutted carcass – 1870.73 g, which is higher compared to the control group by 132.96 (7.65 %), and also 1 and 2 experimental by 43.93 g (2.35 %) and 77.96 g (4.17 %). 68.7 %. An increase in the content of dry matter, fat and protein in the pectoral and leg muscles, as well as an improvement in the taste and biological value of meat was noted. The scientific novelty lies in the fact that for the first time on the livestock of the Ross-308 cross, an acidifier and butyrate were used in combination as an alternative to antimicrobial drugs.

The use of probiotic in chicken-broilers feeding

Biologically active feed additives of natural origin that do not hurt the body are increasingly used in poultry farming, making it possible to produce safe food products. It is known that probiotics are preparations of microbial origin that manifest their properties through the regulation of intestinal microflora. The primary mechanism of action of probiotics is to populate the gastrointestinal tract with strains of beneficial bacteria that displace opportunistic microflora from the intestinal biocenosis. The experiment aimed to establish the effect of probiotic feed additives on the productivity, slaughter performance, and meat quality of broiler chickens. Following the purpose of the research, a scientific and economic experiment was conducted on two similar groups of broiler chickens of the “Cobb-500” cross from one day to 42 days of age, with 20 heads in each group according to the experiment scheme. The experiment lasted 42 days. With the use of a feed additive in feeding broiler chickens of the 2nd group, the live weight increased by 11.9 % (Р ≤ 0.001) compared to the control group. It was found that under the influence of the supplement, the average daily growth in broiler chickens of the 2nd group was higher by 12.1 %, absolute by 12.2 % (Р ≤ 0.001) compared to control peers during the entire experiment period. In addition, in the 2nd group of broilers, feed consumption per 1 kg of growth is reduced by 8.9 % compared to the control. The use of a feed additive in the feeding of broiler chickens of the 2nd group increases the pre-slaughter live weight by 12.0 % (Р ≤ 0.001), the weight of an uncut carcass by 12.1 % (Р ≤ 0.001), half-cut carcass by 9.9 % (Р ≤ 0.01) and by 13.3 % (Р ≤ 0.001) relative to the control value. With the consumption of the investigated feed additive in broilers of the 2nd group, the level of total moisture in the pectoral muscles increased by 1.3 % (Р ≤ 0.05), and in the femoral muscles, the hygromoisture level was higher by 0.2 % (Р ≤ 0.05) and the amount of nitrogen by 0.2 % (Р ≤ 0.05), compared to the control group.

Effect of mineral feed additive on productivity of broiler chickens

Mineral elements play an essential role in the metabolic processes carried out in the animal body at the cellular level. They support homeostasis, acid-base balance, and osmotic pressure. Lack of mineral elements leads to disturbances in metabolic metabolism, reduced productivity, and increased morbidity in poultry. Therefore, the research aimed to establish the effect of selenium-containing feed additives on broiler chickens' live weight, gains, feed consumption, slaughter, and hematological indicators. Selenium – exchanges proteins, fats, and carbohydrates to regulate enzymatic and redox reactions. The introduction of selenium into animals' rations contributes to the normalization of metabolism, preventing the accumulation of toxic oxidation products and damage to the cell membrane. The experiment lasted 42 days. Two groups of Ross-308 cross-broiler chickens, 20 heads each, were selected for the experiment. In addition to compound feed, the second experimental group used a mineral feed additive at the rate of 100 g per 1 ton of compound feed. When broiler chickens were fed a mineral feed additive, live weight increased by 4.9 %, average daily weight gain by 4.8 %, and absolute weight gain by 5.0 %, relative to control counterparts. It was established that using a mineral feed additive in feeding broiler chickens of the 2nd group, the consumption of feed per 1 kg of growth decreased by 9.0 %, compared to control analogs. It was found that the pre-slaughter live weight of broiler chickens of the 2nd group increased by 5.0 %, the weight of non-carcass carcass by 5.6 %, half-carcass by 5.5 %, and carcass weight by 6.2 %, compared to the control value. In addition, under the influence of the studied feed additive, the mass of the pectoral muscles in broilers of the 2nd group increases by 16.0 % (Р ≤ 0.05) and thigh muscles by 36.0 % (Р ≤ 0.001) relative to control indicators. It was found that in the broilers of the 2nd group, under the influence of the additive, the slaughter yield of the thigh muscles increased by 29.4 % (Р ≤ 0.05) compared to the control group. It was established that under the action of the mineral supplement, the level of hemoglobin in broiler chickens of the 2nd group increased by 5.3 % (Р ≤ 0.05) relative to the control value.

Productivity and slaughter performance of pigs using a mineral feed additive

For the organization of pork production, it is necessary to create a strong fodder base that would provide the physiological needs of pigs in accordance with a reasonable level of productivity. The main method of growth stimulation and realization of the genetic endowments of animals is the use of biologically active feed additives in their feeding. The study of mineral nutrition of animals deserves special attention. Therefore, the aim of the research was to determine the influence of the mineral supplement “Mintrex Cu” on productivity and slaughter performance in pigs. Mineral feed supplement “Mintrex Cu” is a copper chelate of methionine hydroxy analog with a well-defined chemical structure, which contains 18 % copper and 79.5 % methionine activity. The protocol and procedures used in this study were ethically compliant with Directive 2010/63/EU of the European Parliament and of the Council on the Protection of Animals, as well as the Law of Ukraine “On the Protection of Animals from Cruelty”. The experiment lasted 55 days. 24 heads of large white pigs were selected for the experiment. Formed two similar groups of 12 goals each. During the formation of groups, live weight, growth, age, sex and breed were taken into account. Animals were kept in group pens of 12 heads, according to the number of experimental groups, in a typical piggery for raising young animals. A control group of pigs was fed compound feed that provided their nutritional needs. The experimental group additionally consumed the mineral supplement “Mintrex Cu” in a dose of 280 g/t of feed. It was found that the additional use of the mineral feed additive “Mintrex Cu” increases the live weight of pigs of the 2nd experimental group by 4.8 % (Р ˂ 0.05), compared to the control group. In addition, it was recorded that the preservation of pigs increased in the 2nd experimental group by 2.0 % against the control. The use of a mineral supplement in the feeding of pigs of the 2nd group, feed consumption per 1 kg of growth is reduced by 14.2 % compared to the control group. It was established that the pigs of the 2nd group, which consumed the mineral supplement “Mintrex Cu” had a higher pre-slaughter live weight by 5.6 % (Р ˂ 0.05) and slaughter weight by 6.5 % (Р ˂ 0.05) and carcass weight by 8.2 % (Р ˂ 0.05) compared to the control indicator.

Hematological indicators of bulls and their meat productivity depending on the structure of the ration

The article reflects the results of long-term scientific research conducted by the department of animal feeding and feed technology on fattening cattle. The task of the research was to study the specifics of the formation of meat productivity by the body of bulls of the Volyn meat breed, depending on the level of feeding, which, under the same type of ration, fully meets the animal's need for nutrients, in particular, in dry matter, available energy, the fractional composition of protein, carbohydrates, minerals and biologically active substances. The question of the organization of full-fledged nutrition of livestock of specialized meat breeds with the same type of feeding all year round using hay-type monoforage is relevant, especially in the practice of fattening young animals, with the aim of obtaining veal meat and young beef. This type of fodder according to the recipe proposed by us is produced at the “Pchany-Dеnkovich” farm. More complex fodder mixtures of three, four and five components have also been developed, based on the principle of field-made compound feed, which has received the name grain hay. Rations of this type do not require the use of concentrated feed when fattening livestock. This is exactly the approach reflected in the materials of the scientific and practical publication on the intensity of the functional growth processes of muscle tissue without excess fat. The data obtained in our research allow us to conclude that there is a direct relationship between the total protein content in muscle tissue and the nutritional qualities of the forage in the ration. Monofeed components such as grain of corn cobs of milk-wax maturity and soybean pods provide a relatively high protein content in the feed, which ensured high average daily gains in live weight with a limited amount of concentrates. The control slaughter of bulls at the end of the experiment showed that the average pre-slaughter live weight was at the level of 541–501 kg. The slaughter yield of the carcass had a direct dependence on the structure of the ration with a slight intergroup difference, which was within 0.8–1.2 % in relation to the first group, whose ration compensated the animals' need for energy and protein due to concentrates and was usually more expensive. Therefore, the replacement of part of the concentrates in terms of nutrition of the second and third groups does not lead to a significant negative impact on the morphological composition of the carcasses, which gives reason to assert the effectiveness of such rations. The conducted studies on fattening bulls of the Volyn beef breed allow us to state that the harvesting of monoforage (corn-soybean) of the hay type, the nutritional value of which is more than 0.5 fodder unit, which contains a sufficient amount of protein, carbohydrates, vitamins and mineral salts, ensures high average daily gains in live weight and has a positive effect on the quality indicators of young beef meat. The production of this type of fodder allows to produce 78.1–99.8 hundredweights of fodder unit from 1 ha of fodder area and 6.1–13.9 hundredweights of digestible protein and makes it possible to reduce the consumption of concentrated feed in the structure of the rations of fattening animals.

Efficiency of a food supplement containing Saccharomyces cerevisiae culture in the diet of broiler chickens

Currently, high productivity parameters in poultry farming are achievable only by maximum fulfillment of the poultry’s biological needs, because only healthy and highly productive birds can be the basis of the sphere’s profitability. All this is closely associated with the usage of feed additives of natural origin and effective methods of poultry farming, which provide high productivity and natural resistance of a bird’s body. In the experiment, we examined the effects of a probiotic feed additive on the productivity and slaughter parameters of the broiler chickens. Intake of the feed supplement by the experimental-group broiler chickens increased their live weight by 5% at the age of 28 days, 12% at the age of 35 days, and by 14% at the age of 42 days, compared with the control group. Using the tested probiotic feed supplement in the diet increased the mean daily (by 15.9%) and absolute increments (by 14.4% compared with the control group). Intake of the probiotic feed supplement by broiler chickens of the experimental group increased their pre-slaughter live weight by 14.2%, weight of non-processed carcasses by 15.5%, semi-processed carcass by 15.7% and processed carcass by 15.3%, compared with the parameters of the control group. In broilers of the experimental group, there were increases in the general weight of muscles (10.3%), namely the breast muscles (11.8%), muscles of thighs and lower legs (9.8%), and weight of the gizzard (by 6.5%), compared with the control group. Intake of the probiotic supplement by the experimental-group broiler chickens resulted in increases in width of the proventriculus (28.5%), length of the gizzard (16.3%) and width of the gizzard (29.7%), compared with the control group of animals. The probiotic feed supplement increased the length of the duodenum (by 7.6%) and the jejunum (by 4.5%) in the experimental-group broiler chickens, against the control. Therefore, feed supplements based on cheap culture Saccharomyces cerevisiae are promising, because they are able to enhance the effectiveness of poultry farming at relatively small costs.

Effect of dry extract from Saccharomyces cerevisiae culture with selenium-containing amino acids on the productivity and chemical composition of meat of broiler chickens

Introduction of biologically active supplements to the diet of poultry results in maximal use of nutrients and positively influences the live weight and slaughter parameters. This promotes rational and economical use of fodders and boosts the poultry productivity. We studied a mineral feed supplement – an organic selenium compound, which has a much greater bioavailability than inorganic sources of selenium. Selenomethionine is easily digested in the organism and effectively used for synthesis of proteins. Broiler chickens of the experimental group that had been consuming the selenoamino-acid feed additive had greater live weight at the age of 14–42 days, compared with the control. Intake of the mineral supplement by the broiler chickens in the experimental group increased their mean daily increment by 8.5% and the absolute increment by 8.6%, compared with the control peers. In the experimental group of broilers, the mineral supplement increased the pre-slaughter live weight by 8.4%, weight of intact carcass by 10.1%. Also, the weight of the semi-processed carcasses (i.e. those with removed intestines and cloaca, filled crop, oviduct and ovary (in female specimens) increased by 4.3%, and the weight of the processed carcasses (the internal organs and abdominal-cavity fat and esophagus of which were removed, without head, legs and wing metacarpals) increased by 8.0%, compared with the control group of broilers. In the experimental group, the feed supplement gave 13.7% rise in the weight of the breast muscles and 14.5% increase in the weight of the thigh muscles, compared with the control group. Intake of this supplement in the experimental group promoted 7.5% increase in the weight of the gizzard by and 9.2% increase in the weight of the duodenum, as compared with the control. Usage of the selenoamino-acid feed supplement increased the protein concentration in the breast muscles of the broiler chickens by 1.9%, compared with the control. Intake of the mineral supplement increased the amounts of dry matter and fat in the thigh muscles of the experimental group, compared with the control group. Therefore, adding dry yeast extract to diet of broilers together with selenium-containing amino acids is a promising method of increasing the effectiveness of poultry farming.

Evaluation of meat qualities of crossbred young pigs of different breeding

Relevance. To ensure the profitability of production, it is necessary to use certain schemes for crossing pigs of different breeds. Since the choice of the correct crossing scheme can significantly affect the final result. Crossbred animals, due to the effect of heterosis, are superior in productive qualities to the original maternal and paternal breeds. The paper presents an assessment of the meat qualities of local young pigs obtained as a result of industrial three-breed crossing.Methods. To implement the scientific and economic experience, three groups of sows of pairs-analogues of a large white breed from the company Hypor (KB Hypor) were formed. Sows of the 1st group were crossed with boars of the Landrace breed from PIC (Landrace Pic), the 2nd — with boars of the Landrace breed from Genesus Genetics (Landrace Genesus), the 3rd — with boars of the Landrace breed from Hypor (Landrace Hypor), as a result, two-breed crossbreeds (F1) were obtained. Further, the obtained crossbred sows (F1) of the 1st, 2nd and 3rd experimental groups were crossed with boars of the Duroc breed from Genesus Genetics, as a result, they received commercial young (F2).Results. The highest pre-slaughter live weight was obtained from animals of the 1st group (125.12 kg). This is more than in the 2nd and 3rd experimental groups, respectively, by 5.8% and 4.0%. Significantly, the highest slaughter weight was in the 1st group (93.51 kg), and the lowest — in the 2nd (87.8 kg). Most of the meat was obtained from animals of the 1st group — 62.85 kg (p ≤ 0.05). This is higher than in the 2nd and 3rd experimental groups, respectively, by 8.2% and 5.9%.

Meat productivity of bulls of the Simmental breed and crossbreeds with blood relationship (? Simmental + ? Aberdeen-Angus), (? Simmental + ? Kalmyk)

The aim of the study was to establish the characteristics of the meat productivity of steers obtained from crossing Simmental cows with Aberdeen-Angus and Kalmyk bulls, depending on the cultivation technology. Scientific and economic experiments were conducted in three farms of the Karachay-Cherkess Republic: LLC firm Hammer (experience 1); SEC PZ Zarya -1 (experience 2) LLC Yugagrohim (experience 3) in 2021-2022. For the entire period of cultivation in crossbreeds (? Simmental + ? Aberdeen-Angus) in the first experiment, the average daily increase was 711 g, 8.5 energy feed units were spent on 1 kg of increase, while the increase in Simmental bulls was 655 g per day, 10.4 EQ was spent on 1 kg of increase, or 22.35% more. The crossbreeds (? Simmental + ? Kalmyk) were closer to the bulls of the Simmental breed in terms of growth and payment of feed. In the first, second and third experiments, the crossbreeds (? Simmental + ? Aberdeen-Angus) outperformed purebred simmentals by: pre-slaughter live weight by 29.7 (P>0.999), 12.1 and 13.9 (P>0.99) kg; the mass of the paired carcass by -18.5, 8.9 and 8.6 kg (P>0.99 – 0.999); internal fat weight by – 3.1 (P>0.999), 0.6 and 2.4 (P>0.99) kg; slaughter weight by – 21.6, 9.5 and 10.2 kg (P>0.99–0.999); slaughter yield by -1,07,0,66 and 0.49 abs.%; half-carcass weight by 9.1, 4,5. and 4.5 kg (P>0.99–0.999); muscle mass by -6.13 (P>0.999), 3.0 (P>0.95) and 3.74 (P>0.99) kg; adipose tissue by–3.75 (P>0.99), 1.91 and 0.58 kg, respectively.

Raised in changing climatic conditions arid conditions of the Volga region

The author proved the high adaptive abilities of sheep of the Stavropol breed, indicators of meat productivity and meat quality, as well as the possibility of further breeding of this breed in arid conditions. The research was conducted in CJSC "New Life" of the Novouzensky district of the Saratov region. The object of research was purebred rams of the Stavropol breed of different intrabreed productivity types. It was found that sheep of wool and wool-meat types grew equally from birth to weaning from mothers, but at 7.5 months the wool-meat type had a live weight of 4.83% higher compared to wool. Morphobiochemical parameters in young animals of both groups were within acceptable norms, but a slight excess was found in the wool-meat type. Sheep of the wool-meat type were superior to wool in pre–slaughter live weight by 4.83%, the mass of the paired carcass – 9.22%, in slaughter yield - 1.73%. The young animals of the wool-meat type had more protein by 0.60%, the wool-fat by 0.70%, so their meat is more complete.

Meat Productivity of Kazakh and Tuva Horses

The research aims to study the meat productivity of Kazakh and Tuva horses in a comparative age aspect. The objects of the research are the local populations of horses of the Kazakh breed in the Republic of Kazakhstan and the Tuva native breed in the Republic of Tyva of the Russian Federation. All animals were clinically healthy. It has been established that in Kazakh foals, the pre-slaughter weight at 6 months of age was 195.5 kg, at 12 months 268.6 kg, 18 months 319.0 kg, 24 months 327.5 kg, 30 months 388.3 kg, and the Tuva breed 174-210-290-310 and 342 kg, respectively. The relative weight of the organs of the digestive tract from the pre-slaughter weight of animals in Kazakh colts of 6-month age is minimal, taking 6.4%, at 12 months 7.09%, 18 months 6.72%, 24 months 6.76% and 30 months 5.85%. The research results showed that in Kazakh colts, although the internal vital organs grow and develop in absolute terms with the age of the animals, in a comparative aspect with the pre-slaughter live weight, their percentage decreases. Thus, the liver of a 6-month old Kazakh colt weighs 4.0 kg, which is 2.0% of the pre-slaughter weight, at 12 months 5.5 kg (2.1%), at 18 months 5.7 kg (1.81%), at 24 months 5.8 kg (1.79%), and 30 months 5.8 kg (1.52%). A similar picture is observed for the lungs, heart, and kidneys. It was found that in Tuva colts from 6 to 24 months of age, the coefficient of meatiness varied from 6.0 to 6.3.

Slaughter qualities and by-product yield in Limousin bull calves of different genotypes

The study aimed to provide a comparative analysis of post- slaughter performance and by-product yield obtained from purebred Limousin bull calves of different genotypes. The purposes of the study were to fatten bull calves, offspring of mothers of different origin, as well as carcasses and by-products obtained as a result of their control slaughter. The bull calves were raised according to the technology of beef cattle breeding with elements of resource saving. The control slaughter of the bull calves was carried out when they reached the required meat condition at the age of 18 months. In the course of the research, it was established that the bull calves obtained from mothers of French selection significantly exceeded (p˂0.01) the peers obtained from mothers of Australian origin in live pre- slaughter weight of 34.6 kg (6.5%), in carcass weight of 30.8 kg (9.8%); in slaughter weight of 30,6 kg (9.4%). Bulls derived from local selection mothers had significantly (p˂0.05) higher slaughter weight by 16.3 kg (4.4%) compared to peers whose mothers were of Australian origin. Significant differences between groups in weight and yield of byproducts were not revealed; however, there was a tendency to increase the weight of organs in the groups of animals with high preslaughter live weight (bull calves of the first and third experimental groups). Based on the obtained data, it can be assumed that breeding of the ancestors of the studied animals for a long period of time under conditions of different breeding, housing and feeding technologies influences the meat qualities of carcasses obtained by their offspring, Limousin bull calves, which are descendants of mothers of different origin.

МОРФОЛОГИЧЕСКИЙ СОСТАВ И СООТНОШЕНИЕ ТКАНЕЙ В ТУШЕ БАРАНЧИКОВ РОМАНОВСКОЙ ПОРОДЫ И ЕЕ ПОМЕСЕЙ С ЭДИЛЬБАЕВСКОЙ ПОРОДОЙ

The article presents the results of crossing Romanov sheep with Edilbaev sheep in the production of young mutton. It was found that due to the eff ect of crossing, the crossbreeds of the fi rst generation (½ Romanovskaya × ½ edilbai) and the second generation (¼ Romanovskaya × ¾ edilbai) were distinguished by a higher yield of the edible part of the carcass, the meat content coeffi cient, the yield of carcass pulp per 1 kg of pre-slaughter live weight, a better ratio of edible and inedible parts and a muscle-fat ratio in compared with purebred youngsters of the Romanov breed.