Bulletin of Sumy National Agrarian University. The series: Livestock

PHYSIOLOGICAL FUNCTION OF ISOMALTOSE OLIGOMERIC AND ITS APPLICATION IN FEED INDUSTRY

Oleksandr Kyselov — 2025-03-14

The present review article highlights the results of modern research on the development and use of phytogenic additives in the feeding of farm animals and poultry. Particular attention is paid to the analysis of the effectiveness of phytogenic additives as an alternative to antibiotics aimed at improving animal health, increasing their productivity and improving the quality of meat raw materials. The materials of the article serve as a basis for an analytical synthesis of modern approaches to solving the problem of reducing the use of antibiotics in livestock and poultry farming, which is important for ensuring food safety and preserving ecological balance. Today, isomaltose oligosaccharide is a promising green feed additive that can replace antibiotics due to its unique biological properties. As a feed additive, isomaltulose can promote the growth of bifidobacteria in the intestinal tract, inhibit the growth of Escherichia coli, which, according to our research, has a positive effect on improving the functioning of the intestine and improving its internal bacterial environment, while improving animal health. Isomaltose also helps to strengthen the immune system of animals by stimulating the growth of beneficial microflora in the intestines. It supports the health of the digestive system, reducing the risk of developing infectious diseases. In addition, this additive is environmentally friendly and does not cause antibiotic resistance, making it safe for both animals and consumers of their products. In addition, the use of isomaltose is aimed at reducing the use of chemicals in livestock farming, ensuring improved product quality and safety for the end consumer. The introduction of isomaltose into livestock production is an important step towards the sustainable development of the poultry industry. The use of isomaltose as a feed additive in poultry production meets modern environmental standards and helps to improve product quality without harming the environment. This article also focuses on the physiological function of isomaltulose, its unique properties and prospects for use in the feed industry. The article discusses its impact on metabolism, its ability to provide animals with energy for a long time, and its role in maintaining a healthy intestinal microflora. Special emphasis is placed on the possibility of using isomaltulose as an effective ingredient for the creation of high-quality and safe feed that meets modern standards in animal husbandry.

ADAPTIVE CAPABILITIES OF HOLSTEIN COWS OF INTRODUCED ORIGIN AND THEIR OWN REPRODUCTION

Viktoriia Vechorka — 2025-03-14

In Ukrainian farms, it is constantly practiced to import livestock of Holstein animals of foreign selection, which motivates the expediency of studying their adaptability. The signs that characterize the milk productivity of cows of different genotypes were studied within two selection groups of the Holstein breed of Canadian selection – introduced and cows of their own generations. The assessment of Holsteins of Canadian breeding showed that their milk productivity is sufficient in new ecological, technological and feed conditions. Data from prim parous cows showed that they produced an average of 6,377 kg of milk, with a high fat (3.92%) and total fat (250.0 kg) content. Holstein cows gained weight during the first three lactations with a significant increase in the second compared to the first by 574 kg (Р<0.001) and in the third by 848 kg (Р<0.001). Starting from the fourth lactation (6.798 kg), the average milk yield of Canadian Holsteins began to decrease slightly, stabilizing at the same level from the fifth to the seventh with an average milk yield for the last one of 5.487 kg. Canadian Holsteins' hope for better lactation was 7557 kg. The fat content of the milk of first-born cows with variability in the total proportion of fat was 3.82-3.94%, and the yield of fat was 211.8–284.7 kg. The analysis of the selection situation based on the evaluation of the available stock of cows of own reproduction proved not only the preservation, but also the increase of milk productivity by them, surpassing similar characteristics of Holsteins brought to the farm from Canada. The first-born cows of their own reproduction were better than the introduced Holstein cows of the same age for milk yield with a difference of 280 kg (Р<0.01), and for higher lactation – by 432 kg (Р<0.01). According to the fat content, a narrowing of the phenotypic variability was observed in animals of own reproduction, which was within the limits of 3.81–3.84%. According to the level of coefficients of variation of the hopes of cows of their own reproduction according to the general information base, it depended on the year of calving, especially the first, by 14.3–44.2%. Almost at the same level, the variability of the coefficients of total milk fat yield (11.2–47.7%) in the general phenotypic variability of this trait indicates a significant influence of the year of calving. The fat content according to the obtained coefficients (7.6–21.4%) depended to a lesser extent on the influence of the year of calving. The introduced Holstein breed from Canada in new technological and ecological-feed conditions was characterized by high adaptive capacity, which is confirmed by the indicators of milk productivity of both the imported livestock and animals of their own reproduction.

DEPENDENCE OF BOAR CARCASS QUALITY AND ECONOMIC EFFICIENCY OF PORK PRODUCTION ON THEIR PRE-SLUTTER LIVE WEIGHT UNDER VARIOUS METHODS OF THEIR CASTRATION

Dmytro Zhdanov — 2025-03-14

The article studied the dependence of boar carcass quality at different pre-slaughter weights and castration methods and the economic efficiency of their rearing and slaughter. For this purpose, 200 boars obtained from F1 sows (♀BW × ♂L) and terminal boars of the sentient line RIS-337 of English origin were divided into two groups, 100 surgically castrated on the second day of their life. At the same time, the other 100 remained uncastrated until the use of immunocastration, which was carried out with the Improvac vaccine at the age of 112 and 140 days. During rearing and fattening, the animals were kept in standard industrial conditions in group barns of 50 animals, with a fully slotted floor and an automated feeding system, which was carried out 10-14 times a day with liquid feed mixtures in a ratio of dry to liquid fractions of 1:2.7–3.0. When the experimental animals reached an average live weight of 110 kg, they were individually weighed and divided into three groups with pre-slaughter live weights of 100, 110, and 120 kg, with further slaughter at the Globinsky Meat Processing Plant LLC to determine the morphological composition of carcasses and large-cut semi-finished products. It was found that immunocastrated animals had a higher percentage of lean meat in the carcass and a reduced proportion of adipose tissue, which can be beneficial for meat producers who focus on the lean pork market. It was proved that the highest economic efficiency in fattening and slaughtering boars was achieved at a pre-slaughter live weight of 120 kg, regardless of the castration method, and the total profit from immunocastrated animals was higher due to lower feed consumption and optimal meat yield, which led to higher profit from its sale. It was found that in the shoulder-blade part of the carcass, surgically castrated pigs showed a higher weight and proportion of bones from the neck and skin on the back compared to immunocastrated counterparts but were inferior to the latter in terms of weight and proportion of single-cut pork from the neck, single-cut pork from the shoulder blade and shoulder bones. In the dorsal-lumbar part of the carcass, boars of both castration methods differed only in the higher weight and content of the beam and brisket bones in immunocastrated males compared to surgically castrated peers. The predominance of weight and content of most meat cuts in three parts of the carcass of 120 kg boars relative to lighter 100 and 110 kg analogs under both castration methods was proved. It was found that at slaughter with a live weight of 100 kg, immunocastration provided 140 UAH more profit than surgical castration. It was determined that the most appropriate income from the sale of large-cut semi-finished products is slaughter at a live weight of 120 kg, regardless of the castration method. It was determined that the average income was higher in immunocastrated boars, which indicates their potential economic advantage in industrial pig production. The use of immunocastration increases production profitability, especially in the case of lean pork sales. Further research is needed on the effect of castration on the long-term preservation of meat quality and consumer properties of products.

THE CONTENT OF PB AND CD IN FEED AND THEIR TRANSITION INTO MILK AT DIFFERENT PRODUCTIVITY OF COWS

Svitlana Kovalova — 2025-03-14

As a result of hostilities in Ukraine, the accident at the Chernobyl nuclear power plant and other man-made disturbances, a growing threat to the health of animals and people has arisen. An important role in this process belongs to the anthropogenic entry into the biosphere of heavy metals, which are highly toxic, have the ability to accumulate in the body of animals and people, and cause harmful effects even in low concentrations. Monitoring of feed and milk contamination with heavy metals (Pb and Cd) was carried out in agricultural enterprises of Zhytomyr region with different levels of cow productivity: PAF "Yerchyki" with a daily milk yield of 20–22 kg of milk and DPDG "Nova Peremoga" with a daily milk yield of 13–14 kg of milk. The type of animal feeding in both farms is silage-hay-hay-concentrate. Preparation of selected samples of feed and cow milk for determination of heavy metals in their composition was carried out by the method of dry mineralization according to DSTU 7670:2014, analysis – on an atomic absorption spectrophotometer "Kvant-2A". The results of the conducted studies on the content of Pb and Cd in average samples of fodder crops clearly indicate the presence of significant fluctuations in heavy metals within farms and feeds. High concentrations of Pb and Cd were found in roughage and sunflower cake and meal – 1.238–3.639 mg/kg and 0.199–0.404 mg/kg and 1.904–2.464 mg/kg and 0.408–0.908 mg/kg, respectively. In addition, alfalfa hay and sunflower cake and meal exceeded the MPC for Cd content by 1.35–3.03 times. Feeds prepared at the Yerchiky Agricultural Farm compared to the Nova Peremoga Agricultural Farm contain significantly higher amounts of Pb and Cd: in alfalfa hay – 2.42 times and 1.68 times, in barley straw – 1.23 and 1.21, in corn silage – 1.61 and 2.23, in alfalfa haylage – 1.24 and 1.56, in sunflower meal and meal – 1.29 times and 2.22 times, respectively. According to the results of milk analysis, in both farms, the regulatory requirements for Pb content were exceeded by 1.02–1.86 times and Cd – by 1.30 times (Yerchiky Agricultural Farm). The highest rates of accumulation and transfer of heavy metals from ration feed to milk were observed in the farm with higher cow productivity.

THE DEPENDENCE OF THE REALIZATION OF THE GENETIC POTENTIAL OF PIGS ON THE CONDITIONS OF CARE AND FEEDING

Olha Korzh — 2025-03-14

Today's pig farming is a high-tech hobby, where the success of breeding largely lies in the diversity of minds, reducing the genetic potential of animals. The productive capacity of pigs is determined not only by their sluggishness, but also by adhering to technological standards such as balanced yearning, microclimate and veterinary prevention. Lack of attention to these minds can lead to a decrease in productivity, loss of life quality and stress syndromes in animals, which is negatively associated with end products. Particular attention must be paid to the specific needs of genotypes that have high productive potential and are also sensitive to external factors. It has been found that minor changes in optimal technological parameters in which the breed is formed or a synthetic line can significantly reduce the level of productivity. For example, current maternal lines of sows demonstrate high fertility and efficiency of feed conversion, and farmed pig farms will not always provide realizing this potential. The article is devoted to the influence of genetic and technological factors on the productivity of current breeds and hybrids of pigs. The delay in the implementation of the recession potential of animals in the minds of maturation, yearling, veterinary prevention and microclimate is analyzed. It is understood that minimal adherence to technological standards can lead to a decrease in productivity. The role of modern methods of genetic selection, genomic selection and DNA screening, which allow increasing the efficiency of breeding robots, is closely examined. The use of such technologies by leading international companies is being instituted. The authors appreciate the importance of adapting brains to the specific characteristics of new genotypes, maintaining temperature conditions, feeding programs and veterinary control. It is clear that the successful development of natural genetics in pig breeding requires an integrated approach, which includes technological adaptation of all genetic processes. Unsystematic changes or neglect of necessary factors can lead to the loss of productive performance and economic savings. Therefore, highly productive pig farming will require a comprehensive approach, which includes genetic monitoring, optimization of mental health, proper yearling management and veterinary care. The transition to new genetics is accompanied by the adaptation of the entire reproductive system to effectively unlock the potential of animals. A systematic approach allows us to achieve stable productivity and economic profitability in livestock farming.

THE EFFECT OF MILKING FREQUENCY ON THE PERFORMANCE, HEALTH AND METABOLIC STATUS OF DAIRY COWS

Oleksandr Ovcharenko — 2025-03-14

This review article examines lactation management in dairy farming, focusing on milking frequency and its impact on the performance, health and metabolic status of dairy cows. Lactation is a key part of milk production, ensuring the profitability of dairy farms. Over the decades, advances in milking technology – from manual to robotic systems – have transformed the industry, increasing milk yields and milk quality. However, achieving a balance between maximizing milk production and maintaining cow health remains a significant challenge, as metabolic disorders such as ketosis often arise from the stress associated with lactation. In modern dairy complexes and farms, cows are often milked three times a day, but current research suggests that increasing or decreasing milking frequency can have a significant impact on milk yield, quality and cow health. Increasing milking intervals significantly affects milk production, metabolic processes and dairy cow health. To achieve optimal performance and maintain cow health, it is necessary to carefully control milking frequency and consider the length of milking intervals, especially in automated milking systems. Insufficient adaptation of dairy cows to the period of negative energy balance during the transition from late dry period to early lactation significantly affects animal health and performance. Reducing milking frequency in early lactation can positively affect the metabolic status of cows, in particular, blood calcium levels. At the same time, these cows had increased levels of somatic cells in milk and cortisol, which indicates reduced udder health and increased stress. Reduced mobilization of body reserves and improved immune response during single milking indicate benefits for energy balance, but possible risks for udder health. The article reviews modern milking technologies, their application and impact on the metabolic health of cows, focusing on the importance of monitoring systems for disease prevention. The article offers recommendations on optimal milking strategies and preventive measures to maintain animal health and improve dairy farm efficiency.

TRENDS IN THE DEVELOPMENT OF GLOBAL, EUROPEAN, AND UKRAINIAN PIG FARMING

Mykola Povod — 2025-03-14

This article aims to analyze the state of global, European, and Ukrainian pig farming over recent years and its role in global and national meat production, as well as in ensuring the meat supply for populations in specific regions of the world. The study examines trends in pig farming development at global, European, and Ukrainian levels, focusing on key factors affecting the efficiency of this industry. Special attention is paid to changes in pork production volumes and their significance in ensuring food security. The study is based on statistical data from FAO, European and Ukrainian statistical organizations, the analytical department of the Association of Pig Farmers of Ukraine, as well as scientific works by experts in pig farming. Methods of synthesis, analysis, and comparison are applied to assess the development of pig farming on global, European, and Ukrainian platforms. Global pork production showed growth, reaching nearly 108 million tons in 2021, increasing to 110.7 million tons in 2022, 115.2 million tons in 2023, but declining in 2024 to 114.2 million tons in slaughter weight. From 2022 to 2024, global pork production displayed mixed trends depending on the region. While production in China and Europe declined due to internal and economic factors, countries in the Americas and certain Asian states expanded their production capacity, driven by domestic and external demand. In Asia, pig farming during 2022–2024 faced both positive and negative factors, including economic uncertainty, reduced production volumes, and declining livestock numbers in China. However, Vietnam demonstrated growth, highlighting the region's significant potential in pig farming. Asia remains a strategically important market for global pork exporters, with demand for pork remaining high despite slight declines in certain areas. In the EU, pig farming is experiencing a crisis characterized by reduced production, declining competitiveness, and economic challenges. The lack of significant growth in domestic demand, reduced export opportunities, and high production costs pose serious challenges to the industry's future development. In the Americas, pig farming demonstrated stability and positive dynamics from 2022 to 2024 in countries like the United States, Mexico, and Brazil. These countries increased both production volumes and export capacities due to competitiveness and strong international demand. Despite a production decline in Canada, its export levels remain high. The continent's pig farming industry has significant potential for further growth, particularly given the stable demand in Asian markets. In Ukraine, pig farming between 2022 and 2024 faced considerable difficulties due to military actions, economic instability, and declining livestock numbers. However, there is a trend toward the concentration of production on large industrial farms, which may contribute to the stabilization of the industry in the future. For further development, it is necessary to focus on supporting producers, improving production efficiency, and ensuring food security.

EFFECTIVENESS OF THE APPLICATION OF OPTIONS FOR PRE-START FEEDING OF PIGLETS

Viacheslav Popsui — 2025-03-14

The research presented in this work is aimed at testing the influence of various types of pre-start feed on the growth, development and preservation of piglets in the nursery and post-weaning periods. The main boundary factor in growing piglets is the natural biological boundary of the lactation productivity of sows, which leads to a shortage of live milk in siblings and the need for early introduction of supplementary feed. The method of work is to assess the effectiveness of various prestarter feeds in one-year-old piglets and analyze their impact on productivity indicators. Research methods included experimental assessment of growth performance of piglets, saving rate, milk production of sows and feed efficiency. The investigation was carried out by the government on the basis of a scientific-government experiment, in which 12 sows and their offspring were tested. The piglets were divided into three groups, the skin of which received different options of pre-start feed: TM Best Mix 8393, Laktofit-Porco 1 (light) and Laktofit-Porco 2 (dark). The average weight gain, live weight of piglets at 35, 60 and 100 days, as well as the rate of their saving were analyzed. The results showed that until the 21st day, no statistically significant differences between the groups were recorded. However, the piglets that received Lactofit-Porco 1 showed better indicators of life expectancy, comparable to other groups. At the same time, piglets that were fed Lactofit-Porco 2 had slightly lower average growth rates. The highest indicators of productivity were recorded in the group that fed Best Mix 8393, the fragments of this compound feed better satisfied the consumption of piglets in older piglets after a decrease in the supply of milk from the mother. Until the 60th day of age, piglets from the first group have a low live weight of 4-6% equal to that of other groups, and their average weight gain remained consistently high. The discussed results indicate that the use of high-quality compound feeds allows minimizing feed stress in piglets after weaning, which has a positive impact on their growth and savings. Piglets that have been fed the Best Mix 8393 pre-starter are less susceptible to feed stress, adapting better to changing the diet and finding more effective feed intake. Recently, a cost-effective analysis demonstrated that the use of mixed feed from local breeding was less effective, resulting in additional costs of 2.08–2.35 mental units ($) per pig after separation from the world of five years. Thus, the results of the study confirm that clear pre-starter feed is an important factor in ensuring optimal growth of piglets and increasing the economic efficiency of pig farming. The use of pre-starter feeds, divided according to current technological standards, allows for the preservation of piglets, promotes their rapid adaptation and minimizes the negative effects of technological stress. The findings may be useful for the development of effective strategies for yearling piglets in industry minds.

MODELING OF THE COMPONENTS OF LIVE WEIGHT CURVES OF HENS

Viktor Khvostyk — 2025-03-14

The article presents the results of descriptive modeling of the polygenically determined quantitative trait «live weight» on a wide genetic material of chickens of different genotypes, obtained during an experiment to study the effectiveness of crossing imported meat crosses with meat-and-egg females of domestic selection. In general, it can be noted that the mathematical models used by B. Gompertz, T. Bridges, F. Richards made it possible to fairly adequately describe the dynamics of increasing the live weight of chickens of different genotypes. The average percentage of deviations of the actual values of live weight from the theoretically calculated ones according to the B. Gompertz model ranged within 1.73–8.36%. The smallest discrepancies were determined in chickens of the improved subpopulation “K-5», the largest ones in birds F11 of the subpopulation “K». With the smallest discrepancy from the actually determined values, the B. Gompertz model described the live weight at the end of chicken rearing – at 10 weeks. When using the T. Bridges model, in the vast majority of the studied groups of chickens, a significant underestimation of live weight indicators at the 2nd week of life was noted – by 11.17–24.76% compared to the actual ones. Also, this model in all groups of poultry slightly overestimated the live weight at the 8th week (by 3.95–15.70%). In general, the average percentage of deviation between the actually obtained live weight indicators and the theoretically calculated ones was 1.59–8.34%. In chickens of the synthetic population «K-5», the maximum accuracy of the description of the dynamics of the live weight of chickens in early ontogenesis was obtained. The model of F. Richards, similar to the model of T. Bridges, in most groups underestimated the values of live weight at the 2nd week. This is especially clearly observed in meat-egg chickens F11 and offspring F2 – the deviations of empirical values from the actual ones are significant (13.67–20.81%). Also, the F. Richards model overestimated the live weight at the 8th week of chicken life by 3.91–13.15%. Like the previous two models, this model described with high accuracy the dynamics of the live weight of chickens during 10 weeks of growing in the synthetic population «K-5». The discrepancies between the actual and theoretically determined by the model live weight values are minimal – only 1.78%.

FACTORS INFLUENCING THE SIGNS OF LONGEVITY DAIRY COWS – REVIEW

Leontii Khmelnychyi — 2025-03-14

The article presents an in-depth analysis of the results of research by domestic and foreign scientists, conducted in the direction of studying problematic issues related to the influence of genotypic and paratypic factors on the traits of the duration of productive use and lifetime productivity of dairy cows. Genetic factors influencing longevity traits (breeding method, line, bull-sires, heredity by improving breed, degree of kinship, heritability, correlative variability) and paratypic (productivity, age of first calving, service period) were considered. World practice shows that increasing the genetic potential of dairy cattle productivity accompanied by negative consequences associated with a simultaneous decrease in reproduction characteristics, deterioration of udder and limb health, which leads to an increase in premature culling and a reduction in the traits of cows’ longevity. An important genetic factor, which, according to numerous studies, has an effect on longevity traits of dairy cows, is linear breeding, because of which successful combinations of linear and interlineal selection were used. The strength of line influence on life expectancy indicators, productive use, lactation and number of lactations during life in cows of Ukrainian Red-and-White dairy breed was 16.9–17.7%, and on the lifetime milk yield and milk fat amount in animals of Holstein breed – 18.6–22.4%. About the influence of bull-sires heredity and the types of parental pairs’ selection on the lifetime productivity of cows in different breeds reported by studies of domestic and foreign authors. A particularly important factor is inclusion of longevity traits in the selection index for assessing sires based on the quality of their offspring. The established existence of a positive correlation between the milk yield of the first lactation and the traits of longevity indicates the implementation, with the appropriate measure of efficiency, of effective indirect selection based on indirect predictive traits of first-born cows with the aim of selective improvement of longevity traits of the dairy cows. Most studies examining the effect of the age of first calving on longevity indicators report that too early (under 21 months) and late (over 29 months) calvings mostly lead to a reduction in both the duration of productive use and a decrease in the lifetime productivity of animals. According to the evaluation of cows of Ukrainian dairy breeds and the world in terms of reproductive capacity, it was established that the duration of service period significantly exceeds the optimal level in 80 days. With the growth of service period, indicators of longevity decrease with the strength of influence on life expectancy, productive use and lactation of cows by 12.5–36.5%, on lifetime productivity – 9.7–34.6, on milk yield per day of productive life use and lactation – 11.3–35.9%. The positive correlations between linear traits of the conformation and the functional longevity of cows from various breeds revealed in numerous studies indicate that they are good indirect predictors of the duration of productive life, and the degree of their heritability ensures effective selection in the direction of dairy type.

EFFECTIVENESS OF THE APPLICATION OF INTRA- AND INTERLINE SELECTION IN A HIGHLY PRODUCTIVE HERD OF CATTLE

Leontii Khmelnychyi — 2025-03-14

A study was conducted in the herd of breeding black and spotted dairy cattle of Chereshenki LLC to study the influence of heredity of breeder bulls under different variants of line selection. It was established that 70.3% of the brood stock was obtained due to the crossing of lines with higher productivity in individual variants than with linear breeding. Breeding bulls on the paternal and maternal lines of the P.F.A.Chief 1427381 line were used most intensively in the herd. According to the data of the first lactation, the greatest hope of cows was found in the Chif x Besna cross (9140 kg), which is significantly higher compared to the inline breeding of this line with a difference of 587 kg (Р<0.01). The superiority of first-born cows from crossing Chief x J. Rabies over representatives obtained from other crossings ranged from 343 (Chifa x Marshall) to 1448 kg (Chifa x Morello). The second in number of used breeding bulls and the offspring obtained from them is the sire line Eleveyshna 1491007 with all variants of crosses with maternal lines. The low level of variability of milk yield of first-born cows in the range of 7959–8991 kg indicates that Eleveyshna bulls have a high combining ability for all selection options. The first-born cows obtained from the Eleveyshna x Besna line cross are characterized by higher yield, fat content, and yield of milk fat and protein with indicators of 8,991 kg, respectively; 3.80% 341.7 and 291.3 kg. The Starbuck 352790 line is the third in number of pedigree bulls and offspring used in breeding. The progeny of Bogay bulls of the Starbuck line of inline selection with milk yield for the first lactation (8112 kg) indicates a sufficiently high potential of their breeding value. But the best in this respect were the daughters of inter-row cross Starbak x Elevishna (8285 kg). Breeding within the Starbuck line and interlineal crossings with maternal lines proved to be quite successful, as evidenced by the level of productivity of first-born cows obtained from combinations of these variants (7881–8285 kg). The significant variability of signs of milk productivity of cows depending on selection options indicates the feasibility of monitoring linear breeding in the selection process of improving the productivity of dairy cattle, as a result of which the best options can be determined.

PREDICTION OF COW MILK PRODUCTIVITY

Oleksandr Chernenko — 2025-03-14

The paper presents the research results of the prenatal period duration with the purpose to predict early milk productivity of the Ukrainian Red Dairy Breed cows. According to the individual offspring number, the length of the cow prenatal period of ontogenesis was calculated. For this, the date of fertile insemination of the mother and the date of calving were used. The animals were divided into three groups. The principle of group formation was used (x±0.67SD). Animals which had a prenatal period of ontogenesis shorter than the specified range were assigned to the group of a shortened period (group I), and those which exceeded this range – to the group of an extended period (group III), the rest – to the average group (II group). The duration of prenatal development was in the range from 270 to 276 days in the I group of cows, in the II group of cows it was from 277 to 283 days, in the III group of cows – from 284 to 290 days. The hypothesis that different somatic and functional precociousness of heifers can be detected already in the early ontogeny was the main idea of the research, and it was confirmed experimentally. This can influence the formation of their subsequent milk productivity, and therefore can be considered as a predictive marker. In the I group of cows, compared to the III group of peers, the milk yield during 305 days of the third lactation was higher by 650 kg of milk, milk fat was higher by 29.0 kg and milk protein – by 22.0 kg. Animals from the II group took an intermediate position, they differed significantly from peers from the III group in milk fat (P<0.05). The difference between the groups in terms of the component composition of milk was not reliable. The correlation between the indicators of the prenatal period duration and milk yield, milk fat and milk protein was inverse and reliable in the range from –0.326 to –0.357. The group-forming factor had the influence on the specified characteristics in the range of 22.1–28.7% at P<0.01. The influence of the prenatal period duration on the fat content and milk protein is insignificant and was in the range of 1.5–2.9% for P>0.05. Thus, it was established that the length of the prenatal period affects the level of milk yield, milk fat and milk protein and it can be a prognostic marker at an early age. Other things being equal, heifers with a shortened and average prenatal period and a live weight at birth within the limits of permissible deviations, that is, developed normally, should be selected for herd repair.

STUDY OF THE INFLUENCE OF THE CSN3 GENE GENOTYPE ON THE QUALITY CHARACTERISTICS OF COW MILK

Tetiana Cherniavska — 2025-03-14

Recently, scientists have emphasized the promising direction of using marker-associated selection measures in practical breeding work. In their opinion, this allows for the selection of animals based on their genotype. One of the important factors in the use of marker-associated selection in dairy cattle breeding is considered to be a significant acceleration of the selection effect. Scientific research on the influence of the kappa-casein gene (CSN3) on the indicators of milk productivity of cows of the Ukrainian black-and-white dairy breed was carried out on the basis of a breeding plant for breeding animals of this breed. The breeding plant belongs to the State Enterprise "Research Farm of the Institute of Agriculture of the North-East of the National Academy of Agrarian Sciences of Ukraine", located in the Sumy district of the Sumy region. The polymorphism of the kappa-casein gene was studied in the genetic laboratory of the Institute of Physiology named after. Bogomolets NAS using molecular biological analysis of allele recognition by real-time polymerase chain reaction (PCR) according to generally accepted methods. Milk productivity was assessed by monthly control milkings with milk sampling. A counter – indicator IU-1 was used to sample milk. The content of milk components was determined in the laboratory of the Institute of Animal Husbandry of the NAAS by infrared photometry using equipment from Bentley Instruments Corporation (USA). Among the studied animals, animals of three genotypes were identified: AA, AB, BB. Depending on the genotype according to the studied gene, there is a differentiation in the content of the main components of milk in favor of animals with the homozygous BB genotype. Both first-born and full-term animals with the homozygous BB genotype had a higher fat and protein content in milk. A statistically significant difference was established between them and animals with other genotypes (AA and AB). Accordingly, animals with the BB genotype also had an advantage in terms of dry matter content. There is no effect of genotype on the physical parameters of milk.

INFLUENCE OF PRE-INCUBATION STORAGE CONDITIONS AND CALIBRATION OF EGGS ON DIFFERENTIAL MORTALITY OF EMBRYOS OF DIFFERENT SEX

Oleksandr Chekh — 2025-03-14

The article highlights the importance of autosex poultry as a model object for scientific research due to its unique genetic and physiological characteristics. In particular, the issues of differential sex mortality are analyzed, which is an important aspect of studying the patterns of development of organisms. Poultry, especially chickens, are widely used as a model for analyzing the influence of external factors on ontogenesis. This applies to aspects such as sex ratio and embryo viability, which are key for fundamental biology and practical application in poultry farming. The study analyzed the sex ratio and mortality of chicken embryos under different conditions of pre-incubation storage and incubation of eggs. For this purpose, anatomical, Japanese, color-sex and federsex methods of sex determination were used, which ensured high accuracy of the results obtained. The studies covered a wide range of chicken breeds and hybrids, which made it possible to draw conclusions about the specifics of differential sex mortality in different genetic groups. The study analyzed the sex ratio of chicks depending on egg storage conditions, incubation regime and weight calibration. Under optimal incubation conditions, a secondary sex ratio close to 1:1 was confirmed. In seven batches of day-old chicks, the proportion of females was 49.71–53.49%, with an average value of 51.26%. Long-term storage of eggs (8–15 days) caused an increase in embryonic mortality (up to 28.1%) and the predominant death of male embryos, which led to a significant shift in the sex ratio in favor of females (61.7%). In contrast, short-term storage (1–7 days) did not affect the incubation indicators and ensured the expected equality of the sexes. The study of egg weight revealed that medium-weight eggs (group M0) provide the highest survival of embryos with an equal sex ratio. In small eggs (M-), the predominant death of male embryos was observed, while in large (M+) females died more often. Of the day-old chicks obtained from M- eggs, the proportion of females was 53.74–54.60%, and from M+ eggs, the proportion of males increased to 53.86–55.49%. Increased survival of embryos in the modal class of eggs (M0) is associated with their higher biochemical heterogeneity of protein proteins, which confirms the theory of genetic homeostasis. It was found that males are more sensitive to stress factors, which confirms the differential mortality of the sexes. The results obtained are consistent with the theory of bisexual evolution of V. A. Geodakyan. According to this concept, differential mortality of the sexes is an adaptive mechanism that allows the population to better adapt to stressful conditions. The study confirmed that under stress conditions caused by changes in egg storage or incubation conditions, male embryos die more often than female ones. This phenomenon was observed both in the embryonic and postnatal periods of development. Thus, the results of the work not only confirm the adaptive nature of differential mortality of the sexes, but also open new prospects for further study of the genetic and biochemical mechanisms that determine the development of embryos in different conditions. They are of great importance for optimizing breeding, incubation and reproductive management technologies in poultry farming.