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Gene expression at the phenotypic level varies due to a number of influences from the environment in which the animals are reared. Ignoring this reality or due to insufficient knowledge, farmers are often disappointed when choosing a population of sheep when they do not get the production results that the breed achieves where they bought it. The investigation of the reproductive and production characteristics of parent herds of Sjenica sheep was conducted on four farms. In the research, it included a total of 921 lambs and 474 sheep. The influence of sheep body weight on the weight of lambs at birth within a farm was analyzed. Based on the research conducted on the sheep population and after the obtained and processed data, we can state the following: certain differences were found in the fertility of sheep depending on the farm and body weight. We also perceived that certain differences in the body weight of the lambs are evident depending on the weight group of the sheep and the farm where the sheep were raised. All of the above leads us to the general conclusion that management is extremely important in sheep farming. If the selection of the breeding population is carried out correctly and adequate measures of keeping, nutrition and reproduction are applied, success is guaranteed.

Lipska sheep is an autochthonous Serbian population from the group of Pramenka (Zapfel) sheep, bred in the area around Smederevo, Požarevac and Mladenovac. The average weight of male animals (BW) is 95 kg and 62 kg of female animals. Other measurements of female animals are: wither height (WH) 74 cm, body length (BL) 78 cm, chest width (CW) 23 cm, chest depth (CD) 40 cm and hearth girth (HG) 91 cm. In the last sixty years, adult female animals gained in average ten kilograms of weight. Other linear measures also increased. The increase is a consequence of better animal management, especially improved diet. Since the reduction of the size of the population, larger animals have dominated, which probably caused the change in the genetic constitution of the breed. Female animals of Lipska sheep are higher compared to the animals of other fifteen Pramenka breeds with the exception of Istrian sheep. The area from which Lipska sheep originates has better soil and richer vegetation compared to the areas of other Pramenka breeds. Partial correlations corrected for weight between individual linear measures were positive, with values between 0.196 and 0.814. Most correlations range between 0.30 and 0.55. Body measurements were studied with ANOVA on females only. The effect of flock influenced all linear measures with the exception of CW, whereas the age of animals had no effect on BL, CW and CD. The increase of individual linear measures was 0.5 to 2.1 mm per kg of BW. The increase of most body measurements from the first to the fifth year was statistically significant (P

The research included a total of 921 lambs, 474 ewes and 8 sjenicke sheep rams from 4 different farms. The aim of the research was to examine the influence of the farm, cultivation technology and the influence of rams within the farm on production indicators. Statistical analysis showed that the body weight of lambs at birth ranged from 3.37 to 4.03 kg (average 3.68 kg), at 30 days from 11.51 to 12.41 kg (average 12.07 kg) and from 90 days from 27.82 to 29 kg (average 28.65 kg). A statistically highly significant influence of the farm was determined (P

The current study aimed to examine the percentage changes of viability sperm and the activity of the enzymes LDH, ALP, GOT / AST, GPT / ALT in the sperm plasma of Lacaune rams, before and after cryopreservation. For this purpose, five rams were examined, and two ejaculates were obtained from each ram. Ejaculates are collected by the method of artificial vagina, during the insemination campaign. All ejaculates were diluted with a 6AG extender and frozen by the Cassou's sequin method. Sperm viability was determined by eosin and nigrosine smears, and enzyme activity was examined spectrophotometrically. As a result, the percentage of vital sperm after cryopreservation decreased by 15% (P ≤ 0.001). The freezing and thawing process also reduced the activity of the enzymes LDH, ALP, GOT / AST and GPT / ALP. In conclusion, the observed enzymes, in relation to sperm vitality, could be used as indicators to optimize the protocols for cryopreservation of ram's sperm.

The Simmental breed of cattle is mostly reared in the central part of the Republic of Serbia, where it makes up about 80% of all breeds. In areas of more intensive cattle production, populations of cattle with pronounced milk yield are reared. In more extensive, as well as hilly and mountainous areas, somewhat less productive animals are raised. The main goal of this study was to examine the variability of genetic correlations of milk and fertility traits on the farms of individual agricultural producers using modern methods, depending on the breeding area, i.e. the region in which they are bred and reared. This study included 2589 controlled Simmental heifers, with lactations concluded during one year. All first calving heifers were housed and reared on agricultural family farms in the area of Central Serbia. The paper examines genetic correlations between the following traits of milk yield and fertility: duration of lactation, milk yield in standard lactation, milk fat content in standard lactation, milk fat yield in standard lactation, yield of 4% FCM in standard lactation, age at first calving, duration of service period. The results of the study of genetic correlations were obtained using mixed LSMLMW models (Harvey 1990). The examined genetic correlations of milk yield and fertility traits in Simmental cows showed pronounced variability depending on the breeding area where the cows are reared.

The strategy of conservation of endangered sheep populations implies morphological and genetic characterization, as basic preconditions for their conservation. The aim of this study was to determine the morphometric characteristics, their correlations and the index of physical development of Pirot pramenka, which has the status of the most endangered population in Serbia. The measuring was performed on 30 sheep, aged 3 years, reared in the area of Stara Planina. The descriptive statistical procedure was performed using the statistical package Statistica (version 8). The average height at the withers was 56.31 cm, body length 62.93 cm, chest width 18.37 cm, chest depth 25.96 cm, chest circumference 77.59 cm, shin circumference 6.70 cm. The strongest and significantly positive correlation (P

DNA analysis can have great practical application in the management and successful operation of the farm. The application of DNA technology is becoming a tremendous challenge for farm breeding of domestic animals. In recent years, traditional selection methods have been supplement by the results of molecular analysis of the genome. Determining the genetic distance of sheep and goat breeds had practical and multiple significance. Microsatellites are used widely in the selection, and genomic selection is becoming an increasing challenge for breeders. The development of SNP chips brings an immense advanced for rapid and comprehensive analysis of the genome, which is of great importance for the successful selection and Genomic selection in sheep concentrated on all aspects of genetic and production directions. However, it should be noted that genomic selections in sheep breeding, and especially in goat breeding, take place at a slower pace compared to cattle breeding.

Considering the fact that sheep production has an important role in agriculture of Serbia, lamb performance is essential. Objective of the study was to investigate effect of year, lambing season, sex and birth type on growth performances in lambs of MIS breed. Animal data (birth date, birth type, sex, birth weight -BW0, body weight after 30 days - BW30 and body weight after 60 days - BW60) are gained from control of productive parameters maintained from 2011 to 2020. Research was conducted on the sample of 1592 lambs. Average daily gain from birth to 30 days (ADG1), from 30 to 60 days (ADG2), and from birth until 60 days (ADG3), were calculated and included in analysis. Calendar year was divided in four seasons, each season consists from 3 months: winter, spring, summer and autumn. Average body weights (± standard deviation) at birth, after 30 and 60 days were 4.41 kg (± 0.99), 14.11 kg (± 2.80), 24.05 kg (± 3.86), respectively. Average daily gains were 319.87 g (± 74.97), 329.84 g (± 70.90) and 324.99 g (± 55.48) for ADG1, ADG2 and ADG3, respectively. Lambing type and sex of the lambs affected all of the observed traits very significantly (p < 0.01). Lambing year had very significant effect (p < 0.01) on BW30, on ADG1 and ADG2, while lambing season significantly (p < 0.05) affected BW60, ADG2 and ADG3.Based on the results it can be concluded that birth type and sex had strongest effects in early productive parameters of lambs.

The aim of the study was to determine whether the bacteria from the environment and from the mucous membrane of the boar prepuce have antimicrobial resistance and whether the result obtained is similar/same to the bacteria that can be found in native boar semen. The study addresses the problem of the presence of primarily resistant bacterial strains in the boar sperm, which, due to their reduced sensitivity, cannot be suppressed by antibiotics used in the semen dilution agent, as well as to emphasize the importance of microbiological monitoring of the boar mucous membranes and ambient surfaces before and during their exploitation. Such an examination could contribute to the interchangeable design of the dilution agent for the boar semen relative to the antibiotic content.Resistant strains of bacteria from prepuce swabs and swabs taken from the facility, as well as from native boar semen were isolated. The presence of these bacteria affected the quality of the semen. In conclusion, it should be pointed out that bacterial monitoring of the prepuce and surface of the facility can indicate possible problems related to the quality of semen, and that the design of the dilution agent for boar semen should be adjusted to the established resistance of isolated bacteria.

The most important stressors in our country are unfavourable climatic and nutritional conditions. Extreme deviations in climatic and nutritional conditions are immediate stressors for the body of sheep and goats. Appetite in sheep and goats decreases if they are exposed to extremely high ambient temperatures, while cold increases the body's energy needs and leads to the mobilization of fat from body fat and the consequent oxidation of fat and the formation of non-esterified fatty acids. Thyroid activity is reduced when these animals are exposed to high temperatures, and increased when they are exposed to cold. In an environment with high temperatures, blood glucose and cholesterol concentrations decrease due to unsuccessful maintenance of homeostasis. Sheep and goats are naturally kept in a group, which basically protects them from predators. They successfully register the action of new stimuli, especially noise and sudden movements of nearby predators. Early weaning breaks the bond between mother and offspring and adversely affects the development of normal behavioural relationships in lambs and kids, because artificial feeding systems do not fully meet the needs of oral activity, so sucking of the umbilical and scrotal region often occurs. Investigations of the influence of various technological procedures on the reactivity of the adrenal cortex indicate that the separation of the animal from the herd and immobilization are the most significant stimuli. Electrical stunning of sheep at the slaughterhouse causes significant stimulation of the sympathetic system with a sudden release of adrenaline and noradrenaline. In conditions of intensive production, the most significant stressors and physiological conditions that lead to stress are: parturition, birth, puerperal period, weaning, oestrus, high pregnancy, various surgical procedures, veterinary and zootechnical procedures, extreme variations of microand macroclimatic conditions, variations in quantity and food quality, etc.

The purpose of this study was to investigate oestrus synchronization efficiency and ram maturity effect on fertility of ewes of MIS sheep population during summer season. Research was performed on the experimental sheep farm of the Institute for Animal Husbandry in Belgrade, Serbia. The study included 70 crossbred ewes of MIS sheep population (Pirot Pramenka, Merinolandschaf and Ile de France breed) and 3 Ile de France rams (2 young, sexually unexperienced rams and 1 mature ram). Oestrus was synchronized in all 70 ewes using progestagen impregnated vaginal sponges (30 mg fluorogestone acetate) in combination with 500 IU PMSG. Ewes were mated with rams 48 h later. Obtained fertility and productivity results were as follows: lambing rate 57.14% (40/70), gestation length 147.11, litter size 1.82, stillborn rate 15.07%, birth weight of lambs 4.29 kg and body weight of lambs at 30 days of age 13.07 kg on average. Based on the results obtained in this study it was concluded that presented oestrus synchronization and mating protocol yielded lower than expected lambing rate. The effect of ram maturity on lambing rate was significant (P

Quantitative genetic analysis of variability and relationship of lambs body weight traits in indigenous pirot sheep population are done. The the examined lambs had high variability which very suitable for selection on a larger weight. There is a high and very significant correlation between the body weight of lambs with 30 and 60 days (.969 **) and the weight with 30 and 90 days ( .914 **). There is also a highly significant correlation between the weights of lambs with 60 and 90 days of age (.904 **). From our research, we can see that the first month of the lamb's life is very important for the further development of the body. There is different level of correlation between weight of lambs. This gives us an idea to say that many paragenetic factors are crucial for the growth of lambs from birth to weaning. The coefficient of multiple determination (R2) is 0.845 which means that 8.45% of the lamb's body weight variance at 90 days is determined by the variance of the set of predictor variables (PI-60, 30, 1). Each increase in lamb body weight during the observed periods of age is associated with an increase in the score of depending variable PI90. In particular, any increase in lamb body weight at birth by 1 kg is associated with an increase in lamb body weight from 90 days by 0.238 kg.

Records of female lambs and their parents of the Mis sheep breed have used. All animals are approximately have weaned at 90 days of age. Descriptive statistics, paired sample test, paired differences, measures of association, correlations and regression of body weights between female lambs and their parents have done. A complementary least body weights at 30 days and weaning between dams and lambs but utmost weight at 30 days, the lambs were higher while at weaning, the dams had higher weight. It can observe that the averages on body weights the rams were the highest, followed by lambs and the lowest the dams' body weights. The coefficient of determination of R2 varies from low to high, indicating that the lamb's body weight has more influenced by other factors that we have not considered.There were significant correlations between lamb body weight at birth and sire/dam body weight at birth. The results showed highly significant correlations of lamb's body weight at 30 days with dams but with sires, positive and very low. There had positive but no significant correlation between lamb body weight at weaning and sire body weight at weaning. Lamb body weight at weaning and dam body weight at weaning are highly correlated.

In addition to nutritional value, a very important criterion for the selection of meat, for the modern consumer is the health aspect, i.e. the content of fat and the profile of fatty acids in meat. The content of fat and fatty acids, among other things, is conditioned by the feeding system and the rearing method. Lambs fed on pasture have a lower share of fat in the carcass than animals fed with a concentrated mixture, in a closed system. The recommended value for the ratio of polyunsaturated to saturated fatty acids is up to 0.45, and below 4.0 for the n-6 and n-3 fatty acids ratio. Taking into account that the influence of lamb nutrition on these relationships is significant, modelling of fatty acid composition should be directed to the lamb nutrition system which leads to a decrease in the content of saturated and an increase in the concentration of polyunsaturated (PUFA) fatty acids in meat. A feeding strategy involving a grazing feeding system of lambs results in a higher content of n-3 PUFA, CLA and a more favourable n-6/n-3 ratio of fatty acids, while the lamb meat originating from animals fed concentrated diets has a higher proportion of n-6 PUFA and a higher n-6 ratio/n-3 fatty acids, which exceeds the recommended value of 4.0. Conjugated linoleic acid (CLA) is of great importance since it has an anticancer, antidiabetic effect as well as an effect on the immune system, suggesting a direction for future research on lamb meat.

In this review paper, contradictions in modern livestock production as dilemmas of farm animal welfare are considered. The main dilemma concerns the question of whether extensive production in small farms is generally better than intensive production in large farms. The next dilemma relates to an intensive selection of animals and its impact on the emergence of welfare problems. Another dilemma is related to the two main interconnected problems of pig welfare in individual farrowing pens: the piglet death by crushing and the sows' movement restriction. Similarly, welfare dilemma is the paradox of parent flocks of broiler line breeding that could not be solved until the pressure for genetic advancement in production is required due to the economic efficiency. The next example of the dilemma is the widespread practice of tail docking in piglets in order to reduce the risk of tail biting. Although the tail docking is painful and may cause death, anaesthesia is usually not applied on farms. A similar example of the dilemma is debeaking in the laying hens and the occurrence of feather pecking in free rearing systems. It is important to notice the difference between the described dilemmas, where one premise opposes the other, which is essentially a conflict between the animal welfare goals and other values, such as economic, ethical and moral issues. Finally, there are also some dilemmas about the consumers' willingness to pay a higher price of products that originate from welfare friendly rearing conditions.

The objective of this research paper was to estimate heritability coefficients (heritability) of growth traits in the lambs of indigenous Sjenicka Pramenka breed. The research was conducted on a sample which included 421 lambs the descendants of 15 sires and 187 sheep-dams, raised on 3 private farms in Kolubarski district, Serbia. The effect of fixed factors was studied while the values of heritability coefficients were estimated within the frame of SAS software package. A statistically highly significant (**=P

The main goal of this research was to examine, using modern methods, the variability of phenotypic correlations of production performances and reproductive properties of Simmental cows reared on the farms of individual agricultural producers, in different breeding areas of the Republic of Serbia. The study of phenotypic correlations of milk performance and fertility properties in different regions of Serbia was carried out on a total of 3.056 primi parous Simmental heifers under control, with lactations completed within one year. The examined animals were reared on different individual farms, and mainly in very different conditions of housing and nutrition, depending on the breeding area. The study of phenotypic correlations included the following milk performance traits: milk yield, milk fat content, milk fat yield, yield of 4% corrected milk; and fertility properties: age at first calving and service period. The results of the study among other things indicate that although the phenotypic correlations between the fertility and milk performance properties show different degrees of variation, they should be taken into account in the final assessment of the breeding value of the animal, so that the breeding selection programs are more comprehensively designes.

The purpose of this study was to determine status, number and present level of productivity of autochthonous goats raised in Central Serbia on smallholder farms. Study included quality breeding animals of Balkan and Serbian white goat breed registered in Central herd book. Productivity data were collected from regular annual performance recordings at 11 smallholder farms for 145 Balkan does (2-9 years of age) and 203 kids and 83 Serbian white does (2-10 years of age) and 109 kids. Traits recorded were as follows: body weight of does, body weight of kids at birth, at the age of 30 days and at weaning, prolificacy of does and milk production. The analysis showed the average body weight of does to be 43.07 kg for Balkan does and 47.42 kg for Serbian white does. Average body weight of kids at birth, 30 days of age and weaning was 2.22 kg, 6.87 kg and 15.71 kg, respectively for Balkan breed and 3.66 kg, 7.24 kg and 14.23 kg for Serbian white breed. Prolificacy was 140% in Balkan and 131% in Serbian white does. Among dairy production traits, following results were obtained for Balkan and Serbian white goat respectively: lactation length 199 and 229 days, total milk yield 257.89 kg and 459.49 kg, milk fat content 4.03% and 3.79%, milk protein content 3.06% and 3.35%. Number of quality breeding animals registered at Central herd book in 2018, as presented in Institute for Animal Husbandry's annual report for goats for Central Serbia in 2018, was 159 for Balkan and 138 for Serbian white goat. As these breeds represent a valuable and irreplaceable source of genetic variability, as well as very important cultural and traditional heritage and further emphasis should be on preserving and increasing their number.

From locally adapted sheep and goat breeds in Central Serbia pramenka (with its ecotypes), and Balkan and Serbian white goat are present. These breeds differ by morphological, reproductive and productive traits and their differentiation was affected by specific climatic, hydrological and nutritional conditions. Thanks to that, these breeds are characterized by the wide adaptability, disease resistance, expressed maternal instinct, relatively high fertility and a long productive life-time. The productivity of these genotypes is relatively low, which led to a drastic reduction in the number of head of locally adapted breeds, simultaneously emphasizing the more productive genotypes. These trends led to loss of genetic diversity. The consequence of these practices in sheep and goat farming is that most of the locally adapted races are endangered in different degrees (from high to critically endangered), according to the criteria of the valid Rulebook. Genotypes of sheep and goat observed in this study belong to a group of genetic resources. According to the Institute for animal husbandry's annual report for Central Serbia in 2017, number of heads for most of locally adapted breeds is in slight increase, but still is not satisfactory. Thus, the number of active animals registered in flockbook for sheep and goats by races are 10386 for Svrljig pramenka, 686 Lipa pramenka, Krivovir pramenka 616, Karakachan pramenka 139, Pirot pramenka 124, Bardoka 94 animals, Balkan goat 121 and Serbian white goat 145 animals. The highest values of live body weight (BW) for the lamb were found in the Lipa lambs (BW at birth 3,44 kg, BW after 30 days 11,79 kg and BW at weaning 27,92 kg), and the Serbian white goat's kids (BW at birth 2,56 kg, BW after 30 days 7.68 kg and BW at weaning 16,04 kg). The highest fertility indexes were observed in Svrljig strain (1,28) and the Balkan goats (1,51). The protection and conservation of sheep and goat genetic resources in the Republic of Serbia is still insufficient, although there is a shift in their conservation. However, urgent protection measures must be taken in the form of in situ and ex situ conservation to prevent the loss of genetic resources forever.

Selenium is a trace element, which stimulates antioxidant defenses and improves reproductive functions in human and animals, under the form of selenoproteins. The objective of the study was to evaluate the effect of selenium, supplemented as inorganic or organic form in the diet of stud rams, on some of their semen parameters. The experiment was performed with 15 clinically healthy rams from North East Bulgarian merino breed. The animals were divided in three groups (5 per group). The rams from first experimental group (G1) received a diet with supplementation of 4,0mg sodium selenite (Na2SeO3) per animal per day, while the animals of the second experimental group (G2) obtained diet with 1.83g L-selenomethionine (Sel-Plex, Alltech, USA) per animal per day. Eventually, each animal from the G1 and G2 received 1.83g selenium per day. The control group (GC) received a diet without supplementation of selenium. The principal composition of the diet in each group was the same. The ejaculates were obtained via artificial vagina. The evaluated parameters were volume and pH of the ejaculates and motility, concentration and in vitro survivability of the spermatozoa at 39˚S for 360 min. It was found that the supplementation of ram studs diet either with inorganic and organic selenium led to increase in the volume of the ejaculates, motility and survivability of the spermatozoa. The pH of the freshly obtained semen was not affected by selenium treatment.

The effect of Eco-fish meal, as an alternative to fish meal, on the production performance of the lambs of the Mis population in the intensive fattening, was investigated. The experiment was carried out on 40 lambs, the average age of 30 days, divided in 2 groups. In addition to mother's milk, the lambs were given a concentrated mixture and a lucerne hay, at will. Isoprotein forage mixtures (16% of total proteins) differed in terms of the protein component. The protein source for treatment I had fish meal, while the animals on treatment II consumed EcoFish, a herbal substitute for fish meal, which consisted of domestic foods of known origin such as genetically unmodified and thermally treated meal of decorticated soybean grains, soybean protein isolates, gluten, livestock yeast with the addition of minerals, amino acids, vitamins, enzymes and other additives. Statistical processing of the obtained data was done using the SPSS STATISTICA, Version 20. On treatments I and II, the average daily lamb gain was 320 and 283 g, respectively, without statistical significance. The consumption of dry matter and proteins in analogue treatments was 0.819 and 0.823 kg, and 152.62 and 157.04 g, respectively. The dry matter consumption per kilogram of gain (kg/kg of gain) was 2.56 and 2.91; of energy (MJ NEM/kg): 17.65 and 20.25; of total proteins: 476.9 and 554.9 g, respectively. The protein efficiency ratio - PER (g of gain/g of consumed protein) in analogue treatments was: 2.09 and 1.80. There were no statistically significant differences between examined treatments (P> 0.05). Considering that the source of protein did not significantly affect the intensity of growth and the use of food by lambs of Mis population in intensive fattening (P>0.05), fish meal can be replaced by Eco-fish meal - plant protein, since according to Commission Decision 9/2001 on BCE protection (OJEC, 2001), there is a distance to the use of fish meal, as a source of protein.

Determining the degree of correlation between two or more traits depends to a large extent on their manifestation. The knowledge of genetic and phenotypic correlations between body characteristics of the animal and product characteristics can help define the breeding goal, but also to define and harmonize the assessment criteria. Although the phenotypic and genetic correlations between the traits of body development and type and the milk yield show different degrees of variation, they should be taken into account in the final assessment of the breeding value of the animal so that the selection programs are more comprehesively defined. The examination of phenotypic correlations of linear assessment scores of the type, milk and fertility traits was performed on a total of 303 cows of the Simental breed in the first three lactations. The examination of phenotypic correlations included the following milk performance properties in the first three standard lactations: milk yield, milk fat content, milk fat yield, yield of 4% corrected milk; also fertility traits: age at current calving and service period in each lactation; while the linear type scoring included a group of traits: type or frame, muscularity, fundament, udder.

The investigation was conducted in population of Mis breed of sheep, divided into three groups. For reproduction had use rams of Ile de France breed. Induction and synchronization of oestrus was done off-season in October. The percentage of lambing sheep, sheep fertility, and number of lambs acquired per father, sex and birth type of lambs were observed. Ram 1 had a highest number of ewes lambed with an excellent percentage of mating success and highest fertility rate of ewes with differences on fertility rate of 17% (between group of ewes in ram 1 and ram 2), 36% (group of ewes in ram 1 and ram 3) and 19% (group of ewes in ram 2 and ram 3).The highest birth weight were on lambs born single from ram 3, born twins from ram1, triplets of ram 3. For the lambs born quadruplets (unfortunately only in rams 1 and 2 with one lamb of each was alive) the lamb of ram 2 was higher in birth weight. The male and female lambs of ram 3 got the highest birth weight while the female lambs of ram 1 acquired the lowest birth weight. The highest average birth weight of lambs was born single, male; born triplets' male from lambs of ram 3 having an average birth weight of 6.36kg and 4.0 kg but got the lowest for lambs born twins on female lambs 3.66 kg. The male lambs of ram 1 got the highest average birth weight on lambs born twins with an average birth weight of 4.38 kg but the lowest on triplets born 3.3kg. Unfortunately only one each of the two ram with lambs born quadruplets alive both male and the higher was that lamb of ram 2 with a birth weight of 3.3 kg. Result showed the influence of ram on number of lambs born and lambs' birth weight. Between subject effects Father* birth type showed a significant effect on birth weight of lambs.

Some problems of modern analysis of the genome of domestic animals and the possibility of applying the results of the research in the selection have considered. Molecular genome analysis has progressed rapidly. Today, using modern DNA analysis, the domestic animals breeding value can be safely foreseen. Based on the scientist's intuition of early-20th century, after half a century, genetic markers had discovered. Thus, the traditional selection method has integrated with molecular techniques of selection by applying marker-assisted selection (MAS). Microsatellites have attracted great attention from scientists because they are widespread in the genome and have a high level of polymorphism. Thousands of SNPs have discovered with their exact position in the genome. This very reliable method occurred for analyzing the genome which shows the change of only one nucleotide base into the DNA molecule. All modern achievements of molecular genetics have opened the way for practical application in the selection of all kinds of domestic animals. Today, a combination of molecular or genomic selection combined with a traditional is very reliable method for a faster, more accurate assessment of the breeding value of animals.

It is proposed to grow rabbits in the modern production technology with the use of the developed technology of using recycled materials in the construction of cages for keeping rabbits. It is also proposed to use interbreed crossing of New Zealand White breed and Flanders, and also breeds Californian and Flanders breed.

The aim of the present study was to obtain relevant results related to the basic indicators of fertility and milk yield of Simmental cows, in production conditions on farms of agricultural producers, using appropriate mathematical and statistical procedures, i.e. to determine the influence of bull sires originating from Serbia, Austria and Germany on the implementation of the main breeding program and improvement of production traits of Simmental cows on the territory of Šumadija district. The study of the effect of bull sires who are originally from Serbia, Austria and Germany on performance traits of Simmental cows included a total of 303 cows in first three lactations. Milk production of cows descendents of bulls from the German population was higher compared with the production of cows originating from Austria in the first lactation by 58.29 kg and in the third by 67.72 kg, but in the second it was lower by 12.31 kg. The variability of age at first calving ranged from 766.93 (cows progeny of domestic bulls) to 813.06 days (cows progeny Austrian bulls). Average duration of service period had the interval of variation of 86.80 in cows from domestic bulls in the third lactation to 109.88 days in cows originating from Austrian bulls in the first lactation.

The experiment included 30 lambs-crosses F1 generation: Pirot Pramenka (50%) x Württemberg (50%) and 30 crossbred F1 generations: Pirot Pramenka (12.5%) x Württemberg(37.5) x Ille de France (50%), weaned at 60 days of age, the average body weight of 18.0 kg. The mixtures varied in protein source: I - sunflower meal, II - soybean meal and III - fish meal. The share of undegradable protein was 43 : 51 : 58 %. The average diameter of the fibres in lambs on treatments I:II:III was 26.14 : 24.96 : 25.20 μm, and of two-breed (PxW) and three-breed (PxWxIDF) crosses: 25.38 and 25.49 μm. The average height of the wool fibre in lambs on treatments I:II:III was: 2.97 : 3.06 : 3.17 cm, and in two-breed (PxW) and three-breed (PxWxIDF) crosses 2.98 : 3.15 cm. The average length of the fibre in lambs on protein sources I:II:III was 4.62 : 5.08 : 5.11 cm and in two-breed (PXW) and three-breed (PxWxIDF) crosses 4.77 : 5.11 cm. Protein source in feed mixtures, and genotype of lambs significantly influenced the quality of wool expressed through diameter, height and length of the fibres.

Basic principles of biosecurity plans creation and inplementation were given in this review paper. This include goals wanted to be acheived related to specificities of dairy farm technology, sellection of measures that have to be included, order and manner of measures description, inplementation, as well as failures in plan execution. Efficiacy and further sustainibility of biosecurity plans inplementation could be measured through differences between biosecurity level before and after plans application established by questionnaire about biosecurity indicators, such as: 1. isolation of the farm and its organization, 2. quarantine and newly purchased cows policy, 3. visitors policy, 4. attitude towards equipment use, 5. pest control, 6. sanitation efficasy and 7. farm impact on environment. The stakeholders have to define and develop plan to keep potential pathogens for dairy herd health and production in cooperation with the veterinarian and the other professionals advising on organisation and production technology. At least once a year, it is necessary to reconsider the plan and supplemented by new practical experience and scientific knowledge.