The main goal of this paper was to investigate the influence of some additives included into high yielding dairy cows rations to overcome the problems in early lactation. These substances directly affect the productive performances of dairy cows as well as udder health. The commercial name of investigated preparation is 'YEASTURE' and it is composed of live yeast cultures selected from three strains Saccharomyces cerevisisiae in combination with probiotic bacteria and enzymes (Lactobacillus casei, Streptococcus faecium, Aspergillus oryzae, Lactobacillus acidophilus, 1,3-b and 1,6 D-Glucan, hemicellulase, Protease, Cellulase, Alpha amylase) which have the ability to modify the fermentation in rumen stimulating the development of ruminal bacteria and increasing the fibre digestion. Effects of this preparation have been investigated on 60 Holstein-Friesian cows divided into two groups. The diets were identical, and trial group received also 10 g of preparation Yeasture daily. Application of Yeasture started 15 days prior to calving and lasted until 60th day of lactation As a research result improved in vitro disappearance of diet dry matter from roughage (alfalfa hay, maize silage and ensiled sugar beet pulp) was established. Preparation Yeasture influenced quantity and composition of the milk. The difference between trial and control group was 2.57 kg 4%FCM or 8.70% (P<0.01) and 7.16% milk fat (P<0.05).Trial group supplemented with Yeasture showed lower somatic cells count by 7.3 percent points what indicated better health of cow's udder. Based on the presented results it can be concluded that inclusion of preparation Yeasture into diets for dairy cows in transition period can be recommended.

Consumers are becoming more aware of the relationships between diet and health and this has increased consumer interest in the nutritional value of foods. This is impacting on the demand for foods which contain functional components that play important roles in health maintenance and disease prevention. Vitamin E, organically bound selenium and betacarotene are important antioxidant components of animal and human diets, and also unsaturated fatty acids and yeast and their roles in animal and human health and immune function are indispensable. The present review paper will discuss these nutrients in relation to antioxidant and health considerations and draw conclusions as to vitamin and mineral supplementation needs.

The aim of the study was to determine effect of environmental and paragenetic factors on body mass of lambs at birth. Investigation was realised on experimental sheep farm of Institute for Animal Husbandry, Belgrade-Zemun. Animal included in this research were representatives of Mis sheep population. The results of the research confirm that values of the birth mass range from 4.43 kg to 4,58 kg observed by years and 4.48 kg to 4.55 kg depending on the lambing season. Statistical analysis showed that the existing differences still significant on the level (P <0.05). Variations of body mass in lambs depending on the mother's age range in the interval from 4.29 kg to 4.52 kg kg and statistically very significant(P<0.01). Type of birth has also expressed a significant effect on the body mass of lambs at birth and variations range from 4.31 kg (twins) to 4.59 kg (single). Existing differences was statistically very significant (P<0.01). Average body mass in lambs depending on sex of lamb were almost the same, 4.54 kg male and 4.52 kg female, and the difference is not statistically significant (P> 0.05).

The aim of this study was to determine the influence of environmental factors affecting body weight variability of lambs in two crossbreed groups: Pirot x Württemberg and Sjenica x Württemberg. Both populations were managed under the same farm conditions. The data were analyzed to determine the effect of age of the dam, weight of dam, birth type, sex, year and season, on the birth weight and weaning weight of crossbreed lambs. Statistical analysis was performed by GLM procedure using the SPSS statistical package program. The average birth weight of Pirot x Württemberg lambs was 3.56 kg while Sjenica x Württemberg lambs was slightly higher at 3.69 kg. The difference on birth weight between the two crosses was not statistically significant (P>0.05). The average weaning weight of Pirot x Württemberg lambs was 23.54 kg while Sjenica x Württemberg lambs had higher weight at 24.37 kg. The difference of 0.83 kg on weaning weight was statistically significant (P <0.05). Body weight, depending on the environmental factors, ranged from 3.17 to 3.96 kg at birth and from 22.12 to 24.18 kg at weaning in Pirot x Württemberg lambs. Body weight of Sjenica x Württemberg lambs ranged from 3.39 to 3.99 kg at birth and from 22.69 to 25.44 kg at weaning. Statistical analysis showed that the differences were statistically significant (P<0.05) and highly significant (P<0.01).

With recent developments in DNA technologies, a large number of genetic polymorphisms at DNA sequence level has been introduced over the last decades as named DNA-based markers. The discovery of new class of DNA profiling markers has facilitated the development of marker-based gene tags, mapbased cloning of livestock important genes, variability studies, phylogenetic analysis, synteny mapping, marker-assisted selection of favourable genotypes, etc. The most commonly used DNA-based markers have advantages over the traditional phenotypic and biochemical markers since they provide data that can be analyzed objectively. In this article the main applications of molecular markers in present-day breeding strategies for livestock improvement - parentage determination, genetic distance estimation, genetic diversity, gene mapping and marker-assisted selection have been reviewed.

Research was conducted on animals of Balkan goat breed. The impact of environmental factors on the weight of kids was analyzed, and also the value of genetic parameters of growth traits of kids to weaning had been examined. The body weight of kids varied depending on the year from 2.27±0.09 kg to 2.43±0.08 kg at birth and 10.81±0.58 kg to 11.13±0.51 kg at weaning. Variations depending on the season, ranged from 2.24±0.09 kg to 2.51±0.05 kg. Sex also had an impact because the male kids had higher weight of 0.12 kg at birth and 0.20 kg at weaning. All differences caused by environmental factors were statistically significant (P<0.01). Single born kids in comparison with twin born kids had higher birth weight by 0.22 kg at birth and 0.37 kg in weaning. The differences were statistically significant (P<0.01). It is a known fact that the increase in litter size influences decrease in body weight of kids. We also found that the weight at birth is associated with body weight at weaning. Heritability for growth traits observed moving in the range of low values from 0.102 ± 0.039 to 0.153 ± 0.041. Repeatability of the observed traits varied from low to medium values in the interval from 0.118 ± 0.030 to 0.528 ± 0025.

The objective of the present study was to investigate nutritional and metabolic status in Simmental cows during early and mid-lactation. Fifteen early lactating cows and 15 mid lactating cows were chosen for the investigation. Blood samples were collected to measure beta-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), triglycerides (TG), glucose and the activity of aspartate transaminase (AST). Early lactation as compared to mid lactating cows were found to have significantly higher (P<0.05) blood serum concentrations of NEFA, BHB and AST and lower blood serum concentrations of glucose (P<0.05) and TG (P>0.05). Significantly negative correlations were observed between BHB and glucose (P<0.01), BHB and TG (P<0.05), NEFA and glucose (P<0.05). Significantly positive correlations were observed between NEFA and BHB (P<0.05), NEFA and AST (P<0.05), glucose and TG (P<0.01). The results suggest that these parameters can serve as useful indicators of the nutritional and metabolic status of dairy cows during lactation. [Projekat Ministarstva nauke Republike Srbije, br. TR 31001]

This paper analyzes the present state of sheep farming in Serbia and provide guidance for sustainable development in the future. It also discusses the challenges of the modern age that may affect the viability of sheep production. Today in Serbia grows less than 1.5 million sheep. In terms of breed structures, most of the population makes indigenous Pramenka sheep (80%), while the remaining 20% are: Tsigai, Merinolandschaf, Ile de France, Pirot improved, Mis sheep, and other less important population, as well as the crossbreed with foreign and local domestic sheep. However, due to the intense process of industrialization, from the second half of the twentieth century until today there is a trend of depopulation, demographic discharge of the village, which has resulted in reducing the farms so that the number of sheep in the past two decades fell by about 30%. The greatest reduction in the number of sheep registered in the nineties. After stabilization, a large decrease in the number of sheep was followed by the 2010th year and by 6% compared to 2008 year. Genetical improvement is significantly increased level of production of all species of domestic animals. However, animals selected for high and efficient production are exposed to greater risk. This primarily refers to the physiological and immunological problems, but would generally be said that all this leads to distortion of harmony between the organism and the environment and the repercussions on the molecular level. Sustainable development of sheep breeding in Serbia must be kept in mind this reality. New challenges facing the sheep breeding of Serbia, stems from a political orientation toward membership in the European Union. Sheep Serbia must find its place in this new challenge.