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 trial was designed in order to examine the impact of flax seed in the nutrition of young cattle/bulls, in the final stage of the fattening. In the trial, 30 bulls of Simmental breed of uniform initial weight were selected, divided into 2 groups (control and experimental). The control animal group did not consume flax seed as a food supplement. Cattle of the experimental group consumed flax seed in an amount of 3.75% (300 g per day) of concentrated meal in the last 90 days of fattening, i.e. 300 g per day. The study included the examination of the fattening performance, slaughter traits and the composition of the bovine carcass. After slaughtering, warm carcass sides, with and without kidneys, were measured individually. Subsequent to period of cooling, the left carcass side it was cut into the main carcass parts according to the Rulebook. The results of the study showed that the addition of flax seed in the diet did not have a statistically significant effect on the body weight of bulls at the end of the trial. It was found that the addition of flax seed in the feed during the final stage of fattening did not have an impact on the differences in the average overall gain of bulls and the feed conversion ratio. Based on the data obtained by cutting of carcass sides to main parts, it was established that feeding with flax seeds had no significant effect on the share of carcass parts.

The farm animal welfare science has undergone a thorny path of development, often disputed because of its lack of measurability and the purpose of existence. At the very beginning, primarily based on moral and ethical attitudes, over time it pointed to the importance of meeting the needs of animals and the consequences of their neglect and exhaustion in the conditions of intensive livestock production. An important segment of its development was the definition and development of methodologies for the assessment of welfare indicators, which made it measurable and accepted as a scientific discipline with the knowledge applicable and useful in modern production systems. This paper is a concise review of the evolution of the animal welfare science, but also an indication of its future in the context of the development of "symbiotic" connections with the concepts of sustainable agriculture and food safety as integral parts of the modern ecological movement arose from a unified concern for the welfare of people and animals, a care for planetary welfare in general.

In the last decades, there has been a trend present in the world to increase the size of dairy herds while increasing the yield of milk per head. In addition to environmental and economic benefits, this trend carries certain risks for the welfare of cows because in conditions of increased agglomeration of cattle the possibility of spreading of pathogens is also increased, there are less opportunities for adequate control and cows are exposed to greater selection and production stress. Research of the relationship between herd size and welfare quality parameters is still not sufficient to make relevant conclusions. Starting from that, the aim of this study, conducted in Serbia, is to examine the influence of herd size on parameters related to providing good feeding and housing conditions as important segments of the overall welfare of dairy cows. The assessment of given welfare parameters was done by Welfare Quality? Assessment Protocol for Cattle (2009) on 16 dairy farms of different herd sizes (large, medium and small) and housing management. The results indicate that there are significant variations in welfare indicators in each of the observed groups, which is why the size of the herd cannot be taken as a parameter that explicitly determines the quality of welfare. However, individual observation and comparison of welfare parameters between groups indicate that small herds in our production conditions could be identified as the greatest risks to the welfare of cows. In small herds, the highest share of cows of poor (4.62%) and fattened condition (8.76%) was found, as well as the lowest freedom of movement because cows on small farms are mostly reared in a tied system. Average values of indicators: lying down time (6.24s), frequency of collisions with equipment (13.25%) and high dirt contamination of cows (65.6-89.8%) further emphasize the issue of providing comfort in small herds.

Microclimatic conditions in facilities for housing and rearing young category of breeding dairy cattle at the first 30 days after birth, have a significant impact on the quality of welfare, especially in intensive production. The parameters most often taken into account when evaluating microclimate conditions are: temperature and air humidity, the mutual relationship of which represents the THI (temperature-humid index) index; speed of air flow; air quality (presence of dust and ammonia) and level of light in the facility. The quality of the microclimate in the facilities is directly influenced by the climatic conditions in the external environment, therefore study period on 2 farms (A and B) with an intensive production system was divided into 4 seasons (autumn, winter, spring and summer). Holstein Friesian calves were observed in the period from birth to 30 days of age. The worst microclimatic conditions were recorded during the summer season on both farms (1129 on farm A and 1114 calves on farm B suffered), while the situation was more favorable during the colder period. Also, the best conditions, on both farms, were provided for calves in the first 7 days of life. The most unfavorable impact was the high air temperature, while the air flow, paradoxically, improved the air quality, especially during that period. The overall welfare quality score was similar on the observed farms, 2.25 on farm A and 2.12 on farm B, which can be considered acceptable. At the same time, it indicates the presence of serious problems, the solution of which must be approached most seriously.

The aim of this study was to analyze the overall welfare state on Serbian dairy farms, as well to suggest measures for its improvement. The assessment was done according to Welfare Quality? Assessment Protocol for Dairy Cows on 16 selected commercial farms in which the cows of Simmental and Holstein-Friesian breeds were reared (N=4833). Welfare state on each farm was evaluated by relevant measures that indicated insurance of appropriate feeding, housing, health and behavior as basic principles of welfare. Overall score (0-100 points) enabled finally categorization of farms into one of four welfare category (not classified, acceptable, enhanced and excellent).Based on results, half of the farms were assigned to acceptable, and other half to enhanced welfare category. Housing conditions on the majority of farms (63%) were assessed as unacceptable (?20 points) due to poor hygiene and discomfort. Cows were kept tied continuously on more than one third of farms which together with lack of pasture (17 days/year on average) restricting their comfort and freedom of movement. This may be also linked to low scored behavioral insurance (32points), especially inability to express its natural forms (6.7 points).Health condition was estimated as acceptable, but endangered welfare by high incidence of laminitis (38%), distocya (4.2%) and mortality (6.7%). Commonly performed dehorning procedure (79%) without anesthetic/analgesic application caused pain and stress in affected animals. Overall assessment score (2.5/5) showed the need for improvement in all areas of dairy cows' welfare, especially in terms of their housing and management.