Being a herbivore the ruminant deer (Capreolus capreolus L.) eats a large variety of feeds, the choice of which depends on the characteristics of the hunting grounds and the season of the year (Holisova

Analysis of the rumen content was carried out on a total of 43 samples taken from deer (Capreolus capreolus L.) shot on the hunting grounds of "Barajevska Reka" (Serbia). All animals were males and were hunted in the early morning. The experiment was set as a randomized trial with four treatments (spring, summer, autumn and winter) and an uneven distribution of animals per treatment. Organoleptic examination of the stomach content revealed that cereals were the most abundant feed ingested (present in 25% of summer samples and 62.5% autumn samples). Results of chemical analysis confirmed a significant seasonal influence on total nitrogen and protein content, fats, cellulose, ash, phosphorus, pH and ammonia nitrogen within the content of the rumen. Contrary to this, calcium within the dry matter and total mineral content varied regardless of the season. A significantly high protein (360.84 g/kg DM) and low cellulose content (170.30 g/kg) was present during the spring season. A high negative correlation (r=-0.7398) between protein and cellulose content was present throughout the year. The quantity of extracted non nitrogenous supstances was lowest during the winter period (152.10 g/kg). The highest pH value (6.33) was recorded during the winter season and in during the rest of the year it showed limited oscillations (5.52 – 5.62). The quantity of ammonia nitrogen was 1% of total nitrogen throughout the year. Considering the results of this study, and compared to the published literature data, it can be concluded that the high feeding selectivity of deer and the good quality of offered feedstuffs on the hunting grounds in Serbia are responsible for the high protein content in the rumen throughout all seasons.