Five years study of seasonal variations of milk composition

Abstract

Serbia has the largest dairy sector in the Balkan region, producing about 1.55 million tons of milk per year. However, farms are still very small and fragmented, with 600,000 cows on 220,000 farms, giving an average herd size of 2.7 animals. The composition of cows' milk is of the greatest importance for the dairy industry. Compositional parameters were of interest from a nutritive and a technological point of view. In this study, 5945 milk samples were collected in Srem district in Vojvodina and analysed during 5 years (2010-2014) for milk fat, protein and non fat dry matter contents. Statistical analysis and estimates of the significance of the variation due to month and season was performed with the Kruscal-Wallis test. The mean milk fat content was 3.85%, the protein content 3.23% and non fat dry matter 8.46%. All investigated parameters showed significant seasonal variation (p<0.01). As expected, all three parameters were the lowest during summer months while the highest values were found during winter. Factors influencing the composition of milk are numerous including cows breed, feeding systems, milking frequency and milking systems. Compared with a previous investigation (1976) of milk composition in same part of country, milk fat and non fat dry matter contents increased, while protein content stayed constant. Data from developed countries indicated a higher fat and protein contents meaning that there is space for improvement of milk quality in our country.