Development of Methodology to Decrease the Air Pollution (ammonia Emission) from Dairy Simmental Farms

This research aimed to define the variations in nitrogen associated compounds (daily urea content in milk, milk urea nitrogen, and ammonia emission) in milk samples of Simmental first parity cows bred in Eastern Croatia based on the season of milk recording. For statistical analysis, test-day records of first parity Simmentals bred in Eastern Croatia were used. Table 3 shows the results of the analysis of variance of daily urea content in milk, milk urea nitrogen, and ammonia emission of Simmental first parity cows concerning the season (spring, summer, autumn, and winter). According to the seasons, all analysed traits differ statistically highly significant (p < 0.001). The highest content of daily milk urea was recorded in summer (26.926 mg/dl), also, milk produced in summer had the highest MUN (12.386 mg/dl) as well as the highest ammonia emission (87.302 g/cow daily). The lowest content of daily milk urea (18.828 mg/dl) was determined in winter, along with the lowest milk urea nitrogen (8.661 mg/dl) and ammonia emission (68.565 g/cow daily). The results of the research show that the variability of daily milk urea content, milk urea nitrogen and ammonia emission in Simmental first parity cows depends on stage of lactation, daily milk production, age at first calving, and season of milk recording. Consequently, for the evaluation of ammonia emission from dairy cattle farms based on milk recording data, these outcomes should be taken into consideration in the statistical model. Finally, since it is not yet applied, the application of this evaluation methodology should decrease the environmental impact (especially air pollution) of dairy farms and increase the quality of life in the region of Southeast Europe.