This paper presents influence of direction and energy of wind on forming of ventilation air velocity in chosen area of the free stall barn during summer. Based on analysis of obtained measurement results characteristics of the wind speed in summer was made. Variability of the ventilation air velocity with take into account of perpendicular and parallel wind direction was determined. Noticed differentiation of air velocity depending on measurement place - central barn area was less ventilated than area close to wall. Proposals setting out the reasons for the abnormal air flow were formulated. In order to increased ventilation air velocity in central part of the barn recommended use to air mixers. Attention was drawn to need of continue studies of different barn types relative to building construction solution and its localization.
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The aim of this study was to analyze the existing barns in terms of cow maintenance systems, structure and technological solutions of buildings at large dairy farms in northern Poland. The studies were conducted in northern Poland in West Pomeranian, Pomeranian, Kuyavian-Pomeranian, Warmian-Masurian and Podlaskie voivodships. The study included field inventory and questionnaire studies at some chosen farms of these voivodships.The farm size criterion was set at the herd size of 150 or more head of cattle. Based on the obtained study results and their analysis, it was established that in northern Poland the highest number of large dairy farms (41%) was located in the Kuyavian-Pomeranian voivodship and the majority of dairy farms comprised 1-3 barns built of reinforced concrete and equipped with a gravity ventilation system. In all regions prevailed farms keeping 150 - 200 head of cattle and the largest average herd size of 460 head of cattle was in the West Pomeranian voivodship. The most often barns were equipped with herringbone milking parlours (45%) for 21-25 cows milked at once and the indoor feeding table (63%). ...
