HYGIENE EVALUATION OF THE VENTILATION AND HEAT-TECHNICAL QUALITIES OF BUILDINGS USED FOR FREE-BRED DAIRY COWS

Hristev Hristo, Ivanova Rumyana, Tasheva Smilyana

Abstract
   A hygienic evaluation of the ventilation and heat-technical qualities was made for three types of buildings used for free-bred dairy cows.
   Farmhouse 1 (FH 1) and Farmhouse 3 (FH 3) are semi-open, while Farmhouse 2 (FH 2) is closed. The provided living area for an animal in FH 1 is 8.06 m², in FH 2 - 11.5 m² and in FH 3 - 9.4 m².
   It was found that the actual air exchange in FH 1 and FH 3 is insufficient in both - winter and summer. In FH 2, actual air exchange in winter is about 2 times higher than required, while in summer it is also insufficient.
   The heat balance in winter for all three buildings is negative. The main reason for negative heath balance in FH 2 is low density of the population. The negative heat balance in FH 1, in both seasons, is a result of the high humidity of the use deep litter.
   It was also found that the zero balance (temperature difference) for FH 1 is 0.7°C, for FH 2 - 7.5°С and for FH 3 - 1.6°С.

Key words: hygienic evaluation, ventilation, heat balance, buildings for free-bred dairy cows