Effect of barn ventilation on blood gas status and some physiological traits of dairy cows.

Twenty Holstein friesian and Brown swiss cows were used to investigate the effect of insufficient in barn ventilation on blood gas status and some physiological traits of the cows. Animals were kept in mechanically ventilated barn in stall barn (I); and the ventilation funnels of the barn were closed to simulate traditional habits of the region's breeders (II); then cows were transfered open-shed barn (III). For each experimental of 10 days period, respiration and pulse rates and blood gas of animals were measured. Temperature, relative humidity, CO2 and NH3 concentrations were recorded in each barns. In mechanically ventilated barn, climatic and atmospheric gas was in normal ranges for the cows but in unventilated barn they were at the upper levels. In experiment II, blood pH was decreased without pCO2 change. The highest blood pO2 and HCO3(-) levels were found when the animals were kept in open-shed barn (III). Measured parameters were not influenced by breed of the cows. Blood pH, pO2 HCO3(-), respiration and pulse rates of the cows were significantly affected by barn types (p < 0.05 and p < 0.01). Respiration and pulse rates were higher in inadequate (II) barn conditions than those of open-shed. Higher levels of gases, especially carbon dioxide, in the unventilated barn significantly influenced biological parameters of cows. It is concluded that poor ventilation caused considerable changes in physiologic parameters of the cows and can potentially affect animal health and production.