Abstract
This paper describes the results from a one-year field survey at a dairy farm. The aim of the study has been to explore the relationship between thermal and aerial environment (i. e. weather conditions, thermal environment and air quality in barn) and animal behaviour in an open-type cattle house.
The examined cattle house was located near Chitose-City, Hokkaido, Japan, where the weather is relatively snowy and windy. The temperatures can be below -10°C in winter. A few days in summer, hot weather with temperatures above 30°C can be expected.
The field survey consisted of so-called 24-hour observations and morning observations carried out subsequent to the morning feedings. The 24-hour observations were carried out once in winter and once in summer. Four winter morning observations and four summer morning observations were made in the periods from December 1997 to February 1998 and from May to July 1998, respectively. On the basis of the results from the survey the following conclusions may be drawn:
1. The cows' preferences for feed, the stalls and the paddock were influenced by the seasons. In winter, some of cows preferred to lie in the stall at the time of feeding. The winter morning observations showed that the paddock and the stalls were almost used equally, while in the summer, the cows preferred to lie in the stall after eating.
2. Multiple regression analyses of the morning observation data showed that the predictor variables “time from feeding”, “indoor temperature”, “solar intensity” and “wind velocity components” could explain 60-70% of the variances in the cows' preferences for different places, i. e. eating area, stalls and paddock, in winter. While in summer, the predictor variables “time from feeding” and “solar intensity” could alone explain more than 90% of the variances of cows' preferences for eating area and stalls.
3. In order to obtain a better understanding about the air quality in open type animal buildings, further studies on variations in bacteria concentrations in a building under different ventilation conditions are desired.
