Effect Effect of Different Environmental Housing Conditions on Physiological Reactions of Growing Friesian Calves.

Abstract

Twenty two healthy growing Friesian calves were used to study their diurnal and seasonal physiological reactions as affected by two different housing types; semi open barn with concrete roof and semi closed barn with asbestos roof. The study included two seasons, winter (January to February) and summer (July and August), the measurements were taken at 08.00 hrs. and 14.00 hrs. The studied parameters were climatic conditions indoors and outdoors, thermal properties of building components (roof, walls and floors, thermal responses of animals, respiratory responses, hematological responses, leukocyte differential count and thyroid activity. The physical thermal properties of building components were tested at four times (06.00, 12.00, 15.00 and 20.00 hrs.) throughout the day. The housing components of the two barns showed significantly (P<0.01) seasonal and diurnal effects on all the physiological parameters of the calves. There were highly significant correlations between the calf responses and the air temperature with the relative humidity and between each other as well.

It was evident that the animals had better comfort in the asbestos roofed barn. It is suggested that the colder walls and roof at night and early morning (22.00 and 06.00 hrs.) act as heat sinks which facilitates heat dissipation from animals’ body that was accumulated.