COMPARISON OF CALF HOUSING TYPES AND TYMPANIC TEMPERATURE RHYTHMS IN HOLSTEIN CALVES

During fall, 30 Holstein calves were randomly assigned to three housin g treatments from birth to weaning: conventional wooden hutches, enclo sed molded polyethylene domes, and thermomolded opaque polymer hutches with ridge-top ventilation systems. The wooden and polymer hutches ha d outdoor pens. Fifteen calves, 5 in each housing type, were fitted wi th portable data loggers to record ambient (calf microclimate) and tym panic temperatures. Additional data collected included weekly girth, B W, and feed intake; blood samples were collected within 24 h of birth and at weaning (8 wk); and behavioral observations were made at 1, 4, and 7 wk of age. Polyethylene domes had the warmest microclimate, foll owed by wooden and polymer hutches. Feed intake, growth measurements, blood physiology, and behavior were unaffected by housing type. Diurna l tympanic temperature rhythms of neonatal dairy calves in this study were monophasic: maximums were at 1200 to 1700 h, and minimums were at 0600 to 0900 h. Computed fractal dimensions of tympanic temperature b y week indicated a gradual diminishing of stress as the calves became older and acclimated to their environment. This objective characteriza tion provides a basis for further evaluation of physiological stress a nd a means of improving environmental management.