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Effect of spatial orientation and shade on internal environment of a wooden 3-calf hutch
The objective of this study was to determine internal environments of California-style 3-calf hutches according to a combination of spatial orientation and shade. During mid-autumn at the University of Arizona’s Campus Agricultural Center, Tucson, 8 California-style (3 cubicles/hutch) were designated to 1 of 2 treatments: exposure to direct sunlight (DS) or placement underneath a drylot shade structure (NDS). Hutches within each group were oriented to 1 of 4 directions: north, south, east, and west. Hutches were equipped with 6 temperature/relative humidity data loggers (2 loggers/cubicle) evenly placed at 41 cm above the slatted wood flooring and 41 cm from the sides of the cubicle. For 4 d, each hutch was rotated clockwise once every 24-h period and before daylight hours so that each hutch was exposed to all 4 directions at least once. Ambient condition data were analyzed as a complete randomized block design with hutch as the experimental unit. Overall, DS hutches had a greater average temperature-humidity index (THI) (62.7 versus 61.5 ± 0.17; P < 0.01) compared to NDS hutches. However, DS hutches had greater 24-h range (P < 0.01) for THI (56.1-69.2 versus 57.4-65.7 ± 0.19), ambient temperature (26.3-13.4 versus 22.5-14.6 ± 0.18°C), and relative humidity (24.8-42.3 versus 27.5-39.9 ± 0.37%) compared to NDS hutches. A 24-h THI range of 60.5 (north-facing NDS) to 63.6 (east-facing DS) with a temperature range of 17.7 (north-facing DS) to 20.6°C (east-facing DS) was observed. Highest THI (P < 0.01) was recorded for all treatments except west-facing NDS during 1200 to 1800 h (THI > 70) compared to other 6-h periods (0000 to 0600, 0600 to 1200, 1800 to 0000 h). South-facing DS hutches recorded the greatest THI range (51.5 – 75.7; P < 0.01), while west-facing NDS hutches had the least THI range (57.3 – 64.5; P < 0.01). Grid mapping of daytime and nighttime THI for each treatment showed THI uniformity within each hutch was dependent on both orientation and shade. Results indicate shaded wooden 3-calf hutches are kept at a cooler and less variable environment compared to unshaded hutches during a mid-autumn, southwestern climate. Also, a 13-point THI difference during a 24-h period can be observed within a hutch exposed to direct sunlight.
Keywords: calf hutch, internal environment, spatial orientation