37
Effect of heat retaining covers on calf hutch temperature during cold weather
Previous studies have demonstrated that reflective hutch covers reduce temperatures inside calf hutches, but the efficacy of reflective covers during cold weather has yet to be determined. This study determined the effect of heat retaining covers on the internal air temperature of polyethylene calf hutches. Treatments on farm 1 included an aluminized 3.0 mil black LDPE (reflective) and a 4.0 mil LDPE (non-reflective) cover. Farm 2 included only the reflective cover. The covers fit over the top of the hutch, overlaying the top, sides, and back; leaving the front of the hutch exposed. The study was conducted for a 29 d period from December to January at two dairy farms located near Plainview, Texas. At both farms, five uncovered (control) hutches and five hutches from each treatment were fitted with duplicate temperature loggers that recorded temperature every 30 min for the duration of the study. At the start of the study, hutches housed calves 2-4 d in age. The coldest 2-h period was identified and treatment effects were determined with ANOVA and LSD. At farm 1 the reflective covers were warmer than control hutches by 1.5° C (P<.01) and the non-reflective covers were warmer than the control by 1.2° C (P<.01). At farm 2 the reflective covers were warmer than the control by 1.5° C (P<.05). This period was also characterized by very little wind. When the coldest ambient temperature each day throughout the study was identified, covers were not significantly different than the control (P>.05) on both farms. This emphasizes the importance of the wind influencing air temperature in the hutch. However, there was still a consistent trend on both farms in which the reflective cover was warmer by 1.16° C on farm 1 and 1.5° C on farm 2. In conclusion, the reflective cover was more effective and the hutch covers had the greatest effect on internal air temperature in low wind. The heat retaining covers in this study can be expected to improve the comfort of calves in cold temperatures, however the biological significance of these covers is currently being investigated.
Keywords: dairy calf, hutch, cold stress