Friend T H, Haberman J A, Binion W R
Department of Animal Science, Texas A&M University, 2471 TAMU, College Station, TX, 77843, USA,
Int J Biometeorol. 2014 Dec;58(10):2165-8. doi: 10.1007/s00484-014-0810-z. Epub 2014 Mar 12.
Polyethylene hutches are a popular method of housing dairy calves from 0 to 60 or more days of age, although these hutches get hot when in full sun. This study characterized the relative differences in the ability of four different types of radiant barriers to reduce black-globe temperature within these hutches. Treatments included three different types of covers (two types of laminates (Cadpak P and Cadpak ESD) and an aluminized 3.0-mil white low-density polyethylene (LDPE)) and a reflective paint (LO/MIT-1). The reflective covers were 1.8 × 3 m finished size, and covered the top and sides of the hutch down to 0.15 m above the ground, leaving the front and back exposed. The LO/MIT-1 paint covered the entire sides and roof of the hutch. Two 24-h trials 1 week apart were conducted during relatively hot and clear days in early August. Black-globe temperatures were recorded in duplicate and averaged at 20-min intervals using blackened table tennis balls mounted 0.3 m above the floor in the center of each hutch. Ambient temperature (shade) during the hottest 2-h period for both trials averaged 39.9 °C while the uncovered control averaged 41.1 °C, and LO/MIT-1 averaged 39.9 °C; both of which were significantly higher (P < 0.01) than the Cadpak P (38.9 °C), Cadpak ESD (38.6 °C), and aluminized LDPE (38.7 °C). During periods of high solar radiation, the hutches with covers had lowest black-globe temperatures followed by hutches painted with reflective paint, while control hutches had the highest temperature.
聚乙烯犊牛栏是饲养0至60日龄或更大日龄奶牛犊的一种常用方法，不过这些犊牛栏在阳光直射下会变得很热。本研究描述了四种不同类型的辐射屏障在降低这些犊牛栏内黑球温度能力方面的相对差异。处理方式包括三种不同类型的覆盖物（两种类型的层压板（Cadpak P和Cadpak ESD）以及一种镀铝的3.0密耳白色低密度聚乙烯（LDPE））和一种反光漆（LO/MIT - 1）。反光覆盖物成品尺寸为1.8×3米，覆盖犊牛栏的顶部和侧面直至离地面0.15米处，前后保持暴露。LO/MIT - 1漆覆盖犊牛栏的整个侧面和顶部。在8月初相对炎热且晴朗的日子里，相隔1周进行了两次为期24小时的试验。使用放置在每个犊牛栏中心地面上方0.3米处的涂黑乒乓球，以20分钟为间隔重复记录黑球温度并求平均值。两次试验中最热的2小时期间的环境温度（阴凉处）平均为39.9℃，未覆盖的对照组平均为41.1℃，LO/MIT - 1平均为39.9℃；这两者均显著高于Cadpak P（38.9℃）、Cadpak ESD（38.6℃）和镀铝LDPE（38.7℃）（P < 0.01）。在高太阳辐射期间，有覆盖物的犊牛栏黑球温度最低，其次是涂有反光漆的犊牛栏，而对照犊牛栏温度最高。
