Shade-Seeking Behavior of Rotationally-Grazed Cows and Calves in a Moderate Climate

Abstract

In moderate climates there is some concern that the benefits of providing beef cattle shade on pasture may not outweigh the associated costs. Congregating in shade can result in manure accumulation and reduced pasture fertility. There is also a perception among producers that providing shade may reduce the time that cattle spend grazing. The objectives of this study were to quantify the shadeseeking behavior of beef cattle on pasture in relation to environmental conditions and to determine the effects of providing shade on the amount of time spent grazing in a moderate climate. Three beef cowcalf pairs were held on each of twelve 1.2-ha fields. Each field was divided into 8 rotationally grazed paddocks with a central lane-way leading to a water trough. On half of the fields a structure providing 80% shade was located in the lane-way. Cattle behavior was sampled for activity and location every 10 minutes during 6-h periods on 24 days from May-Dec 1998. Air temperature, relative humidity and black globe temperature were recorded once each hour during the observation periods. From the values for black globe temperature and relative humidity, the Black Globe Humidity Index (BGHI) was calculated. Overall, cows with shade spent (mean ± SEM) 18.0 ± 1.4% of time in shade. The amount of time cows spent in shade was significantly related to air temperature (P<0.05) and BGHI (P< 0.05). Cows without shade spent significantly more time at the water trough (P<0.05) and more time out on pasture (P<0.05) than cows with shade. Time spent at the water trough was significantly related to BGHI for cows without shade (P 0.10). However, time spent grazing was not affected by treatment (P>0.10). These data indicate that cattle will spend short periods of time in the shade even on cool days, but that the amount of shade-seeking is related to environmental conditions. Cattle without shade spend more time congregating at the water trough on hot days. Although cattle with shade spend less time out on pasture overall, this does not result in reduced grazing time.