By Cox, Neil R. and Matthews, Lindsay R. and Schütz, Karin E., Applied Animal Behaviour Science, 2008
Research Paper Web Link / URL:
http://www.sciencedirect.com/science/article/pii/S016815910800110X
http://www.sciencedirect.com/science/article/pii/S016815910800110X
Description
Provision of shade to dairy cattle in summer can alleviate negative effects of heat stress. The aim of this study was to investigate the relative importance of shade to lactating dairy cows in different ambient weather conditions in summer. The motivation to use shade was compared to the motivation to lie down after exposure to different levels of lying deprivation. Twelve cows were tested nine times in a test arena for 1 h where, under a range of ambient environmental conditions, they were given an opportunity to either stand or lie down in a non-shaded area or to stand in shade (shade cloth blocking 80% of ambient solar radiation), when previously deprived of lying for 0, 3, or 12 h. It was predicted that cows would increase their relative choice to rest as the duration of lying deprivation increased and that this choice would be affected by ambient temperature. Every time the cow entered a new area in the arena, and changed positions between standing and lying, the time was noted. Weather variables measured were ambient air temperature, relative humidity and solar radiation. All weather variables were divided into three categories (low, medium and high) and analysed separately. Cows deprived of lying for 12 h increased their time spent standing in shade with increasing ambient air temperature (<25 °C, 0.7 min/h; 25–30 °C, 3.5 min/h; >30 °C, 18.9 min/h; S.E.D.: 13.0, P = 0.021) and all treatment groups spent less time standing in the shade when the relative humidity was high (<40%, 11.3 min; 40–55%, 19.5 min; >55%, 1.9 min/h; S.E.D.: 4.8, P < 0.001). Cows deprived of lying for 12 h spent less time lying when solar radiation levels were high (<500 W/m2, 11.8 min; 500–825 W/m2, 24.6 min; >825 W/m2, 0 min/h; S.E.D.: 16.9, P = 0.006). In conclusion, the results suggest that the requirement for shade during hot days (high ambient air temperature) is relatively high, since dairy cows chose to stand in shade at high air temperature rather than lying after experiencing 12 h of lying deprivation.
Provision of shade to dairy cattle in summer can alleviate negative effects of heat stress. The aim of this study was to investigate the relative importance of shade to lactating dairy cows in different ambient weather conditions in summer. The motivation to use shade was compared to the motivation to lie down after exposure to different levels of lying deprivation. Twelve cows were tested nine times in a test arena for 1 h where, under a range of ambient environmental conditions, they were given an opportunity to either stand or lie down in a non-shaded area or to stand in shade (shade cloth blocking 80% of ambient solar radiation), when previously deprived of lying for 0, 3, or 12 h. It was predicted that cows would increase their relative choice to rest as the duration of lying deprivation increased and that this choice would be affected by ambient temperature. Every time the cow entered a new area in the arena, and changed positions between standing and lying, the time was noted. Weather variables measured were ambient air temperature, relative humidity and solar radiation. All weather variables were divided into three categories (low, medium and high) and analysed separately. Cows deprived of lying for 12 h increased their time spent standing in shade with increasing ambient air temperature (<25 °C, 0.7 min/h; 25–30 °C, 3.5 min/h; >30 °C, 18.9 min/h; S.E.D.: 13.0, P = 0.021) and all treatment groups spent less time standing in the shade when the relative humidity was high (<40%, 11.3 min; 40–55%, 19.5 min; >55%, 1.9 min/h; S.E.D.: 4.8, P < 0.001). Cows deprived of lying for 12 h spent less time lying when solar radiation levels were high (<500 W/m2, 11.8 min; 500–825 W/m2, 24.6 min; >825 W/m2, 0 min/h; S.E.D.: 16.9, P = 0.006). In conclusion, the results suggest that the requirement for shade during hot days (high ambient air temperature) is relatively high, since dairy cows chose to stand in shade at high air temperature rather than lying after experiencing 12 h of lying deprivation.
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