Effect of Different Spray Flow Rates on the Cooling of Free-stall Dairy Cows in Summer
The aim of the experiment was to investigate the effects of different spraying flow rate treatments on the environment and cooling effect of loose lactating cows in the summer barn.The experiment was designed as a one-way trial,in which 40 lactating dairy cows were randomly divided into four groups of 10 cows each,with 0 L/min,0.4 L/min,1.2 L/min and 4 L/min of intelligent spray cooling treatment.The experimental period was 5 days with loose feeding management,providing the same diet,free drinking water,environmental indicators of summer barn,cow production performance,physiological indicators,behavioral parameters were measured at regular intervals,in order to analyze the effects of different spraying flow rate cooling treatments on the summer environment of the semi-open barn and the cooling effect of lactating cows.The results showed that,compared with 0.4 L/min,the 1.2 L/min and 4 L/min treatments significantly increased the environmental indexes of the barn's feeding aisle(P<0.05),alleviated the respiratory rate of cows,the increase in rectal temperature,the partial immune response of cows caused by heat stress.It also increased lactation and feed intake,reduced the number of times cows enter the spraying zone,and the effects of 1.2 L/min and 4 L/min are similar.So it is recommended to use the spraying cooling flow rate of 1.2 L/min from the viewpoints of water conservation,emission reduction and cooling effect.
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