Heat Stress Problem
Daily life in diary cow sheds is affected by excessive heat. Both the cow’s normal metabolism and the conversion of nutrients into milk generate heat. A cow becomes heat stressed when she produces more heat than her body can passively dissipate to the surrounding environment. That situations are very often even in Poland’s climate, because optimal ambient temperature for dairy cow is in range 8-16°C and body reactions of thermal regulation start appear in temperature of 20°C. In connection with high humidity of air, heat dissipation becomes limited. A heat stressed cow increases her sweating and respiration rates to transfer more heat to the environment through evaporation. Also, cow increases standing time, because this position gives her more convenient conditions for air flow and heat transfer through convection.
To reduce metabolic heat, cow reduces her dry matter intake, at the same time cow’s energy demand is increasing, which results in reduction of milk yield by as much 10 to 25%. In addition, she starts to select her pasture which leads not only to unbalanced microelement management and summer acidosis but also lower milk protein and fat content. Heat stress is also responsible for reduced cow’s immunity, and hormone changes, resulting in reproductive problems.
Heat-stress episodes caused by variable climate can be especially hard for cows to cope with because it can take weeks for a cow to fully adapt to heat-stress conditions, leading to important economic consequence.
Conventional Cooling Methods
To reduce the risk of heat stress, dairy producers can start operating in several directions:
- provide shade,
- introduce measures that will artificially lower the temperature and augment the air velocity using a variety of sprinkler, mister and fan systems.
Nevertheless, under hot and humid conditions, shading and fans alone are insufficient to alleviate heat stress Furthermore, fans consume electricity and sprinkler, or mister systems consume large amounts of water. Cooling cow sheds is very complex, expensive and not well established, especially when taking into account the immense thermal losses from their structure.
RadMat Cooling System
RadMAT project is being created in response to demand for cattle cooling. At this moment convective cooling is not effective enough, especially above ambient temperature 25°C, when this type of heat transfer becomes negligible. This leads to a system, which increases heat dissipation from the surface of a cow’s body. That is the reason why novel cooling system is based on conductive heat transfer.
Proposed system connects commercially available waterbeds with cooling system. In that concept, cold water circulates through the mattress in a closed system. Due to temperature gradient between circulating water and animal’s body, a heat transfer process occurs from the laying down cow to the cooled surface, alleviates the heat stress in the animal.
Goals Of The Project
Goals of the RadMAT Project are presented on the video below: