Innovative Dairy Cow Cooling Technologies Tested at UC Davis

Adapted by Alycia Drwencke and Cassandra Tucker – Department of Animal Science, Theresa Pistochini – Western Cooling Efficiency Center

With this summer having been one of the hottest in California history, the term heat stress is all too familiar around dairy farms. As the ambient temperature climbs, cows experience increased stress as they break down feed and produce milk, which both generate heat and make it difficult for them to handle the weather. Heat stress will lead to drooling, open mouth breathing, increased respiration rates, decreased fertility and milk production, and in severe cases, mortality.

Often, California dairy farms use soakers over the feed bunk and fans over the freestalls to keep cows cool. However, this method of cooling can lead to an average water use of 40 gallons of water, per cow, every day, which raises concerns about using this limited resource for cooling cows (values based on 10 dairy farms in Tresoldi et al., California Agriculture, in press). That amount of water use can be a substantial portion of input costs and can still result in yearly production losses that surpass $800 million across the nation. With the California dairy industry bringing in $6.23 billion in cash receipts in 2015, and housing 1 in 5 dairy cows in the country, the economic losses caused by heat stress are extensive.

Above Picture - Cows line up to receive cooling from innovative direct evaporative coolers at the UC Davis dairy

Two new and innovative methods of cooling are currently being evaluated at the University of California, Davis. These technologies are designed to reduce water use by up to 86% and energy use by up to 38%, which could potentially result in sizeable economic and resource savings for the dairy industry. The two technologies were tested in comparison to the traditional soaker and fan combination at the university dairy this summer. The researchers are now in the process of analyzing data to determine which technology was the most effective and efficient when cooling the cows. One of these technologies will be tested on a commercial scale in the Central Valley, next summer. Water and energy use, as well as production, will be quantified in this test to evaluate cost effectiveness.

One technology utilizes a Sub-Wet Bulb Evaporative Chiller (SWEC) to cool water that flows through mats buried ~4 inches beneath the sand beds, where cows spend an average of 10-14 hours per day. Heat dissipates from the cow, into the sand and mats, where the heated water is returned to the chiller. The water is then cooled again by the SWEC, and flows back to the mats, to remove more heat from the cows lying in the beds.

The second technology uses targeted, direct evaporative cooling and cloth ducts to blow cooled air on to the cows. These ducts and high efficiency evaporative coolers were placed both at the feed bunk and above the freestalls.

A combination of respiration rates, body temperature, cow behavior, milk yield, weather, energy and water use data are all being evaluated to determine the effectiveness and efficiency of each cooling method. This research is well timed with the extensive heat California has been experiencing and could lead to important changes and economic savings for the dairy industry in the near future.

Link to PDF Version: Innovative Dairy Cow Colling Technologies Tested at UC Davis