As I write this, I'm bidding farewell to another 111 degree day in Arizona. Yesterday, I walked a 4,000 cow dry lot dairy from one end to the other observing cows. The cows on my client's dairy were doing fine under the shades with little apparent signs of heat stress.
That's more than I could say for myself. I couldn't wait to get back to the air conditioned office. The cows I saw today also looked good; evidence of what effective heat abatement can do in this climate. Production is down a little, but certainly not what you would expect under these conditions.
Last month at the American Dairy Science meetings in Indianapolis, I attended a talk by Dr. John Smith from Kansas State on the effect of cooling systems on body temperature in dairy cattle. In one study, John measured the impact of feedline soakers on vaginal temperature of cows during hot weather and showed a significant drop of almost 1 degree Fahrenheit due to the cooling system.
Someone in the audience asked if this was a big enough drop in body temperature do be of any economic significance or health advantage considering the cost of the system. Having seen what heat stress can do to cows (and me) my thought is that any drop in body temperature is worth it. Surviving a summer, especially in the South and Southwest without a significant decrease in production, reproduction or cow health will certainly reap benefits throughout the year.
I was on another dairy last week that was building new barns and shades after a storm had demolished the old facilities. It was extremely hot and unfortunately the cows had no shade, fans or water for cooling during reconstruction. Milk was down about 20 lbs/cow. The cows were visually stressed, panting and had little interest in the feed that had been put out for them. The new barns would be ready in a day or two, but I'm sure most of the cows would not recover the lost production during their current lactation.
I'm convinced that every dollar invested in cow cooling and comfort is worth it. I'll take a 1 degree drop in body temperature anytime.
Reference: J.Dairy Sci. Vol. 91, E-Suppl. 1 p.131.
Rick Lunquist is an independent nutrition and management consultant based in Duluth, Minn. You can contact him at email@example.com.