Cow Cooling: Don’t Forget About your Dry Cows!

As the heat of summer continues to beat down, the problem of heat abatement for cows is still prevalent. Realistically, all cow groups on the farm should be cooled in the summer by way of sprinkler systems, fans or a combination of both. However, in reality, limited-budgets often play a part in the amount of cow cooling that occurs.

Many dairies across the country have excellent cow cooling systems in place for their lactating cows. However, research done by Texas A&M University has shown that dry cows are often more sensitive to heat stress than lactating cows. Heat stress prior to calving reduces the levels of thyroid hormones and placental estrogen which affects the growth of the udder and the unborn calf.

Further study has shown that when cows are cooled during the last 3 months of pregnancy, calf birth weights have increased up to 10%. In heifers especially, heat stress also has affect on the quality of colostrum. Colostrum from first-calf heifers, experiencing heat stress, showed significantly lower levels of immunoglobulin’s, protein, fat and lactose that are crucial for calf survival.

A study conducted by the University of California-Davis at a 3,000 cow dairy in central California, showed that dry cows that were cooled with sprinklers, fans, and shades were projected to give nearly 186 pounds more milk during the first 60 days of lactation. Doing so produced economic returns of approximately $2,131 per year.

When making decisions about cow cooling, the first cow group that should be considered is the close-up cows, animals that are within 3 weeks of calving. During this time, the dry matter intake is critical to ensure a successful upcoming lactation. When cows are panting and sweating, feed intake is reduced, as is immune system function and the amount of time that cow spends lying down.

Once the close-up cows are adequately cooled, cows that are fresh or in the early stages of their lactation should be next on the list. These cows are headed for peak lactation stages and, according to research done in Kansas, every one pound of milk lost in the peak lactation stages results in 250 pounds of milk production lost for the entire lactation.

Finally, cows in mid to late lactation should be cooled. These cows have passed their peak production period and are slowly setting up to be dried off again, so, while keeping this group cool and comfortable is important, it is not as pressing as the other 2 groups.

Remember, the cheapest way you can provide heat abatement for your cows is to provide them with more than enough fresh water. Cows will drink almost 1/3 more water in the summer than when the temperatures are cooler.

In the hustle and bustle and heat of summer, don’t forget about your dry cows. Make them your #1 priority, after all getting them off to the best start possible means more economic returns for you!

Research taken from the Texas Agricultural Extension Service, The Kansas State University Extension Service, and the Journal of Dairy Science (June 2006).

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Posted Jun 27th

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