The ladies like it cool… Starting today (Part 2)

By Rod Martin
It’s the end of May and that means heat abatement strategies should be in place on your dairy.  A good method to review your cooling strategy is the 3-M approach:  mechanical considerations, metabolic considerations and management considerations.

I discussed several mechanical considerations in my last post, including shade, airflow and water access.  Click here to review that information.  Now let’s discuss the metabolic and management considerations.

Metabolic considerations

• Energy:  Diet adjustments can reduce the effects of heat stress on the dairy cow.  Heat stress increases respiration rates and sweating as the cow attempts to lower her body temperature.  These responses increase the maintenance requirements of the cow by as much as 35 percent while significantly reducing feed intake, resulting fewer nutrients and energy available for milk production.  Supplementing extra energy in the form of a high-quality bypass fat is an excellent way to increase energy intake while maintaining effective fiber during periods of heat stress.
• Electrolytes:  Maintaining a normal electrolyte balance during heat stress is another concern.  Adding extra potassium in the form of potassium carbonate is recommended in order to achieve at least 1.5 percent dietary potassium level.  Extra sodium and magnesium are also recommended to maintain electrolyte balance.
• Protein:  Evaluate total dietary protein levels and protein fractions to make sure excess protein is not being fed.
• Other additives:  Many feed additives claim increased performance during periods of heat stress.  These include yeast products, probiotics, bypass niacin and Amaferm® to name a few.  Work closely with your nutrition consultant to determine if these products have an economical role on your dairy.

Management considerations
As with anything, the devil is in the details.  Proactive attention to management details is critical for maintaining productive efficiency during periods of heat stress.  Consider the following management strategies to counteract the negative effects of heat stress.

• Fan Maintenance:  Poor fan maintenance can reduce efficiency by more than 40 percent.  Check, clean and perform maintenance on all fans before each cooling season.
• Sprinklers:  Be sure sprinkler are working correctly and soaking the cows’ backs to achieve the evaporative cooling effect.  Optimal cooling takes place with 4- to 6-mph continuous wind speed when combined with sprinkler systems.  In addition, consider placing a sprinkler system in the exit lanes from the parlor.
• Drinking water:  Keep water troughs clean and check water flow rates for increased water intakes.  Consider water along the exit lane from the parlor.  Cows will consume a significant portion of their daily water intake in exit lanes.
• Shade:  Provide shade over all feed lanes. Don’t forget about the dry cows and prefresh cows since high dry matter intakes are especially important for transition success.  Fans are also recommended in combination with the shade.
• Feeding:  During periods of heat stress, feed multiple times per day to keep feed fresh and stimulate the cows to move to the feedbunk to maximize feed intake.  Feeding during the cooler parts of the day also stimulates feed intake.  Adding a TMR preservative, such as Bunklife, is recommended to keep feed from heating.
• Foot health:  Pay close attention to laying-down behavior and make sure standing time is minimized during periods of heat stress.  Excessive standing time results in significant foot issues that show up two to three months later.  Maintain a sound foot trimming schedule during the summer months to minimize residual foot issues.
• Reproduction:  Reproductive efficiency is significantly affected by heat stress.  Incorporate management and nutritional strategies to minimize body condition loss during heat stress.  Pay close attention to the calving and fresh cow pens to reduce metritis.  Stay on task for your breeding protocols to maximize pregnancy rate.
• Labor:  During times of heat stress, be cognizant of the effects on employees and their ability to follow through on their day-to-day tasks.  Have extra labor available or current labor organized to ensure heat stress management details are getting done.

Heat stress in dairy cattle results in a significant economic loss if not proactively managed correctly.  Reduced milk yield is the most obvious effect, but reduced reproductive performance, poor foot health, increased metabolic issues and higher cull rates are also significant contributors to reduced profitability.

With milk prices at an all-time high, the payback for improved heat abatement strategies on your dairy is pretty significant.  Work with your consultant and other key industry leaders to evaluate your heat abatement program on your dairy.  There are a lot of resources and information for you to take advantage of in order to minimize the negative effects of heat stress.

About the author: Rod Martin is a dairy specialist and a member of the Vita Plus dairy technical services team.  He grew up on his family’s diversified livestock farm in southwest Wisconsin and attended the University of Wisconsin-Madison, where he earned a bachelor’s degree in agricultural education and animal science, and a master’s degree in animal nutrition.  He has 24 years of experience in consulting with Midwest dairy operations.