From Freshening to Dry Off, Implement These Tips to Help Keep Cows Cool

 

Summer is just around the corner and, with it, heat stress. According to a 2019 Foundation for Food and Agriculture Research study, the U.S. dairy industry experiences $1.5 billion in losses annually due to heat stress. With afternoon humidity of 60-70 percent and temperatures at 75-77°F, cows may already begin to experience the effects of heat stress.

When animals experience heat stress, typical outcomes include the following:

• Decreased dry matter intake
• Decreased milk production
• Decreased conception rates

Heat stress impacts more than just the milking herd. Between calves, dry cows, and milking cows, dairy producers should implement a whole-herd heat stress solution to limit those impacts.

Milking Cows: When it comes to lactating cows, heat stress has the greatest short-term impact. Use a two-fold approach to help cows survive and potentially thrive during the heat and humidity of summer. One strategy is to use mechanical cooling by providing fans and soakers in areas where cows congregate. Another strategy is to cool cows internally. Higher temperatures can negatively affect milk production and milk fat yield, due in large part to heat stress-induced pH decreases in the rumen and leaky gut. Although it is vital to provide proper heat abatement strategies, there are also feeding strategies that may assist in decreasing performance lost. By incorporating an immune support feed additive, you could help promote gut health, immune strength, and overall wellness. Healthy cows perform better, and a healthy gut can help cows manage the heat. Ultimately, this can result in greater profitability on the farm. Consult with your nutritionist about what ration changes might be appropriate for warmer temperatures, including the addition of products to optimize rumen health.

Another beneficial idea is to conduct a TMR audit. This is a systematic approach to measuring the operational efficiency of a dairy’s feeding system. Today’s TMR audits can detect inconsistencies in the ration and help identify other feed-related management opportunities. The ability to deliver a consistent diet day after day, week after week, and month after month is an important goal for nutritionists and producers because ration consistency directly affects the operation’s bottom line. Consistent diets support a healthy rumen, which allows other body processes to function well so the cow experiences optimal health, reproduction, and milk production.

Dry Cows: The impact of heat stress on milking herds is well-known, but the impact on dry cows – those in the last two months of pregnancy – is less understood. One of the most important things to know is the impact of heat stress doubles with dry cows. It can also affect the calf in utero. When a dry cow experiences heat stress, the body temperature of the unborn calf increases. This alters the calf’s metabolism and gene expression, which can lead to smaller calves being born, along with affecting the calf’s health and performance well beyond birth. Cooling your dry cow and their fetal calf can lead to a positive impact on production. Research from the University of Florida demonstrated that cows cooled during the dry period:

• Produced 8-14 pounds more milk per day over approximately 280 days
• Maintained better body weight, likely allowing for better performance post-calving

Heat Stress Top Five Checklist

When it comes to heat stress, remember these top five checklists to help your herds have a better chance of staying healthy and productive.

1. Pushup feed: It is quite common for feed intake to decrease during hotter months. When cows eat less this can lead to decreased milk production. To keep their appetites up, make sure they have constant access to fresh feed. This is extremely important during overnight hours.
2. Holding pen ventilation and cooling: Producers can use the respiratory rate of an animal to indicate heat stress. Anything above 80 breaths per minute is a sign of advanced heat stress. When it comes to the holding pen, you want a wind speed of 10+ mph.
3. Pressure on feed bunk soaker lines: Pressure on soaker lines should be 15 to 20 psi (pounds per square inch). If you see mist in the air the water pressure is too high. The height of soakers needs to be five to six feet off cow platforms. Have a controller set for nozzles to run a certain amount of time on and off. It’s recommended, at 70 degrees have the nozzle running for one minute on and twelve minutes off. For 82 degrees, have the nozzle running for one minute on and four minutes off.
4. Check wind speed: Wind speed should be 7+ mph anywhere cows congregate such as feed bunks, stalls, and holding pens.
5. Housing: Make sure every cow has a clean and useable stall. Cows make the most milk when they’re laying down; so, we want their housing as comfortable as possible.

Heat stress is inevitable. It can have a devastating impact on your animals, and not just those lactating. Between calves, dry cows, and milking cows, implement a whole-herd process for reducing the impact of heat stress, helping your herd stay happy, healthy, and productive.