By Dr. Elliot Block, Senior Manager, Technology, Arm & Hammer Animal Nutrition
The stress associated with summer heat can have negative, lasting effects on herd performance, health and profitability. How you prepare cows for heat stress and the adjustments made to management and feeding practices can help your herd successfully navigate this challenging time period.
Utilize these eight tips to minimize the negative impacts of heat stress and maintain performance throughout the hot summer months:
1. Change feeding habits. Slowly shift feeding schedules so fresh feed is offered early in the morning and/or late in the evening—the coolest times of the day. Feeding when temperatures are highest can reduce dry matter intake (DMI) and cause ration heating, which can cause additional decline in DMI. Alongside changes in the feeding schedule, increase frequency of bunk push out/clean out, particularly if feed line soakers are adding moisture to existing feed in bunks.
2. Rework the ration. While some decline in DMI is anticipated in hot weather, the severity of the drop may call for ration reformulation to increase nutrient density. This allows the cows to still receive necessary nutrients for production and maintenance needs through fewer pounds of feed.
· Feed additional rumen inert fat to increase ration energy density without increasing heat of rumen fermentation.
· Increase bypass protein levels to account for the decline in dry matter intake.
· Work with your nutritionist to ensure the ration delivers the nutrients needed for peak performance in hot weather.
3. Increase ration potassium. Potassium is the main mineral in sweat and as temperatures rise, cows lose more potassium through sweating, panting and urination. Beyond the potassium lost during normal milk production, this nutrient becomes even more critical in hot weather. Ensure your herd receives a high-quality potassium source that is protected from overheating to raise potassium levels to 1.7% of ration dry matter and ration DCAD to +35 to +45 meq/100g ration dry matter and maintain DMI, while meeting increasing nutrient demands.
4. Ensure water availability. Cows’ water needs increase significantly during heat stress, making it absolutely critical that clean water is available at all times. To maintain parlor flow, have waterers available in the exit lane rather than in the parlor entrance or in the holding pen and be certain that water pressure is sufficient to deliver this essential nutrient.
5. Reduce stocking density. Overstocking in hot weather can generate too much heat to dissipate. Keep stocking densities at 100 percent with 30 inches of feedbunk space per cow to encourage DMI while keeping cows cool and comfortable.
6. Offer shaded areas. Shade should be available for all groups of cows to minimize the direct contact with the sun. In dry lots, the ideal orientation is north/south at a minimum of 14 feet tall to provide the most coverage.
7. Properly ventilate facilities. Depending on your situation and location, either natural ventilation or mechanical ventilation (fans) may be used. The goal is to keep the air moving as much as possible. The cooling system should begin to work at 68 degrees Fahrenheit to keep the cow’s internal temperatures low.
8. Add soakers for evaporative cooling. The purpose of soakers is to soak the cow to her skin and allow for evaporative cooling using fans. Soaking a cow that is already wet will provide little additional cooling. The more wet/dry cycles per hour, the more cooling that can be achieved. The wetting frequency will increase as the temperature climbs. Here are some general guidelines:
· 70º F (21º C) = Every 15 minutes
· 80º F (27º C) = Every 10 minutes
· 90º F (32º C) = Every 5 minutes