By John F. Grimes, OSU Extension Beef Coordinator
So just what are the “Dog Days” of summer? According to Wikipedia, the “Dog Days” are the hottest, most sultry days of summer. Based on our latitude in the northern hemisphere, these days usually fall between early July and early September. The name comes from the ancient belief that Sirius, also called the Dog Star, in close proximity to the sun was responsible for the hot weather. I wasn’t sure of the actual definition of the term “Dog Days of Summer” so now we can all consider ourselves more informed!
All jokes aside, the weather that we are experiencing in Ohio this week truly qualifies as the “Dog Days of Summer.” Actual temperatures are well into the nineties and heat indexes are very high. The current weather conditions can provide high levels to humans, crops, and cattle alike. Producers need to consider their daily management practices in order to minimize the stress resulting from current weather patterns to their beef herd.
Many nutritionists will tell you that the most important component of a diet is the one that is lacking or missing. While all nutrients are important, one that we must monitor under the current conditions is water. Regardless if the primary water source for your herd is private (ponds, springs, or streams) or from a city or county supplier, we must insure that all animals have a plentiful supply of high quality water in order to maintain good health and achieve profitable performance.
What are the daily water requirements for beef cattle? You may be surprised. The minimum requirement of cattle for water reflects the amount needed for growth (body and/or fetal), lactation, and to replace what is lost by excretion in urine, feces, or sweat. These water needs are influenced by environmental temperature, the production class of beef (lactating cow, dry cow, bull, etc.), and weight. Moisture content of the feed consumed will influence an animal’s water requirement.
According to Dr. Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist, daily water requirements for the non-lactating beef animal will run from 0.75 to 1.5 gallons per 100 pounds body weight or 6 to 12 % of their body weight. Lactating cows nursing calves may consume 18% of their body weight. Therefore a typical 1200 pound spring calving cow will require about 216 pounds of water each hot summer day. Since a gallon of water weighs approximately 8 pounds, this equates to 27 gallons of water per cow per day (not counting the calf). A University of Georgia publication indicates that an animal’s water requirements double when temperature increases from 50 to 95 degrees F. These facts confirm the importance of a plentiful supply of high quality water under the current high temperatures.
While water is a primary focus when discussing beef cattle stress during hot weather, there are additional management practices that can help to reduce stress. Consider the following practices:
Shade: Regardless if it is manufactured (barns, netting, etc.) or from a natural source (trees), shade is extremely important for animal comfort. In order to be effective, there needs to be 20-40 square feet of shade per animal and the height of the shade structure should be greater than eight feet tall to allow for sufficient air movement.
Feeding Patterns: Heat production from feed intake peaks four to six hours after feeding. Heat production from cattle fed in the morning will peak in the middle of the day when temperatures are high. Consider feeding cattle after daytime high temperatures have been reached. This may help avoid highly variable intake patterns that can be seen in hot weather.
Cattle Handling: Avoid working cattle that are susceptible to heat stress during times of elevated temperatures typically seen from mid-morning until early evening.
Fly Control: Effective fly control can help to reduce heat stress. Biting flies tend to cause cattle to bunch up which reduces cooling.