Summer Is Off With A Large Bang!


in cattle, it is important to observe your live- stock frequently and take necessary precau- tions. Producers should take


I


DR. TERESA L. STECKLER SIMPSON, ILL.


t’s early July in southern Illinois and thus the weather has


been almost unbear- able.


Temperatures


have been hovering 90+ F with oppressive hu- midity. With the heat index hovering around 100 F it becomes very important for livestock to have access to shade and plenty of clean, cool water. I also want to re- mind farmers to be very careful that they can overheat easily as well. Searing temperatures


are hard on livestock – and humans. However, the combination of high temperatures and hu- midity can create an es- pecially


dangerous


situation for livestock. High temperatures and humidity can negatively impact breeding effi- ciency, milk production, feed intake, weight gains, and sometimes cause death. It is im- portant for producers to know what factors can contribute


to heat


stress. Cattle prefer cooler


temperatures with little to no humidity. Danger- ous situations can de- velop


when


temperatures approach 85 F with high humidity and as temperatures soar so does the poten- tial danger to livestock. Numerous


factors


contribute cattle’s sus- ceptibility


to heat


stress. Basically, these factors can be catego- rized as environmental or animal-related. Envi- ronmental factors in- clude


ambient


temperature, solar radi- ation, humidity, wind speed, soil moisture, and overnight tempera- tures. Animal-related factors


include origin of the cat- tle, acclimation to the environment,


age,


health, hair coat, nutri- tion, and genetics. Ge- netics influences hair color and temperament. In addition to knowing


those factors that can contribute to heat stress


precautions when hot and humid weather is forecasted. Here are some tips to minimize heat stress in cattle: Make sure cows have


access to cool, clean drinking water. A jump in outside temperatures of 10-15 degrees F can increase total water re- quirements by 2.5 times. The cool water will help maintain inter- nal temperatures closer to normal. However, in- creased water con- sumption will increase urine excretion. This results in an increased loss of certain minerals, such as sodium (a part of salt), potassium, and magnesium.


Provide


free choice trace min- eral salt in a location where animals will con- sume it. Loose salt will be more readily con- sumed than block salt. Move the animals’


feeding time to late af- ternoon or evening. This will allow rumen fer- mentation to take place during the cooler night temperatures, and it will increase lung ca- pacity for the cattle dur- ing the hotter daytime temperatures. Normal digestive processes cre- ate heat in cattle. This body heat reaches a maximum several hours after the meal is con- sumed. When feeding cattle in the morning of high-heat-stress days, producers may be matching peak environ- mental


temperature


with peak body temper- ature from digestion. Al- tering feed deliveries accordingly can avoid some potential addi- tional heat from diges- tion. Remember that high


quality forage produces less heat of fermenta- tion than low quality forage. Avoid feeding ex- cess protein during pe- riods of heat stress. The excess nitrogen sup- plied by the protein must be detoxified and prepared for excretion (via urine) which is a biochemical pathway that demands large amounts of energy. Ensure cattle have ac-


cess to shade; trees, buildings or sunshades. Solar radiation from sunny, clear skies con- tributes to body temper-


ature in cattle. Black- hided cattle in the same pens with white-hided cattle will have internal body temperatures sev- eral degrees hotter than the white-hided cattle. Pay attention to long-


and short-term weather forecasts, have a copy of the temperature humid- ity index chart readily available, or just down- load the application (“app”). Determine the potential risk threshold and be prepared, even if the risk is several index units away. Additional solar heat, lack of air movement and heavy fat cover all can lead to dis- astrous effects of heat stress. The Heat Stress Forecast


Maps


(www.ars.usda.gov/) can provide a general guideline for expected cattle heat stress. The maps account for pre- dicted ambient temper- ature, humidity, wind speed, and cloud cover. Last year USDA's Agri- cultural Research Serv- ice (ARS) has launched a new smartphone app that forecasts condi- tions triggering heat stress in cattle. The app is available at both Google Play and the App Store. Remember if you must


move cattle on a hot day, take them slowly. If there are calves and you are rotating to a new pasture, cows will often travel at a speed faster than their calves. If the pasture is very far away, the calves may become overheated trying to stay with the cows. If the herd is not slowed down or made to stop, the calves may become overheated to the point of dying. There are several


signs of heat stress in cattle and it is impor- tant to recognize these as soon as possible. Signs of heat stress in- clude bunching (in the shade if it’s available), slobbering, high respi- ratory rates (panting), open mouth breathing, lack of coordination, and trembling. If you see these signs, assume the cattle have high heat loads, and mini- mize the stress immedi- ately, but handle the animals gently to avoid increasing their stress even more. Be prepared for heat


stress. As hot weather approaches, monitor your cows frequently


CONTINUED ON PAGE 16 July 17, 2020 www.mafg.net / MidAmerica Farmer Grower • 7


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