As Plains states’ temperatures go from a mild, wet spring to the dead of summer within a week, there are growing reports of cattle stress and even deaths.
Reports of death losses can be hard to track down since no one wants to own up to the losses, figuring such an admission, no matter how unavoidable, could make it hard to get new business. But as temperatures and humidity mount, it’s almost inevitable that at least some death losses are occurring.
THE SCIENCE WEIGHS IN
The Iowa State University College of Veterinary Medicine has an article on its web site titled “Heat Stress In Beef Cattle,” by ISU Beef Extension Veterinarian Dr. Grant Dewell, that addresses the issue more scientifically.
“Typically, pastured cattle are not as susceptible to heat stress as feedlot cattle,” Dewell said. They can seek shade, water and air movement to cool themselves.
But radiant heat from a dirt or concrete surface is increased for feedlot cattle, he said. At temperatures above 80 degrees Fahrenheit, cattle endure physiologic stress, and while cattle at this temperature are not at risk of dying, they will have an increased maintenance requirement to cope.
Compared to other animals, cattle cannot dissipate their heat load very effectively, Dewell said. Cattle do not sweat a great deal and rely on respiration to cool themselves.
Compounding that is the fermentation process within the rumen, which generates additional heat that cattle need to dissipate, he said. Since cattle do not dissipate heat well, they must dissipate heat at night when it is cooler.
Another problem for cattle is solar radiation and wind speed, which can affect heat load of cattle.
During extreme weather conditions with insufficient environmental cooling at night, cattle will not be able to disperse body heat, Dewell said.
A feedlot manager said feedlot overcrowding and lack of adequate water access can affect wind speed and prevent cattle from all the overnight cooling that is possible. And, even then, if the wind stops on hot, humid days, the heat load can build quickly, sometimes to lethal levels.
Cattle should not be worked during times of extreme heat and only early in morning when it is hot, Dewell said. Cattle’s core temperature peaks two hours after peak environmental temperature, and it takes at least six hours for cattle to dissipate their heat load.
One final note: heavy, dark-colored cattle cannot handle heat stress as well as younger, lighter-colored cattle, Dewell said. Typically, proportionality more black hided cattle die during heat waves then other hide colors.
CATTLE, BEEF RECAP
The USDA reported formula and contract base prices for live FOB steers and heifers this week ranged from $135.00 to $143.15 per cwt, compared with last week’s range of $134.15 to $142.43. FOB dressed steers, and heifers went for $214.64 to $217.29 per cwt, versus $212.70 to $218.64.
The USDA choice cutout Tuesday was down $1.10 per cwt at $269.44, while select was down $0.63 at $246.82. The choice/select spread narrowed to $22.62 from $23.09 with 99 loads of fabricated product and 36 loads of trimmings and grinds sold into the spot market.
The USDA reported that basis bids for corn from feeders in the Southern Plains were unchanged at $1.90 to $2.00 a bushel over the Jul futures and for southwest Kansas were steady at even the Jul, which settled at $7.68 1/4 a bushel, down $0.01.
No live cattle delivery intentions were posted Tuesday.
The CME Feeder Cattle Index for the seven days ended Monday was $160.11 per cwt down $0.11. This compares with Tuesday’s Aug contract settlement of $171.30, down $0.02.