Heat Stress on Cattle: What August Costs

An animal lost to heat stress costs more this year than it would have a few years back, with the national herd at its smallest in 75 years and prices to match. The signs of heat stress are simple to read once you know them, and the fixes cost almost nothing next to that.

Texas A&M AgriLife Extension specialists Dr. Ron Gill and Dr. Jason Smith lay out a clear progression: increased respiration first, then open-mouth panting, drooling, reduced feed intake, and lethargy. Their guidance is direct about the worst sign: if an animal starts open-mouth panting while being worked, release it immediately and call a veterinarian.

AgriLife's guidance is built around the Temperature Humidity Index, a formula that combines air temperature and relative humidity into a single number. A THI below 72 means no stress, 72 to 79 is mild, 80 to 89 is moderate, and above 89 is considered severe. Real-time, localized THI readings are available through tools like the ThermalAid website, which is worth bookmarking during the hottest stretch of the year rather than estimating by feel.

The fixes are mostly about timing and access, not equipment. Work cattle early morning or late evening, and avoid handling them during peak afternoon heat. Make sure water is available in holding pens and during transport, not just in the home pasture. AgriLife recommends 20 to 40 square feet of shade per animal where it's available. Water needs roughly double in extreme heat, from about 1 gallon per 100 pounds of body weight in cool weather to nearly 2 gallons per 100 pounds when it's hot, and lactating cows need close to double that again. Young calves, heavier animals, and any cattle already sick are the most vulnerable and worth checking first.

CattleFax's 2026 outlook puts the average fed steer price at $224 per hundredweight, holding close to 2025 levels, with the national cattle herd at its smallest since 1951. CattleFax has also flagged the New World Screwworm situation and Mexican feeder cattle import status as separate risk factors ranchers are watching this year. Those two things, heat stress and screwworm, aren't connected in anything published so far. They're simply two things worth staying ahead of in the same season, for different reasons.

The fix for heat stress is mostly free: shade, timing, and water somebody bothered to check. It only costs something once it gets ignored.

AgriLife Today, How to Prevent Heat Stress in Cattle (June 25, 2026): https://agrilifetoday.tamu.edu/2026/06/25/how-to-prevent-heat-stress-in-cattle/

High Plains Journal, How to Prevent Heat Stress in Cattle (AgriLife content, June 29, 2026): https://hpj.com/2026/06/29/how-to-prevent-heat-stress-in-cattle/

Texas A&M Department of Animal Science, Recognizing and Avoiding Heat Stress in Cattle: https://animalscience.tamu.edu/department-updates/recognizing-and-avoiding-heat-stress-in-cattle/

Texas Animal Health Commission, New World Screwworm: https://www.tahc.texas.gov/emergency/nws.html

NCBA, CattleFax Outlook Signals Cattle Cycle Turning as Strong Demand Meets Tight Supplies in 2026: https://www.ncba.org/news-media/news/details/46676/cattlefax-outlook-signals-cattle-cycle-turning-as-strong-demand-meets-tight-supplies-in-2026

Texas Farm Bureau, CattleFax Forecasts Continued Strong Demand, High Prices: https://texasfarmbureau.org/cattlefax-forecasts-continued-strong-demand-high-prices/

USDA APHIS, USDA Confirms Presence of New World Screwworm in the United States: https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-presence-new-world-screwworm-united-states

MyRGV, Veterinarian Shortage Poses Screwworm Vulnerability in South Texas (July 3, 2026): https://myrgv.com/local-news/2026/07/03/veterinarian-shortage-poses-screwworm-vulnerability-in-south-texas/