by Nigel Key and Stacy Sneeringer
Highlights:
In 2010, heat stress is estimated to have lowered annual milk production for the average dairy by about $39,000, totaling $1.2 billion in lost production for the entire U.S. dairy sector.
Climate change is likely to increase average daily temperatures and the frequency of heat waves to varying degrees across the country, which could increase heat stress and lower milk production.
Additional heat stress from climate change is expected to lower milk production for the average dairy by only 0.60 to 1.35 percent in 2030 relative to what it would have been in the absence of climate change with today’s technology.
In many parts of the United States, climate change is likely to result in higher average temperatures, hotter daily maximum temperatures, and more frequent heat waves, which could increase heat stress for livestock. Heat stress can reduce meat and milk production and lower animal reproduction rates. Livestock producers can mitigate heat stress with shade structures, cooling systems, or altered feed mixes, but these methods increase production and capital costs. Dairy cows are particularly sensitive to heat stress; higher temperatures lower milk output and milk quality.
A recent ERS study quantifies the costs of climate change-induced heat stress to the U.S. dairy industry. The study used operation-level economic data coupled with climate data to estimate how the local thermal environment affects milk output. This information is used to estimate the potential decline in milk production in 2030 resulting from climate change-induced heat stress. The results indicate modest heat stress-related production declines over the next 20 years, with the largest declines occurring in the South.
Heat Stress Lowers Dairy Productivity
Every animal has an optimal range of temperatures in which it can maintain a normal body temperature without altering its physiological functions or behavior. Above these temperatures, an animal may experience heat stress resulting in changes in respiration rate, heart rate, sweating, blood chemistry, hormones, metabolism, and behavior. Animals under heat stress generally increase their water intake and reduce their feed intake.
https://www.ers.usda.gov/amber-waves/2014/november/greater-heat-stress-from-climate-change-could-lower-dairy-productivity/#:~:text=Depending%20on%20the%20climate%20model,%245%2C000%20(at%202010%20prices).
