CLIMATE CHANGE COULD LEAD TO LESS MILK PRODUCTION

Rising temperatures caused by climate change possibly could lead to a decline in milk production across the United States, according to new research presented today at the Conference on Climate Change. The findings suggest dairy cows in the southern U.S. will be affected the most.

Researchers at the University of Washington found that the decline in milk production due to climate change will vary across the United States, since there are significant differences in humidity and how much the temperature swings between night and day across the country. For instance, the humidity and hot nights make the Southeast the most unfriendly place in the country for dairy cows.

The study combined high-resolution climate data and county-level dairy industry data with a method for figuring out how weather affects milk production. The result is a more detailed report than previous studies and includes a county-by-county assessment of the impact climate change will have on Holstein milk production in the United States through 2080.

“Using U.S. Department of Agriculture statistics, if you look at milk production in the Southeast versus the Northwest, it’s very different," the researcher said. “It’s reasonable to assume that some of that is due to the inhospitable environment for cows in the Southeast."

The researchers found in Tillamook, Ore., where the climate is humid and the nighttime temperature doesn’t change much, milk production begins to drop at a much lower temperature than in the dry Arizona climate. Tillamook cows become less productive starting at around 15 C, or 59 F, while those in Maricopa, Ariz., start making less milk at around 25 C, or 77 F. In humid Okeechobee, Fla., cows become less productive at about the same temperature but losses increase at a much faster rate than in Arizona.

Data also revealed dairy farmers are already clustering in the most comfortable areas for cows, such as the cool coastal counties of Washington state. But the outlook isn’t good for areas across the southern U.S. where cows are already less productive in the heat of the summer.

“Perhaps most significantly, those regions that are currently experiencing the greatest losses are also the most susceptible: they are projected to be impacted the most by climate change," they said.

While the researchers project that dairy production averaged across the U.S. will be about 6% lower in the 2080s than at the start of the century, other factors are likely to actually boost milk production.

“Management practices and breeding are on track to double milk production in Holsteins in the next 30 or 50 years," they said. “So while a 6% drop is not negligible, it’s small compared to other positive influences."