By Theopolis Waters
KANSAS CITY (B)--Late-summer record-breaking heat in parts of the U.S. Midwest and southern Plains is interrupting hog producers' marketing cycles because of slowed weight gains. The scorching temperatures also are responsible for short-term sterility in boars that could ultimately lead to fewer sows bred than expected. Heat has already been linked to death losses of small pigs in western areas of the Midwest as well as some market-ready hogs while in transit to slaughtering plants.
Almost all U.S. hog production takes place within confinement buildings outfitted with high-technology cooling systems, which in the summer can drop indoor temperatures approximately 10 degrees below outside conditions. But, it only takes a short time in extreme temperatures to push up inside temperatures and cause hog conception problems and marketing headaches for producers.
Extended bouts of hot weather cause hogs to consume less feed, which curbs weight gains. Heat stress also can create reproductive glitches in sows and boars as well as contribute to death rates in hogs, from farrowing to marketing.
Missouri's string of 90- and 100-degree-plus readings since early August will have an impact on hog reproduction, especially for boars, said Ron Plain, University of Missouri agricultural economist. Long periods of high temperatures can promote semi-sterility in boars lasting for a month or so.
This will cause sows not to become pregnant, and come back into heat three weeks later. This can lead to fewer numbers of litters born in the winter than expected. Missouri was sixth in hog marketings last year, with 8.0 million head shipped, valued at $452.2 million, according to the U.S. Department of Agriculture.
Oklahoma producers are using whatever evaporative cooling means they have at their disposal to keep hogs as comfortable as possible. Hog farmers are struggling and hoping for a break in temperatures, said Scott Carter, assistant professor of animal science with Oklahoma State University.
One of the most visible impacts from the heat is slow weight gains due to less feed intake, which is creating a backlog in "flows," or hog cycles. Some pigs are being forced marketed at lighter weights to make room for new arrivals, said Carter. The state was seventh last year with shipments of more than 5.7 million hogs worth $303 million.
Kansas producers are reeling from a string of triple-digit afternoon highs, said Jim Nelssen, Kansas State University swine specialist. Anything consistently above 85 degrees Fahrenheit coupled with humidity ushers in heat-stress and a drop in production.
Despite cooling systems, sows become agitated and can injure piglets.
Producers can modify confinement unit environments with the use of drip systems, but that does very little to offset this extreme heat, Nelssen said.
Under present conditions, pigs and small hogs fare better than those that are nearer market weight, he said. Hogs weighing 250 to 300 pounds develop a layer of fat that retains heat and can lead to the larger animals dying from heat stress. USDA ranked Kansas 10th last year with 2.5 million head marketed worth $198.9 million.
Texas, more noted for raising cattle than hogs, is surviving 60-plus days without significant rain along with scalding temperatures. But hog production is on the rise, said Jodi Sterle, Extension swine specialist with Texas A&M University.
Slight decreases in production, litter size, feed efficiency and average daily weight gains were anticipated. However, hog growing conditions in the Texas Panhandle--where most of the state's hogs are reared--is conducive for pork production because of low humidity. Hogs there are also confined and comforted by cool cell technology, which basically pulls air through running water, Sterle explained.
Typically during the summer, nationwide, there is about a 0.2% increase in sows "crushing" their small pigs because the heat causes the sows to get up and down more often. Texas marketed just more than 1.2 million hogs in 1999 worth a total gross market value of $89.6 million, and ranked 17th, according to USDA data.