Experts provide tips to manage heat stress and pests in sheep flocks this summer
A hot, dry summer is in full swing across the West, and experts are reminding sheep producers seasonal heat and insect pressure can have significant impacts on flock health.
With the potential to affect everything from feed intake and weight gain to immune function and reproductive performance, proactive management is key to minimizing loss and keeping sheep healthy and productive throughout the hottest months of the year.
Mitigating heat stress
According to multiple Extension publications from services in Nebraska, Missouri, Ohio and Alabama, heat stress occurs when animals cannot dissipate enough heat to maintain their body temperature.
Although outdoor temperature is the most obvious component affecting heat stress, other factors like humidity, sunlight exposure, wind speed and water availability can also influence body temperature regulation.
In a June 18 newsletter, the Idaho Sheep and Goat Health Board (ISGHB) notes signs of heat stress include increased panting and respiration, drooling, lethargy, reduced grazing activity, going off of feed altogether and congregating in shade or around water sources.
“Producers should adopt a multidisciplinary approach to lessen the impact of high heat and humidity,” states University of Missouri Small Ruminant Specialist David Brown, further encouraging producers to provide adequate shade and ensure sheep have access to cool, clean water at all times.
Brown notes, on average, sheep and goats will drink one to two gallons of water a day and lactating animals will consume even more. He cites research conducted at the University of Maryland showing sheep drink 12 times more water when it’s dry and the temperature exceeds 100 degrees Fahrenheit.
Many livestock specialists also recommend handling and transporting animals during early morning or later evening hours when temperatures are lower and moving animals to barns, temporary structures or other shaded areas with ample air circulation during heat waves.
Shearing sheep in the spring is also critical, as sheep with heavy fleeces or too little wool are less tolerable to hot, summer temperatures.
“Spring shearing allows for enough wool growth prior to summer for heat to escape the sheep’s body,” explains ISGHB. “Shearing just before a heat wave can cause unintended stress like sunburn and decreased ability to regulate body temperature effectively.”
Brown echoes this sentiment, citing studies showing sheep with a one-inch fleece tolerate higher temperatures than sheep with less wool.
Reducing pest pressure
As temperatures climb, insect populations do too.
Flies, gnats, ticks and other biting insects can create constant irritation and cause sheep to spend less time grazing and more time fighting flies.
ISGHB notes, “Heat and insects exemplify each other’s effects. As temperatures rise, insect populations explode.”
The board goes on to note several fly species can pose challenges for sheep producers.
“House flies can carry diseases, stable flies and black biting flies leave behind painful bites and blowflies can cause fly strike in areas of soiled wool or open wounds,” ISGHB states.
To combat this, experts recommend integrated pest management, including a combination of sanitation, grazing management and chemical controls.
Removing manure accumulation, maintaining clean feeding and watering areas and eliminating standing water can help reduce insect breeding sites. Producers may also utilize approved sprays, pour-ons, dips and other pesticides, and experts recommend rotating products to avoid resistance.
Additionally, experts say rotational grazing systems can also help disrupt insect life cycles and reduce pasture overcrowding, and the American Consortium for Small Ruminant Parasite Control recommends producers incorporate fecal egg counts and FAMACHA scoring into their parasite management programs.
Nutrition and breeding considerations
Stress from heat and insects can have lasting impacts long after the summer is over.
According to ISGHB, heat-stressed animals will experience reduced feed consumption, lower average daily gains, compromised immune function and increased susceptibility for disease.
“Summer heat stress and insect presence can impact lamb health during vital growth stages,” the board writes. “During the summer, maximize nutrient density while minimizing digestive heat. Feed growing lambs during the coolest parts of the day; ensure easy access to cool, fresh water and electrolytes and reduce high-fiber forages as they generate excess body heat.”
Researchers have also documented reproductive impacts from prolonged heat and insect stress.
According to University of Minnesota Extension, elevated temperatures may reduce sperm production and libido in rams while negatively affecting embryo survival and fetal development in ewes.
To prepare for fall breeding season, producers should ensure rams are in good body condition, are free of parasites and receive adequate nutrition leading up to and after the breeding season.
Producers may also consider reviewing a flushing plan for their ewes prior to breeding.
“This may look like movement to high-quality pasture or supplementation with a high-energy diet,” ISGHB says. “Ensure selenium is always offered or provide a complete mineral mix.”
“Each operation is run in its own unique way. These are a few considerations while navigating the hot and ‘buggy’ season ahead,” the board continues. “External factors may be out of our control, but weathering the effects is always possible with preparation.”
Hannah Bugas is the managing editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.
