LINCOLN, Neb. — With temperatures hitting the triple digits, cattle producers
need to take steps to ward off heat stress in their herds, a University of
Nebraska-Lincoln beef specialist said.
Cattle can
begin to experience some level of heat stress when the heat index approaches 80
degrees, with most cattle being severely stressed when the heat index exceeds
100 degrees, said Terry Mader, beef specialist at UNL's Haskell Agricultural
Laboratory near Concord.
Also, when early morning temperatures and/or the heat indices are in the
mid-70s, chances are cattle did not adequately cool down at night, and feedlot
managers should be prepared to provide as much relief to cattle as possible
during the day.
Water is probably
the best way to dissipate heat, Mader said. Cattle
normally take in about five to eight gallons of water per day. However, when
temperatures rise, that amount can double or even triple.
"It's
important to have plenty of available water," he said. "When there is
competition for water, it creates problems because the dominant animals will
occupy waterer space and not allow other animals access."
If cattle
are crowding around the watering trough, add more waterer capacity or move some
of the animals to pens that will give them adequate access to water, Mader
said.
In an
emergency, cattle can be sprayed with water to cool them down. However, once
producers do that, they need to repeat or continue spraying until the heat
subsides. Spraying cattle with water will allow the animal to rapidly dissipate
heat through evaporative cooling processes but this may limit the animal's
ability to adapt to the heat.
If the pen
surface is dry, wetting the pen also will provide relief to confined animals.
It is always beneficial to start the wetting or cooling process in the morning
before the cattle get too hot.
Another suggested heat stress mitigation tactic is to use bedding to decrease
surface temperatures animals are exposed to, Mader said. Generally it's thought
bedding is for insulation against cold stress. However, straw can aid in
breaking up or diffusing the solar heat load that often contributes to heating
up dry, bare ground. The degree bedding is effective in doing this is unknown.
However, if used, it is suggested bedding be placed in the pen early in the
morning when the ground has cooled; otherwise, heat will be trapped in the pen
surface.
Also, wetting the bedding would allow for additional cooling to occur
when the animal uses it.
Producers should avoid handling cattle when it's hot and never after 10 a.m.
Cattle body temperatures can rise an additional 0.5 to 3.5 degrees during
handling.
Cattle yards
also should be free of any structures that restrict airflow. Cutting down
vegetation around pens and moving cattle away from windbreaks can all help.
Building earth mounds in pens also can increase airflow by preventing cattle
from bunching together.
Other heat stress mitigation strategies include:
providing shade, controlling biting flies and other parasites, keeping very
current on cattle marketings and being mindful of heat effects on personnel as
well.
For more
information about managing heat stress in feedlots, visit www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=1448.
