Page 17 - MWC 8-6-20s
P. 17
The Midwest Cattleman · August 6, 2020 · P17
UNDERSTAND AND LESSEN HEAT
STRESS WHEN WORKING CATTLE
By Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist
Here they come! Those
four little words that Oklaho-
ma cattle producers despise
in the summertime: “High
Pressure Heat Dome”. Un-
derstanding and avoiding
heat stress in cattle can be
a valuable management tool
for summertime. Most areas
of Oklahoma have 10 or more
days each year above 100 de-
grees and 70 or more days with
high temperatures above 90
degrees Fahrenheit. (Source:
1997 Oklahoma Climatologi-
cal Survey). This means that
most cow calf operations will
be working cattle on days
when heat stress to cattle is
likely.
Cattle have an upper crit-
ical temperature approxi- duced pregnancy rates in heat hot day. loaded with cattle will have
mately 20 degrees cooler than stressed cattle. 2. Cattle that must be very little if any air move-
humans. When humans are Research data has been handled during hot weath- ment. Cattle will gain heat
a little uncomfortable at 80 reported by Dr. Mader at the er should spend less than 30 constantly while they are in
degrees and feel hot at 90 de- University of Nebraska re- minutes in the working facil-
grees, cattle may well be in search station near Concord, ity. Drylot pens and corrals continued on page 25
the danger zone for extreme Nebraska. He found that mov-
heat stress. Humidity is an ing yearling cattle just a small
additional stressor that inten- distance (2000 feet) during
sifies the heat by making body mild summer temperatures
heat dissipation more diffi- (80 degrees F.) could change
cult. Knowledge of daily body the core body temperature Located 45 mi. SE of Kansas City, Mo on 58 Hwy. east at
temperature fluctuations and by as much as 1.4 degrees F. Modern Kingsville Livestock Auction Center at Kingsville, MO
the impact of handling cattle This indicates that body tem-
on body temperature can be peratures of excited, stressed
valuable at this time of year. cattle being worked in hotter
Oklahoma State Universi- temperatures could rise to Make Plans To Attend Our Next
ty research with rumen tem- dangerous levels.
perature boluses has shown Increases in core body tem- Special Cow & Bull Sale
that the core body tempera- peratures have been shown to
ture of beef cows peaks at 2 to reduce conception rates at the
5 hours after the highest day- time of artificial insemination - Saturday, August 15th -
time temperature (Pye, Boeh- and reduced embryo survival
mer, and Wettemann. 2011 and viability for at least 14 11:00 am
ASAS Midwest Abstracts days following breeding. If
Page 104; Abstract 285). On cattle working procedures are
a hot spring/summer day the still necessary for breeding or
highest daytime temperature for health purposes during the
is often late afternoon. There- heat of summer, following a On-Line Bidding available at
fore, the peak body tempera- few commonsense guidelines
ture of cattle will occur at 6 may lessen the impact of heat: CATTLE USA.com
PM to 11 PM. In this study, 1. During hot weather, cat-
average 4 pm ambient tem- tle should be worked before
perature was 93 degrees F., 8:00 am, if possible. Certain-
core body temperature was ly, all cattle working must be All Consigners & Buyers Welcome
102.2 F. At 7 pm the ambient complete by about 10:00 am. Call 816-597-3331 Office
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temperature increased to 103 down, they may need at least 816-258-3421 • 816-716-9288 • 816-878-5229
F. Elevated core body tem- 6 hours of night cooling before
peratures have been implicat- enough heat is dissipated to Website: www.anstineauctions.com • email: kingsville@earthlink.net
ed from other research in re- cool down from an extremely
