By Russ Quinn
DTN Staff Reporter
OMAHA (DTN) -- The high temperatures gripping most of the Midwest are tough on both man and beast. While humans can retreat inside to air-conditioned comfort, livestock cannot.
Cattle producers, both cow-calf and feedlot, need to be proactive to lessen heat stress in cattle. Providing more water and shade, increasing airflow, and allowing cattle to access sprinklers can all lessen the effects of high temperatures and humidity.
LOTS OF HEAT
The Midwest's current heat wave is forecast to spread across the central and eastern U.S. in the coming days, according to the National Weather Service (NWS). High temperatures in the 100s Fahrenheit are expected for the southern and central High Plains, with 90s widespread further to the east.
"With temperatures in the 90s, high dew points will create dangerous heat indices and excessive heat warnings and watches as well as advisories are in effect for much of the Plains, Mississippi and Ohio valleys and into the Eastern Seaboard," NWS reported. "Overnight low temperatures will not provide much relief, with values in the mid-to upper 70s to even 80 degrees."
DTN Senior Ag Meteorologist Bryce Anderson said the current spell of intense heat rivals the very hot year of 2012. The heat is expected to last through July 20.
The good news for most of the central part of the U.S. is the forecast for the coming weeks is for lower temperatures, he said.
"The forecast for August is for near- to below-normal temperatures," Anderson said. "So, it looks like this heat wave may be a solo act for the season."
The USDA-Agricultural Research Service (ARS) and the National Oceanic and Atmospheric Administration (NOAA) combined to create heat stress maps for livestock. These maps can be found at https://www.ars.usda.gov/….
Much of the middle of the country is in yellow (alert), orange (danger) and red (emergency) designations through July 20. Over the weekend and into next week much of the region is back to mainly yellow.
MANAGING HEAT STRESS
DTN has written about managing heat stress in cattle operations in the past. Read one of those articles here https://www.dtnpf.com/….
The University of Nebraska-Lincoln (UNL) Extension has a Heat Stress Resources webpage (https://bqa.unl.edu/…). The site includes several links to a heat stress mitigation webinar, USDA Heat Stress Monitor information and a beef cattle temperature humidity chart (https://bqa.unl.edu/…).
There are several key points to reducing heat stress, according to UNL Extension.
Cattle should have a steady supply of abundant fresh water. For every 1,000 pounds of weight, cattle can require at least 20 gallons of water per day when the ambient temperature is above 80 degrees.
Cattle producers, especially in the feedlot setting, need to provide sprinklers and shade to cattle in pens.
Use sprinklers with large droplet size to keep the pen floor and mounds cool for cattle to rest on. Research has found shading reduces the solar heat load by 5 to 10 degrees for cattle resting under it, according to UNL.
Additional items to lessen heat stress in cattle include allowing airflow to cattle and processing cattle early in the morning.
Move cattle away from windbreaks and allow as much airflow through the pens as possible during high heat and humidity. If cattle need to be handled, do it in the early morning before 10 a.m., the report said.
A publication from North Dakota State University (https://www.ag.ndsu.edu/…) suggests cattle producers develop a three-step plan for managing heat stress.
Step one: Identify animals that are more susceptible to heat stress. This would be feedlot cattle, very old or young animals and animals with dark hides. Research has shown cattle with dark hides have a two-degree higher core body temperature than those with lighter-colored hides, the report stated.
Step two: Develop an action plan for heat stress. This plan should include such items previously listed as more water, shade, air movement and working cattle in the early morning.
Step three: Know when to intervene. Cattle are in danger from heat exposure when the heat index is 75 F or greater for a 72-hour period and if the heat index during a 48-hour period is no lower than 79 F during the day. In addition, cattle are also in danger when the heat index is no lower than 75 F during the night and the daytime heat index reaches 84 F or higher for two consecutive days.
Russ Quinn can be reached at firstname.lastname@example.org
Follow him on Twitter @RussQuinnDTN
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