Heat, Humidity Can Be Disastrous For Nebraska Livestock

Take precautionary steps to manage heat stress, in the feedlot and also at county fair shows.

Published on: Jul 31, 2013

Nebraska's livestock, following a mild, rainy spring, now face the consequences of heat and humidity.

Heat stress is hard on cattle and other livestock, especially when combined with high humidity and low wind speeds, according to Lindsay Chichester, University of Nebraska-Lincoln Extension educator. "Heat stress can reduce feed intake, weight gain, reproductive efficiency and milk production, while increasing susceptibility to diseases."

Signs of heat stress can include animals bunching, seeking shade, and panting, slobbering or excessive salivation, foaming around the mouth, open mouth breathing, lack of coordination and trembling, Chichester says.

IN THE SHADE: More feedlots have installed shade devices to protect cattle from heat.
IN THE SHADE: More feedlots have installed shade devices to protect cattle from heat.

If these symptoms are observed, handlers should assume the animal is suffering from too much heat and immediately try to minimize the stress to the animal, especially by reducing handling or movement of the animal, she recommends. Previous health of individual animals is an important risk factor, as animals with past health problems will be more affected by heat stress than animals with no prior health problems. These animals will generally be the first to exhibit signs of heat stress and be the most severely affected.

Chichester also offers several recommendations about animals shown at upcoming county fairs in Nebraska.

If the heat index is above 100 degrees, animals can tolerate it if shade is available and/or wind speed is at least 10 miles per hour, so show animals should be provided shade and/or moving air via fans, she says.

If the index gets above 110 degrees, animals will stressed regardless of wind speed.  "Show animals should be in the shade with fans, especially market ready animals, and have plenty of access to water," according to Chichester. "If a heat index above 110 is predicted, livestock shows should be completed by noon. In addition, livestock that need to be moved or transported should be out of the facilities by early morning but certainly by noon, if possible."

If the heat index is above 115 degrees, avoid moving or handling market ready animals. Livestock show rings should be shaded with fans and misters; the show staff should consider postponing the show due to excessive heat.

If the heat index is above 120 degrees, no activity should occur for animals or humans.

During the heat of summer, livestock management musts include providing: shade, ventilation and air flow, clean and cool water, wetting, cool water drench and sprinklers or hoses. Shade can be provided by trees, buildings or other sunshades.

In addition, the temperature can be lowered by spraying cool water on the roof and walls of buildings where the animals are being housed. Improved ventilation can be provided by fans or opening windows on a breezy day. Sunshades should be high enough off the ground (10 feet or more) to allow for adequate air movement.

Chichester stresses that if you are wetting down cattle, the droplet size should be large enough to wet the skin, not just the air. "A small droplet size will usually just wet the hair creating more humidity for the animal, thus not helping at all."

During times of heat stress, animals should not be subjected to too much activity, including movement or transportation.

More information is available at http://beef.unl.edu.