FL AIP Steer

This steer is experiencing heat stress.

In the U.S., economic losses from heat stress in fed cattle were estimated more than $365 million over the summer heat season. That estimate is from 17 years ago. Currently, it is probably closer to $500 million considering the value of harvest ready cattle in 2003 was $75-$80/cwt vs $115-$120/cwt today.

Economic Losses with Heat Stress

In 2003 there was a comprehensive research project that examined the economic loses of heat stress on U.S. livestock industries. The research examined the dairy industry, beef cows, finishing cattle, swine and poultry. The project demonstrated in excess of $2.4 billion in annual losses across all industries. If heat abatement strategies were employed it reduced the annual losses to $1.7 billion – regardless, a big number, and undoubtedly bigger today. We have applied the equation models to current-day projected heat stress financial losses to fed cattle.


The research demonstrated three measurable financial losses presented due to heat stress in fed cattle per year. We apply the finishing model to the heat stress season. The research uses various integrals and functions of the Temperature-Humidity Index (THI) in the models. These losses are described as:

• Loss of dry matter intake

• Loss of Daily Gain

• Death Loss

Lost revenues to the Feedyard

Commercial feedlots are in the business of selling feed to their cattle feeder clients. The feed margins generated (markup) offset the costs associated with feeds and feeding cattle. Some feedyards use feed markup and daily yardage fees, and some just use a feed markup and no yardage fee to cover overhead. Using todays average feed dry matter and feed cost there is a dry matter intake loss of greater than 65 lbs of dry matter intake during a heat season. This equates to approximately $12/hd.

Impact: In a 45,000 hd yard, with all cattle present in the heat stress season, with no abatement or mitigation of heat stress, this model equates to more than $540,000 in projected reduced feed sales. If the average markup were 15%, the Gross Margin loss is more than $82,000.

Implementing a feedyard heat stress strategy to maintain feed intake makes economic sense when feed markups are used to cover overhead. This is especially true if the feedyard can reduce this lost revenue by 50% or more.


Lost Revenue to the Cattle Feeder

Cattle feeding profitability can be elusive and at times, very high risk. The cattle feeder looks to the commercial feedyard to maintain optimum performance, health programs, and assist with risk management practices. The cattle feeder relies on the expertise within the feedyard management, pen riders, and professional staff to implement these programs for the welfare of their cattle. The loss of daily gain in the research model is predicted to be more than 19 lbs and with the added death loss using today’s cattle value per pound equates to more than $27/head loss during the heat season.

Impact: For a pen of 120 head during the heat stress season with no abatement or mitigation heat stress strategy has an additional potential average loss of more than $3200 for the pen. Implementing a feedyard heat stress strategy to maintain performance and reduced death loss makes economic sense for the benefit of the cattle feeder. This is especially true if the cattle feeder can recover this lost revenue by 50% or more.

Why is Heat Stress so Destructive with Long-lasting Effects?

There is a lot of excellent scientific literature on the physiology of heat stress in cattle. It is not my intent to go into this research, but to present a simple 3-step schematic summary (Figure 1).

The damage that is done to major organs from an over-reactive immune response during a heat stress episode, especially the lung and liver, can have irreversible effects on health and performance.

Heat Stress Strategy

There ar multiple factors in putting together a heat stress strategy. Figure 2 illustrates many of the important aspects in managing heat stress. One of the more important factors is the environment, including water quality and availability, pen space, sprinklers and shade when possible. Feed Additives is another and is often overlooked. But the right feed additive may hold the key to a successful heat stress strategy.

Scott Crain, D.V.M. is Technical Services Veterinarian for OMNI Animal Health. Robert T. Coffey, D.V.M. is Director, Veriprime Research Division.