There are days when finding bright spots is hard because the beef industry is in a bit of a tough spot. Things will work out, but, for today, it is tough.
For the short term, heat, humidity and windless days are bad news for cattle.
Actually, for most living things, heat and humidity are not good. The confounding effects of direct and immediate health issues with cattle, along with long-term feed availability issues, have even the well-seasoned producer worried.
The problem is not new, but, unlike last year, the temperatures continue to reach for triple digits and the scarcity of seasonal rains across the U.S. is seriously impacting feed reserves.
In the short term, heat impacts cattle performance because cooling down, or the dissipation of body heat, is critical for survival. High temperatures do not allow for a good mechanism to effectively dissipate a cow's internal body heat production. The body needs to function at a preset temperature range, so internal alerts sound loud and clear when that temperature gets out of the acceptable range. Death will ensue unless a normal body temperature range is restored.
Recent high heat and humidity, plus relatively calm days, trigger overheating.
Although the common thought is that this is a feedlot problem because of the confinement and proximity of the cattle to each other, heat exhaustion knows no boundaries. For instance, cattle have a typical rectal temperature of 101 F. As the ambient temperature and humidity go up and the wind goes down, the ability of an individual to remove excess body heat goes down.
A heat stress index has been calculated to determine what alarms should go off and is well described in a new publication authored by NDSU's Carl Dahlen and Charlie Stoltenow. The NDSU Extension Service publication "Dealing with Heat Stress in Beef Cattle Operations" is available at http://www.ag.ndsu.edu/pubs/ansci/beef/as1615.pdf or through your local Extension office.
Producers need to be very proactive about the potential seriousness of pending weather scenarios. Common cow sense tells us that cattle should not be worked when the heat index indicates stress. Why? Those animals that have adapted to higher temperatures have a much larger tolerance for large swings in body temperature.
For instance, a camel obviously can tolerate heat, but a cow is not so fortunate. A cow prefers a very stable body temperature that preferably does not vary much more than 1 F under normal conditions.
Any activity can increase a cow's body temperature several degrees. Even inactivity during a period of a high heat can increase a cow's body temperature.