Animal welfare at the fair: Thermoregulation and thermoneutral zone

Understanding how livestock thermoregulation and thermoneutral are important in providing excellent animal care.

Outdoor thermometer hanging by a pole.

Maintaining good animal welfare and animal care is paramount in the 4-H animal science experience. Youth, volunteers and parents spend months preparing animals to show at fair or exposition, a unique experience for both 4-H members and the animals. In order to maintain excellent animal welfare during a fair or expo, there are a few special considerations to keep in mind. This series from Michigan State University Extension will talk through several of these considerations starting with how animals thermoregulate, what is the thermoneutral zone and why it is important.

Thermoregulation is how the body regulates temperature in an acceptable range to avoid heat or cold stress. According to “Homeostatic Processes for Thermoregulation” by Jonathan A. Akin, there are two broad categories of animals and how they thermoregulate: (1) homeotherms, commonly referred to as “warm-blooded,” are animals that can maintain their own body temperature in relation to the external environment, like mammals and birds; and (2) poikilotherms or “cold-blooded” animals, cannot generate their own body heat and thus conform to the ambient temperature of their environment; most fish, amphibians, and reptiles are poikilotherms.

The animals most commonly raised as 4-H projects are all homeotherms and have many adaptations for thermoregulation. Some of those adaptations are hair, fur or body condition (how fat or thin an animal is), shivering, panting, how much food and water is consumed, activity level and many more.

According to the American Meteorological Society, the thermoneutral zone is defined as “the range of ambient temperature in which normal metabolism provides enough heat to maintain an essentially constant body temperature in homeothermic animals”. That means the animal doesn’t have to do any “work” to maintain their body temperature. The thermoneutral zone for many of our livestock, pets and pocket pets is a surprisingly narrow range, as shown in the table below.

Animal

Thermoneutral zone in degrees Fahrenheit

Cattle (beef)

32-77 (Beef Cattle Extension)

Cattle (dairy)

41-77 (University of Wisconsin – Madison)

Dog

68-86 (Purdue University Extension)

Goat

50-68 (Washington State University Extension)

Horse

40-80 (University of Tennessee Extension)

Poultry

60-75 (University of Minnesota Extension)

Rabbits

60-65 (Michigan State University Extension)

Sheep

70-88 (Washington State University Extension)

Swine

50-70 (Purdue University Extension)

It is important to note the temperatures listed above are the average thermoneutral zones for each species. There are many factors that can impact that range such as age, acclimation to ambient temperature, production status, bedding, body condition, coat length and coat color, to name a few. Also keep in mind that animals can survive and be well in temperatures outside of these ranges. The thermoneutral zone is the temperature range where an animal does not need to do any work to cool down or warm up to maintain a consistent internal environment.

Looking at the upper range of the thermoneutral zone temperatures, it becomes apparent that Michigan summers are often warmer than what is most comfortable for our animals. This leads into the second article in the series: heat stress, how to prevent it, how to identify it and how to treat it.

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