It’s getting hot in here: Paying attention to temperatures on dairy


I find it quite fascinating at how certain sayings develop and then we sometimes forget how they originated, but we continue to use them.

I think one of these is “The temperature is on the rise.” Although ‘rise” can refer to “going higher,” this saying developed from our watching the mercury increase in the channel of the thermometer as the temperature increased. But how often nowadays do we use a mercury thermometer?

(Do you remember the days when one of them would break and then you would play with the beads of mercury as they rolled around on a solid surface? But not today. Mercury is regarded as a hazardous heavy metal that if spilled, the hazardous material team must be called in for the clean-up in their robed attire.)

Let’s talk temperatures

With the extremely wet spring and summer, followed by a recent major rise in temperature (heat wave), it is a good time to reflect on how much we use temperature readings in dairy farm management today. Granted, most of these readings are from digital instruments rather than an old-fashioned thermometer where we had to shake the mercury back to the bottom and then watch it rise to obtain our reading.

Some important use of temperature readings on the dairy farm include:

Animal health

1) Taking the temperature of any ill animal is important in identifying whether the illness is caused by an infection;

2) Daily temperature readings (at least for one week) as part of the fresh cow protocol is important in catching an infection quickly;

3) Daily temperature readings (at least for one week) of newborn calves also is important in reducing the severity of disease and developing a rapid treatment response.

These readings are often taken with digital thermometers, but some of the herd management systems today offer ear devices that record several different types of data, including the animal’s body temperature.

These instruments take a reading and then based on research, algorithms are used to convert the readings to core body temperature. These have been used in the medical field for some time.

Watch for deviation

On the dairy farm, the actual temperature readings are important, but the even more important aspect is the deviation in a cow’s normal temperature, especially if it is elevated but also if it drops low.


Temperature recording devices located in the animal’s housing area (proximity to animal’s actual environment) can be used to control fans, misters, and raising and lowering curtains.


Although is it known that the animal’s body temperature increases slightly at ovulation, the magnitude of change and the timing is such that we don’t typically use the animal’s body temperature for breeding decisions. However, the use of the thermometer is very important in proper thawing of the semen for artificial insemination. Malfunction of this thermometer for semen thawing can cause reduced fertility on dairy farms.

Milk Quality

The normal body temperature of the cow is about 101 degrees F. (thus the approximate temperature of the milk before extracted from the cow), but we want to cool the milk as rapidly as possible to about 40 degrees. The more quickly we do this, the less opportunity bacteria have to multiply. Thus, the use of a plate cooler aids in providing that heat exchange before the milk arrives in the bulk tank for cooling. We watch that bulk tank temperature reading to make sure the milk is properly cooled and the milk hauler records the temperature when the milk is picked up.

Feed Quality

Proper harvest, storage, and feed-out of wet forages (e.g., corn silage and haylage) is very important in reducing feed shrink (wastage). Silage harvested too dry will excessively heat and poor face management will introduce oxygen into the feed that will result in heating. This will reduce feed quality and palatability. Today, infrared imaging of the silage face to identify “hot spots” can be very revealing of feed quality and silage management. Even the simple hand-held digital, infrared instruments available for cooking meat, etc. can be useful in checking the temperature of the silage face.

So I may have forgotten one of the uses of measurement of temperature on the farm that comes to your mind, e.g. you are not sitting in an air-conditioned room that is thermostatically controlled as you read this, but you get the point.

Technology evolving

Temperature readings are very important to the management of today’s dairy farms. New instrumentation for measurement, recording, and use in controlling housing environments or making animal treatment decisions will continue to the developed. Use of this information can be valuable as long as it helps to improve cow health and comfort and in making valuable management decisions.

In some cases, we are collecting more information electronically on dairy farms than we know how to effectively use. So the saying of “information overload” may be with us for a while.

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