Heather Hamilton, editor of the Wyoming Livestock Roundup
Article compiled from Journal of Animal Science articles from K-State and the University of Missouri
(Previously published on the Wyoming Livestock Roundup)
Although Ohio and 
Wyoming weather conditions may differ, this weekends cold spell put shepherds to the test as lambs continued to hit the ground. Ensuring that our small ruminants have an ample supply of fresh water is on every producers check list, but monitoring water temperature may not be. Water temperature may play a bigger role than you thought before. To learn more, be sure to read on below!
It’s cold during Wyoming winters and producers utilize many production practices to reduce weather impacts on livestock. Providing warm water to livestock during cold months is an option that can increase water intake and reduce energy needs.
A small calorie is defined as the energy needed to raise one gram of water one degree Celsius. There are 28.35 grams per ounce and 128 fluid ounces per gallon. Multiplying the two numbers together equals 3,629 grams per gallon.
If a mature, dry cow drinks six gallons of 32°F water each day and her average body temperature is 101.5°F, she is using a lot of calories to warm that water up to her body temperature.
If a producer can practically increase the temperature of the water his livestock are consuming, he can make his winter feed go farther. Instead of using energy for internal temperature control, animals could utilize it for other needs, such as putting on more weight. Another benefit is the increased water availability, as livestock won’t have to wait until ice has been chopped. Not chopping ice every day would please many producers as well.
D.L. Brod, K.K. Bolsten, and B.E. Brent of the University of Missouri conducted two trials demonstrating that cold water dropped the temperature of the rumen. In each of the trials four Holstein cows on an alfalfa-brome grass hay diet were subjected to 34°F, 57°F, 80°F, and 103°F water. Multiple temperature readings were gathered to determine results.
The most severe temperature drop occurred when the cows consumed 34°F water. Upon ingestion, the water immediately dropped the lower rumen temperature from 102.9°F – 79.8°F, a 23°F difference. Within 10 minutes the middle rumen temperature went from 103.9°F – 93.6 °F and the upper rumen went from 102.1°F – 99.8°F.
Upon reaching the lowest recorded temperature, the rumen rapidly warmed up several degrees, then slowed to a gradual climb back to the original temperature. About 270 minutes later the rumen reached its pre-watering temperature.
The article noted that cows consumed much less 34°F water than they did when presented with warmer water. There was no significant difference in consumption between the 57°F and 80°F water. The highest levels of ingestion occurred with the 103°F water.
Brod, Bolsten, and Brent conducted another study with Kansas State University to determine the effect of cold water on rumen temperature and digestion in sheep.
Four wethers on an alfalfa pellet diet were given four water treatments. Water temperatures were at 32°F, 50°F, 68°F and 86°F. After consuming the 32°F water it took 108 minutes for the wether’s rumens to return to their pre-drinking temperature. After consuming the 50°F and 68°F water it took 96 minutes and after drinking 86°F water it took 72 minutes to return each wether’s rumen to its initial temperature.
The study also suggested that drinking the 32°F water suppressed microbial activity in the rumen. Evidence included an elevation in pH four hours after feeding when the wethers drank 32°F water compared to lower pH values after warmer water was consumed. Concentrations of volatile fatty acids (VFA’s) and ammonia-nitrogen for the 32°F water were depressed, as were digestibility values when compared to levels found after consuming warmer water.
Both studies found benefits to providing livestock with warm water during cold months. The potentially increased consumption and digestibility of feed during winter months could be very beneficial to almost all livestock producers.
Producers growing lambs or calves could potentially see increased gains as a result of less energy being used to warm water internally. Ranchers wintering cows could maintain cattle using less energy, or choose to keep cows in better condition.
Some producers are fortunate to have hot water wells or creeks on their operation. For those who don’t have access to naturally occurring warm water there are a variety of water heating systems available. These may or may not be feasible to an operation. However, knowing the potential benefits of providing warm water to livestock can help producers make more informed decisions and aid in determining if providing warm water is economically viable.