Planning for Livestock Water Needs

There are a myriad of resources available to livestock owners discussing grazing options. Rotational grazing, intensive grazing, paddock sizing, and forage varieties are all covered extensively. The one critical topic that is often overlooked is the livestock water supply.

Different species of livestock obviously require different amounts of water. A 1,200-pound cow will undoubtedly need more water than an 80-pound goat. The time of year also plays a significant role – livestock will consume much more water in the summer months than in the winter months. So how does a livestock producer determine how much water their herd may need?

There is some data available if a comprehensive search is completed. Dr. Ben Bartlett with the University of Michigan produced the publication “Watering Systems for Grazing Livestock” some years ago on the topic (now out of print). Dr. Jim Gerrish, with the University of Missouri, published research that indicated cow-calf pairs on Kentucky 31 Tall Fescue used up to 35 gallons of water per day per pair in the heat of the summer. Other sources, such as the Missouri Grazing Manual, NRC’s Nutrient Requirements of Beef Cattle, and an issue of Large Animal Veterinarian (May/June 1988), provide data based on maximum daily temperatures for dairy and beef cattle. Our local NRCS offices also have livestock water need calculations available.

Livestock will certainly water from a pond or stream if one is available. However, it is a much better practice to fence livestock away from streams and ponds to protect the water quality of those water sources. Erosion loads from hoof action entering and leaving the water source are significant concerns, and coliform and nutrient loading can also become an issue with larger concentrations of animals. Placing water troughs throughout a grazing area can also greatly enhance grazing efficiency since cattle seem to graze more within 700 – 800 feet of a water source.

The best option is to plan for the greatest livestock water need, usually in the July/August time frame in South Carolina. During that time, the daily temperatures are warmer, and forages may have a lower moisture content due to limited rainfall and heat stress, so livestock will typically drink more water per day during that time frame.

We recommend that you spend time with your local Extension Agent and NRCS Agent to best determine water needs and water trough placement for your livestock. The livestock water need estimates below may help you determine if your proposed water source will provide enough water for your livestock:

The greatest need for a cow-calf operation will be in the July/August time frame if the calves are close to weaning age. Adding the needs of a lactating beef cow and her 600-pound calf would indicate the pair needs approximately 32.5 gallons of water per day during that time. Planning for a 35 gallon per pair per day water supply would be in line with estimated needs in this case.

The next step would be to determine a total water need and a minimum necessary flow rate. For example, if the grower has 40 cow/calf pairs in that area, the maximum daily water use would be approximately (35 gal/day/pair x 40 pair =) 1,400 gallons of water per day. That amount of water *could* be supplied with a flow rate as small as (1,400 gallons/24 hours/60 minutes =) 0.98 gallons per minute *if* the pump were to operate 24 hours per day, 7 days per week. A much more realistic operation would use a larger flow rate – say 5 gpm – and size the water troughs, piping, and float valves so that cattle do not withdraw water more quickly than the pump can replenish it.

A larger available flow rate from the well will require larger piping to the pasture and allow installation of a smaller water trough. The design of a livestock watering system should consider flow rate, water trough size, and the number of animals drinking at any one time. Intensively grazed cattle seem to water in pairs and smaller groups, while cattle on a more traditional two-week rotation generally water as an entire herd. Suppose the entire herd comes to the water trough at one time. In that case, care must be given to provide a large enough trough and/or limit the number of animals drinking from the trough at any one time to ensure the trough always have water available. According to Dr. Bartlett, cattle seem to drink water at a rate of 1 to 4 gallons per minute. Estimating that a cow may only consume about 40% of her daily water need at any one time, a grower may use the number of animals at the trough at any one time, the flow rate from the well (and that is allowed through the float valve), and the amount of water that should be left in the water trough when herd watering is completed to determine a minimum water trough size.

Plan to place water troughs in the open, away from trees. Livestock prefer drinking water that is closer to their body temperature. Placing a water trough under a tree may result in the need to remove leaves and detritus regularly. After installing a watering system, always make sure water troughs are in place and filled before moving livestock to a new grazing area. This will ensure that the livestock always has access to water and prevent possible damage to the water trough if thirsty animals try to drink while it is filling.

The USDA Farm Services Agency sometimes has cost-share assistance programs for the installation of livestock watering systems in conjunction with fencing livestock away from streams and ponds. Check with your local FSA office for more information on these programs.

Photo: A typical freeze-proof water trough installation shared between two pastures.  Image Credit, Bryan Smith.

Submitted by Bryan Smith, Area Extension Agent – Agricultural Engineer

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