One of the key elements of a successful grazing system is having clean and abundant water available at all times. Just how much is needed? A lactating dairy cow consumes up to 25 gallons of water per day, while a beef cow requires up to 20 gallons. The total amount of water that must be provided is not just dependent on how many animals there are, but also how far animals must travel to the water tub, as well as the distance from the water tub to the water source.
In an intensively managed pasture with water 600- 900 feet away, animals will drink from the water tub individually as they feel like it. The flow rate should be such that the total water demand can be supplied within 4-8 hours. Water tubs should be sized so that 2-4% of the herd can drink at once. This is in contrast to larger, continuously grazed pastures where water is located at greater distances. In these situations, animals tend to go to water as a herd and therefore, the capacity and recharge ability must be greater to accommodate more animals at once.
Here’s an example of how to calculate water needs:
Animals and grazing system: 75 dairy cows in a rotational system
Daily consumption: 75 x 25 gallons = 1,875 gallons
Distance to water in a paddock: less than 900 feet
Tank refill time: 4 hours (240 minutes)
Required flow rate: 1,875 gallons/240 minutes = 7.8 gallons/minute
The flow rate and the distance to the water source (well, pond, etc.) are used to determine the size of the black plastic pipe that will meet the water demand. There are charts and tables available that can help you determine if, for example, 1 inch pipe is sufficient or if a larger diameter pipe is needed. In our climate, water lines in pastures are typically laid on top of the ground, since they are not used in winter, so protection from freezing is not necessary. Lines above the ground are cheaper to install, easier to repair, and are portable. Lines can be buried where they cross vehicle or animal lanes.
When calculating water needs, it is best not to design the system on the absolute minimum requirements. Building in a buffer will account for circumstances such as hot weather, which can double an animal’s water requirements. There are several other factors to consider when designing a water system including topography, type of pump used, pipe layout, and of course, cost. There is a great publication called ‘The ABCs of Livestock Watering Systems’ published by Michigan State University Extension. It can be found at HERE
UVM Extension is offering a 90% cost share program to install infrastructure to encourage livestock exclusion from streams in the Lake Champlain Watershed. If you are considering a water source development project including pipeline, water tanks, and fencing there may be funds available to help. For more information, contact our office at 388-4969.