The following is the second of a two-part series about design specifications for feed and water spaces in freestall barns. Water plays an important role in milk production, temperature control and body functions for dairy cattle. Cows may consume 4.5 to 5 pounds of water from drinking and feed per pound of milk produced. Providing the opportunity for cows to consume a relatively large quantity of clean, fresh water is essential.
Body functions of water include:
•transport of nutrients and other compounds to and from body cells
•aid in digestion and metabolism of nutrients
•elimination of waste materials (urine, feces and respiration) and excess heat (perspiration) from the body
•maintaining a proper fluid and ion balance in the body
•providing the developing fetus with a fluid environment
Water also makes up approximately 87 percent of the milk secreted by the cow.
Drinking water satisfies 80 to 90 percent of the dairy cow’s total water needs. Therefore, it is logical that plenty of good-quality drinking water be conveniently located in areas where cows spend most of their time and offered from watering units that allow the cows to drink water easily. The water system must be designed to deliver water to each station at the proper rate and keep up with peak demand. Each water station should also be easy to clean and cleaned regularly.
Each day, dairy cows drink large quantities of water. How much they drink depends on:
•average dry matter (DM) content of the feed
•stage of lactation
Temperature and humidity has a dramatic affect on water consumption. Hot, dry conditions increase water losses through evaporation and urination but reduce water through feces. Typically, cattle under heat stress require 1.2 to 2 times more water per day than cattle in the thermal neutral temperature zone.
Considerations for waterer design in freestall shelters
Cows may spend six hours per day eating (12 meals at 30 minutes each) but only five to 10 minutes per day drinking water. However, this does not reduce the need for well-designed, conveniently located watering stations. Cows seem to have the highest water intake during hours when feed intake is the greatest. When given the opportunity, cows tend to alternately consume feed and drink water. Fresh, clean water should be available whenever cows consume feed. Cows also seem to readily drink water soon after being milked.
At least two watering locations should be provided for groups larger than 10 cows. Multiple water stations help to reduce the affect of dominant cows since alternative locations are available.
Even though cows spend a relatively short time each day consuming water, they tend to gather near water stations, especially during hot weather. Therefore, the waterer should be sized to accommodate multiple users at one time. “Rule of thumb” recommendations vary by climate. Midwest Plan Service guidelines suggest a minimum of one waterer location or 2 feet of accessible trough perimeter for every 15 to 20 cows. This allows space for approximately 5 to 7 percent of a group to drink at the same time. A 100-cow group would require 10 to 14 feet of accessible trough perimeter.
For groups of 200 cows or less, Armstrong suggests the water stations should accommodate 15 percent of the group at the same time, allowing 2 feet of accessible perimeter per cow. For example, a group of 100 cows requires 30 feet of accessible trough perimeter.
For groups larger than 200 cows, Armstrong suggests the waterers should accommodate 20 percent of the group at once. This recommendation is based on milking parlor size and performance. More than enough watering space is provided to accommodate cows released from one side of the milking parlor. With 12 to 15 minutes between group changes, the thirst of the previous group may be satisfied by the time the next group arrives.
Armstrong’s recommendation is for more arid climates where water loss by evaporation from the skin is higher and the period the cows experience heat stress is longer. However, many areas of the United States experience extended periods of hot weather where cows experience heat stress. Therefore, having plenty of drinking water available, and even supplementing it during warm weather, is very desirable.
A crossover lane to the feeding area should be provided every 60 to 80 feet to allow better access and more uniform feed consumption along the length of the feeding area. As mentioned earlier, fresh, clean water should also be available whenever cows consume feed. Crossover lanes provide an excellent and logical location for waterers.
The surface around the water station should be firm and provide a confident footing for the cows. The area should slope away from the watering unit approximately 0.5 inch per foot to prevent puddles.
Waterers should be easily accessible to the cows. Barriers that do not allow free access to the waterer are discouraged. Locating the watering units at the feed barriers is not recommended. This reduces available feeding space, may easily contaminate waterers, cause sloppy feeding areas and make it harder to remove leftover feed.
Waterer height in freestall shelters
The height of the waterer is measured from the floor to the top edge the cow must reach over to get the water. The water surface should be approximately 2 to 4 inches below the top edge to avoid excessive spillage and splashing.
A height of 24 to 32 inches seems to be reasonable for mature Holstein cows. This places the water surface at 20 to 30 inches above the floor level, with 2 to 4 inches below the top edge. Reducing these heights 2 to 3 inches may be logical for Jerseys.
Water depth in freestall shelters
The water depth presented is also important. It should be deep enough to allow the cow to submerge her muzzle 1 to 2 inches into the water and consume as much as she desires without causing her to gulp air. Preferably the water dispenser should maintain a minimum water depth of 3 inches as the cow is drinking.
Relatively shallow water depths of 3 to 8 inches are preferred since they can offer fresher water and reduced accumulation of debris. However, if the flow rate cannot maintain the desired water depth, then waterer capacity should be increased. Keeping the waterer clean and free of debris is important with all waterers, but more careful attention may be needed when deeper water depths are offered.
Protecting the waterers in freestall shelters
Guards, barriers and steps are used to prevent cows from urinating, defecating and standing in waterers. These methods can be effective but should not hinder cows from using the water or prevent them from drawing water easily.
A step at the base of the waterer is often used to reduce the chance of cows contaminating the water with urine or manure. This is somewhat successful, but in most dairy systems, there is an opportunity for caretakers to observe the water stations several times per day for contamination and clean them if needed. A concrete support base that provides a 2-inch ledge around the perimeter of the waterer will help protect the bottom section from damage.
Some cows will stand with their front feet in a water trough. A guardrail can be place directly above the edge of the water trough to discourage this behavior. The guardrail should be securely fastened and not restrict access or cause injury to cows. For the trough height discussed earlier, the recommended horizontal rail position is 48 to 60 inches from the floor and in line with the edge of the waterer. Provide at least 24 inches of clear opening between the top edge of the waterer and the rail.
Waterers used in freestall shelters
In freestall shelters, the cows share the waterers provided in the group. There are several styles of watering units available and used in freestall shelters. Watering units that present a generous surface and volume of water that one or more cows can easily drink from at the same time are preferred. A non-backsiphoning valve must deliver water. The valves should be protected to prevent damage or malfunction by the cattle. An outlet should be provided to allow easy and complete removal of water and sediment when cleaning. The drain plug should be easy for the caretaker to use but protected to prevent accidental removal by cows.
Freezing of the exposed valves and water lines are a concern in some climates. Some producers open a small diameter (1/8-inch to 1/4-inch) overflow tube during cold weather to allow the inlet valve to continuously deliver a small flow of water and reduce chances of freezing. Consideration should be given to proper drainage of overflow water to prevent ice build-up and slippery conditions around the water station.
Water troughs are commonly made of metal, concrete or plastic. The water depth is commonly 3 to 8 inches so the water offered stays relatively fresh and clean. When water flow to the unit is adequate, troughs are preferred in dairy shelters since more than one cow can drink at the same time. Water cleanliness is relatively easy to observe, and most can be emptied and cleaned easily.
Vats, or tanks, often provide large quantities of water since water depth and the height of the tank are very similar. This type of waterer is often selected when the recover rate of the water system is slow or the water supply is sporadic. They are often made of concrete, and due to the water depth, observation of sediment build-up and condition of the water can be less obvious. The outlet should allow both water and sediments to drain completely for cleaning
A popular watering device in freestall shelters is the tip tank. These units are typically fabricated from metal and hold 75 or more gallons of water. A non-backsiphoning float valve maintains the water level. The tank is mounted on an off-center pivot that keeps the tank relatively stable in the upright watering position. The tank may be overturned for cleaning, which may result in more frequent cleaning. However, regular scrubbing of the tank is still necessary.
Energy-free watering units use an insulated enclosure and the relatively stable temperature of the earth below the frost line to prevent freezing. A float, such as a ball or disc, seals the access opening when not in use. A non-backsiphoning float valve within the unit maintains the water level. Cows must push the floating device aside to drink. These units greatly reduce the chance of freezing; however, their design may also discourage cows from consuming as much water as they could.
The covers are effective in preventing freezing during cold weather but should be removed during warm weather to allow more convenient access. Observation of water quality and sediment build-up is not as obvious, so the caretaker must make an extra effort to monitor their condition and clean them regularly.
Heated waterers have been used in cold climates for decades. Typically, an electric or gas heating unit with an adjustable thermostat keeps the drinking water from freezing. Although the surface area of the water is much less than a trough, access to the water is usually better than energy-free units, which may improve intake. The water depth is usually adequate, and they are relatively easy to clean. Concerns with these units include the additional cost of providing electric service to each waterer, the cost of operation during cold weather and the danger of electrical malfunctions near water.
Keeping the water station clean
One thing all cattle watering units have in common is that they must be cleaned and cleaned often. Feed intake, milk production and animal health all depend heavily on drinking water intake so the producer must accept the responsibility of keeping the watering devices clean and in good repair. Accumulation of sediment such as feed, bedding and manure can contaminate the water and should be removed at least once per day. Weekly, or as needed, the watering device should be drained and scrubbed using a diluted chlorine solution.
Far too often the task of cleaning the watering units is not performed as regularly as needed. Some manufacturers even advertise “self-cleaning” waterers. These systems claim that combination of small reservoir and higher flow rate put the sediments in suspension allowing the cows to draw them in with the water. Relying totally on this cleaning feature is not a good management practice since other materials such as sand, sawdust, bird droppings and manure may make up a portion of the sediment present. Producers also find that the waterers still need to be scrubbed clean regularly to ensure good water quality and animal acceptance.
Water system design considerations
All of the details and factors concerning the design of a water supply system cannot be covered in this [article]. However, it is important to cover some details that affect the delivery of water to the watering locations. Reference handbooks and plumbers can provide detailed information on water system design.
The pump does not solely determine the volume of water delivered to a water station. Valves, fittings, pipe size, pipe material and elevation head all develop resistance that reduces flow rate to the watering device. The challenge in water system design is to size the lines large enough to provide adequate flow but small enough to prevent large pressure drops that may result in system failure.
Connections should be installed to prevent the backsiphoning of polluted water back into the water system. Disease-causing organisms may get into the system through backflow or backsiphoning from livestock waterers, toilets, sinks and flooded pump pits. Steps must be taken to prevent this from occurring. All cross connections and interconnections between potable and non-potable water systems should be eliminated.
Backsiphoning is caused by a lack of pressure in the system causing the fixture to drain back into the piping. The valves used in livestock watering units must be non-backsiphoning. When the waterer is full, there must be an air gap at least twice the diameter of the outlet between the water surface and the outlet.
In many cases, the well pump capacity is unable to keep up with peak demand of the watering system; therefore, a reservoir is needed to allow the system to respond to (and satisfy) demand. Reservoirs can also eliminate the relatively short and frequent pumping cycles that occur in a system without much reserve.
Water may be pumped to a reservoir over a longer period of time then removed as needed. The size of the reservoir depends on the demand of the system and capacity of the well pump. Some reservoirs are sized to hold the amount of water the well pump can supply in eight or more hours at a time. A second pump sends water through the main and branch water lines as needed.
Using the watering unit as a reservoir is not highly recommended due to the potential of contamination that may occur if the tank is not drained regularly for cleaning and sediment removal.
Buried tanks usually create less of an obstacle than above-ground storage tanks and may provide more uniform water temperature. Reservoirs made from concrete or polyethylene is preferred. They should be covered and designed to prevent contamination from surface runoff.
Water supply lines for freestall shelters
The information presented here only considers the drinking water supplied to the shelter for the cows. Additional water volume and flow rates required for other uses such as cleaning and supplemental cooling must also be considered in the total design of the system.
The type of watering unit and shelter style can influence the design of the supply line. In freestall and loose housing, cows must travel some distance and share the waterers with a number of other cows. If a cow can drink water at three to five gallons per minute (gpm), then the recovery rate should satisfy this demand. If a watering unit allows three cows to draw water at the same time, then the recovery rate should be nine to 15 gpm at that location. If three similar watering units are available to the group at different locations, then the total demand for that group is 27 to 45 gpm. At peak times, if space for 15 percent of a group of 100 cows is available, then the cows may consume 45 to 75 gpm.
Flexible plastic pipe is common for underground piping because of installation ease and economy. It is available in coils of 100 feet or more. Joints are easy to make, and corrosive soils do not create a problem. This pipe is very resistant to inside pipe corrosion. Plastic pipe with at least an 80 pounds per square inch (psi) rating is recommended.
Feed and water are essential elements in the production of quality milk. Dairy system designers need to pay close attention to the needs of cows when creating designs and recommendations for the feeding area and water stations. These areas should allow each cow in a group to consume large volumes of fresh, good-quality feed and water, easily, comfortably and without injury. The design of the feeding and watering areas should also allow the caretaker to perform the tasks of feed delivery, observation, maintenance and cleaning easily and safely. Access to feed and water should not limit the production and profit potential of a modern dairy enterprise.
References omitted but are available upon request at email@example.com
—Excerpts from “Dairy Housing and Equipment Systems: Managing and Planning for Profitability” Proceedings
Q. What concerns (or impresses) you most about waterer designs and placement you’ve seen in recent years?
It is encouraging to see producers are more concerned with providing convenient access to “trough-type” waterers than with the number of water lines they need to run. Trough-type waterers allow good access for multiple cows at the same time have become the preferred choice over other designs that have more limited access.
Keeping watering units clean is a major concern. Tip-type trough waterers are easy to clean, but producers soon find that dumping multiple waterers each day can add a significant amount to the waste stream. As long as the water supply can keep up with demand, selecting a waterer that holds only 25 to 30 gallons in reserve vs. 80 to 90 gallons can reduce waste and encourage regular cleaning.