Over the last number of days, the severe heat has more than likely tested your water system and troughs as the herd’s water intake will have doubled in those conditions.
Cows on a hot day could drink well in excess of 100L/day, especially when temperatures were above 25℃ and dry matter content of the grass increases.
This additional demand for water can result in pressure on water systems, where the trough size gets exposed or the flow rates prove to be sub-optimal.
The first thing that should be checked before cows go into a paddock is whether they have access to water or whether the tap on the trough is turned on, especially with the warm weather we are experiencing.
Peak water demands occur after evening milking, and to a lesser extent after morning milking – a trough space of 450mm/cow should be allowed.
Ensuring access to water
Quite often, water troughs are set up on roadways in order to provide for two or three paddocks, but this can restrict the herd’s access to water as it results in queuing.
In an ideal situation, the water trough should be located in the middle of the paddock so the cows can access water from all angles.
Milk is almost 90% water and cows drink 4-4.5L of water/kg of milk produced – daily drinking requirements vary but can be between 60-140L/cow.
On an average day, a 150-cow herd could drink up to 10,000L (65L/cow) – the water system must be sufficient to ensure that this quantity of water is delivered to the paddock.
A flow rate of 0.2L per cow/minute and a trough volume of about 5-7 L/cow is generally recommended. For example, a flow rate of 30L per minute and approximately 900L (240 gallons) troughs per 150 cows.
An appropriate size pipe will allow for a good flow rate. If a trough is empty after cows use it, it is likely that the flow of water is lower than demand and so troughs should be inspected before and after each milking.
A wider pipe is often required to increase the amount of water that can flow through the system. For the main waterline, a 38-42mm internal diameter is required for a 150-cow herd.
Farmers should also use “full flow” type ballcocks in all new troughs. These ballcocks typically have 9-12mm jets, providing a good flow rate even with low pressures at the ballcock.
A standard high pressure ballcock jet (3mm diameter) is very restrictive even where pressure at the ballcock is high.
When inspecting a water trough after a grazing or during a grazing, the following should be quite noticeable:
- No queuing at water trough;
- Trough always filled after milking;
- No leakage;
- No cow tracks to trough as it indicates a long walk to troughs.
When cows have to walk long distances to and from the parlour, it may be useful to install a trough along a highly trafficked area, as long as it does not disrupt cow flow.
These trough should be installed in wide areas of passageways, as you don’t want them causing delays and potential pinch points.
Where possible, these troughs could be placed in an area that can only be accessed after milking, or while cows are in the collecting yard.
Troughs should be regularly cleaned out – remove any algae or objects that are present in the water trough, as they can potentially reduce a cow’s water intake.
Troughs should be level and have no leaks. Repair any leaks as soon as possible to stop pressure from dropping and allow a trough space for at least 10% of the herd to drink at once.
