How much water will your cows drink during warm weather?

Temperatures are set to reach +20° over the coming days and it’s an opportune time to check if your cows are getting enough water.

It’s worth remembering that the primary component of milk is water and, therefore, ensuring your cows are provided with an adequate water supply is paramount to maximising yields during warm weather.

On a really hot day, Teagasc says, cows can drink anywhere from 60L/day up to 110L/day and they can typically drink at a rate of 14L/minute from a trough.

With this in mind, farmers are encouraged to carefully consider trough location, as cows don’t like to walk more than 250m to get a drink.

The research and advisory body also urges farmers to locate water troughs away from paddock gateways and farm roadways. This, says Teagasc, will shorten the walk to water, curtail bottlenecks and reduce wear and tear at gateways.

The importance of flow rate

Teagasc says that flow rate should be considered before trough size to ensure an adequate supply. However, large troughs provide more drinking space and can compensate a bit for poor flow rate at peak drinking time.

The main advantage of big troughs is that they give more space for drinking. Each cow drinking at a trough needs 450mm of space, which is measured along the trough rim.

For large herds, it may be necessary to install a second trough in the paddock. The troughs should be spaced suitably so that cows have no more than 250m to walk to water.

How to calculate flow rate

Assuming a daily demand of 80L/cow – almost 50% of which is consumed in a three-hour period soon after evening milking – an hourly flow rate of 13L/cow is required.

Therefore, for a 100-cow herd, the flow rate needs to be about 1,300L/hour or 22L/minute.

Steps to check the flow rate on your farm:
  • Mark the level of water in a trough;
  • Tie up the ballcock and empty, say, 25L from the trough;
  • Release the ballcock, hold it down and measure the time it takes (in minutes) to refill to the original mark;
  • Divide the 25L by the time taken to refill, e.g. if it takes a minute to refill then the flow rate is 25L/minute;
  • If the flow rate measure is less than that required for your herd, then your water supply system needs to be improved;
  • Check the flow rate of troughs around the farm.