Think you can handle the heat? Here’s the latest farm water shortages advice

With the mercury rising and dry weather set to continue and water shortages a possibility, here’s the latest official advice for handling livestock during droughts and hot weather.

In the Republic of Ireland, farmers – as well as the general public – have been asked to conserve water where possible.

Defra advises having a plan for what to do if water supplies are interrupted.

If supplies fail, it suggests alternative water sources could include making arrangements with neighbours who have boreholes.

If you have serious difficulties, the department recommends contacting your local council (and, in an emergency, the RSPCA) for advice.

Dry weather and dehydration

The greatest risk to animals from lack of water is dehydration. Young animals, housed animals on dry feed only, and lactating animals are at greatest risk.

To reduce the risk, you can give your animals water from the following sources (best to worst):

  • Drinking water;
  • Collected rainwater;
  • Reservoirs.

Talk to your vet about the risk of using alternative water sources and to find out if they need treatment.

Know what your requirements are

If you need to ration water you should meet the following daily minimum needs. Make sure you know how much your herd or flock requires.

Most cattle require 38L a day, but this figure can rise as high as 52L for milk cows. Horses need anywhere between 20L and 45L a day.

Smaller animals such as pigs and sheep drink much lower amounts. Chickens and hens need just half a litre a day and sheep need around 6L a day, while pigs can drink anywhere between 4L and 11.5L

You may need to allow more water for very young or old animals, or if the temperature or humidity rises.

For example, on a really hot day, 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.

You can reduce the amount of water your animals need by:

  • Giving them less feed;
  • Drying off any animals that are in late-stage lactation;
  • Ending egg production.

If water is rationed you should avoid salt poisoning in pigs.

If you can’t get enough water to your animals then you should consider transporting the animals to areas where enough water is available.

As a last resort, you should consider killing your animals humanely rather than letting them suffer.

The importance of flow rate

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.