Managing water in the dry – southern Australia

This second in our series on planning for tough seasons focuses on monitoring water and calculating requirements for livestock in hot, dry weather.

Associate Professor Bruce Allworth, Director of the Fred Morley Centre with Charles Sturt University’s School of Animal and Veterinary Sciences, said water quality and quantity is vital for livestock health and performance.

“Insufficient water has very serious consequences and can result in salt poisoning, dehydration and death,” he said.

“It is very important to have adequate waters available across the property as it is difficult to rewater stock if they have not been able to have a drink for more than 48-72 hours in very hot conditions.”

Bruce said the two critical factors of dry season water management are calculating livestock requirements and monitoring watering points.

Calculating

While the rough rule of thumb is that grazing animals will drink on average 10% of their body weight/day, this is highly variable and depends on the species and class of stock, feed available, and temperature. For example, lactating animals need more water than dry animals.

Diet plays a big part in water requirements. Good green pasture can supply virtually all an animal’s water needs, but during drought, when feed is more fibrous and less digestible, stock require more water.

“It’s easy to underestimate the amount of water sheep and cattle need in the dry season because they are not getting moisture out of pastures,” Bruce said.

In a dry spring like this, there are less pastures and dry matter content can increase significantly to as much as 80%, increasing livestock’s reliance on watering points.

In normal conditions with good quality water, consumption in summer will be about 40% higher than in winter, but in extreme conditions water consumption can increase by 78% (NSW DPI Primefact 326).

Factors such as shearing – which removes the fleece as insulation – and insufficient shade can increase the heat load of sheep during hot weather, increasing water demand.

Monitoring

When it comes to monitoring waters, Bruce's advice is:

• Keep an eye on dams as they dry out, especially in mixed farming enterprises as cattle can pug up the edges and increase the risk of sheep getting stuck.
• Consider fencing off dams and providing alternative water sources as part of your dry season water management plan.
• Monitor dams for blue-green algae as lower water levels, silt and animal waste can promote algae blooms.
• Monitor the flow rate into troughs as livestock – especially cattle – can become impatient and damage water infrastructure if it fills up too slowly.
• Investing in remote water monitoring technology can provide regular, real-time readings and reduce stress, labour and water runs.
• Evaporation can increase salinity in some water.

Bruce said confining stock on-farm in a  ‘droughtlot’, is another strategy to minimise the energy used walking to feed and water, however there are guidelines around minimum trough space.

Resources

• NSW DPI Primefacts: Water requirements for sheep and cattle: Information on factors which impact the suitability of water for stock use including water quality, feed quality, temperature and livestock breed, age and condition.
• Remote water monitoring: View a video from an MLA-funded Producer Demonstration Site at Gilgai Farms, Geurie, NSW, which used telemetry to check water levels remotely from a smart phone.
• Managing sheep in droughtlots: a best practice guide: Practical guidelines and examples for feeding and managing sheep during dry seasons and drought years.
• Making More From Sheep: A guide to collection information for a water stocktake.

Contact: Associate Professor Bruce Allworth E: ballworth@csu.edu.au