Livestock producers are being urged to pay attention to the water their thirsty animals drink during current dry spells – and enjoy the payoff in health and productivity. And this also forms part of good biosecurity practices, according Bonnie Skinner at Livestock Biosecurity Network in NSW.
Ms Skinner, the network’s biosecurity and extension manager, said some of the main water quality concerns of producers during extended hot dry periods should be salinity, algal growth, and contamination of water by manure and other pollutants.
“During prolonged hot weather evaporation can greatly increase the salinity of water in troughs and dams,” she said.
“Dams can evaporate anywhere from 1 to 2.5 metres during the course of a year. Livestock can tolerate saline water to certain concentrations when introduced slowly, however sudden marked increases may cause stock to refuse to drink it or cause toxic effects.”
Ms Skinner said water should be tested and monitored monthly for salinity during summer, and particularly during drought. Water troughs should be flushed and scrubbed as frequently as practical – once to twice weekly is ideal.
She says algae build-up in water reduces its palatability and can block water pipes and outlets,. Some types of algae are toxic to stock, the most notable of which is the blue-green variety.
“Water troughs should be cleaned regularly to prevent algal build-up,” Ms Skinner said. “Shading troughs where possible and ensuring tanks are fitted with covers will help to reduce the amount of sunlight.
“Chemical control is dependent on the type of water being treated and may include simazine, chelated copper or copper sulphate.”
She said chemical treatment of blue-green algae would cause toxins to be released and so stock must be kept off for the length of the withholding period or 14 days, whichever is longer.
Consideration should be made to reticulating from dams into troughs and fencing off dam areas if possible. Fencing off the windward side of the dam with closed wire fencing may help to trap blown dry vegetation from entering the dam.