Hot dry weather affecting stock water quality
Livestock owners have been urged to ensure stock have access to adequate clean water following reports of high levels of algae in some Riverina stock water supplies.
NSW Department of Primary Industries (DPI) Wagga Wagga beef cattle officer, Kate Parry, said January and February this year have been hotter and drier on average, resulting in lower dam water levels and increased potential for poor stock water quality.
"Recent water tests that have been conducted indicate high to very high levels of algae are present in some water reserves in the Riverina," she said.
"High levels of algae represent a significant risk to animal health.
"Increased algae levels may be due to nutrients being stirred up and increased contamination of remaining water with excrement in locations where stock have direct access to dams.
"Plant nutrients and excrement in water contribute to excess algae and plant growth, and introduces disease causing organisms such as bacteria, viruses and parasites.
"Adequate supplies of clean water are a key factor in maintaining stock health and production.
"In hot weather beef cattle drink between 50 and 140 litres a day, and dairy cattle may consume as much as 200 litres.
"Animals that drink more are likely to graze more, improving their weight gain."
"West Wyalong DPI’s Bob Thompson said treating algal blooms in dams early helped avoid animal health problems.
"The traditional copper sulphate or bluestone treatment used is the past is no longer registered, but just recently the use of simazine herbicide in farm dams to treat algal blooms has been approved in NSW under permit," he said.
"Users are required to read the permit before use and abide by the permit application requirements.
"There is no mandatory withholding period, but users are advised to wait at least three weeks for toxins released by the dying algae to dissipate, which is the same period as with the old bluestone treatment.
"Another option is using ferric alum blocks to reduce the availability of phosphorus to algae."
Ms Parry said reticulating water into well maintained troughs was a better option than allowing cattle to wade into muddy dams.
"It is vitally important that troughs are regularly checked to ensure the delivery of adequate good quality water," Ms Parry said.
More detailed information on managing stock water is available from local DPI livestock officers.
Permit number PER10994 for the use of Simazine to control blue green algae in dams, tanks and troughs in NSW is available at http://permits.apvma.gov.au/PER10994.PDF
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Media contact: Tom Braz 02 6391 3579, 0428 256 596