Re-assessing quantity and quality of farm water

As the dry seasonal conditions continue, Agriculture Victoria is advising producers to re-assess and double-check their farm-water budgets and plans.

Agriculture Victoria Animal Industries Development Officer Richard Smith said availability and quality of water are key factors for productivity, health and welfare of livestock.

“Livestock water requirements vary and can be influenced by type/class of stock, activity level, climate and environmental conditions, feed, and water,” Mr Smith said.

During dry seasonal conditions, stock water requirements will increase if you are feeding fibrous and less digestible feed or by-products. The table below is an indication of the water needs of different classes of livestock and is a guide only.

Livestock Unit

Summer L/day

Winter L/day

Average L/day

Dairy cow, dry




Dairy cow, milking




Cattle weaners (250-300kg)




Ewes on dry feed




Prime lambs on dry pasture




Mature sheep on dry pasture




(DEDJTR (2016) Managing water supplies)

Mr Smith also recommends producers monitor the proportion of dissolved salts in any water source, as it is the main factor influencing water quality.

“The maximum salt concentration for healthy production for dairy cattle is 2500 ppm, higher levels will cause decline in production and impact animal health,” Mr Smith said.

“During summer and early autumn, the rate of water evaporation can result in a significant increase in dam salt concentration. If you are also feeding salt-based licks or by-products, you will need to factor in their salt components.

“High salt content will increase water intake, and can cause abdominal pain, loss of appetite, diarrhea and increased urination.

“Excessive salt concentration can cause death within six to 24 hours.”

Producers also need to be aware of the risk of high sediment loads and pollution, as manure, dust, and vegetation are blown or deposited into the water body. This can reduce the appeal to stock due to unpleasant smell, therefore reducing uptake.

Manure build-up, vegetation decay, and dead animals in water sources can increase the risk of diseases occurring including, E. coli and botulism.

“One study confirmed yearling cattle drinking clean water gained between 20 and 23 per cent more weight than those drinking contaminated water,” Mr Smith said.

“The same study found calves whose mothers were drinking clean water, were nine per cent heavier than calves feeding from cows drinking unclean water.”

The combination of low dam levels, high nutrient load, and high temperatures also increases the risk of algae blooms in late summer and early autumn.

These factors can cause excessive growth of algae which can block pipes and make the water unpalatable to stock. Producers need to be mindful of the animal health risk posed by blue-green algae.

“Depending on the toxicity of the bloom and the concentration of the toxin, between a few mouthfuls and several litres of water may be ingested before livestock show signs of poisoning,” Mr Smith said.

“It is also essential to understand your water quality and quantity if feeding higher than normal levels of grain or by-products.

“Livestock poorly adjusted to grain with poor quality or quantity water, are at an increased risk of grain poisoning.”

Re-assessing the quantity and quality of water on your properties, will allow producers to get the most out of the months ahead.

Producers may be eligible for On-Farm Emergency Water Infrastructure Rebate Scheme which offers a one-off 25 per cent rebate up to $25,000 (GST exclusive) to eligible primary producers for the costs associated with the purchase and installation of on-farm water infrastructure.

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