Water quality demonstration – what happened

Ken Solly, Ken Solly Business Services and Bindi Hunter, Agriculture Victoria

In the autumn 2026 edition of SheepNotes, we reported on a water demonstration trial set up in south west Victoria. The demonstration was established because the farmer believed lamb growth rates were lower than expected and was concerned about high levels of E. coli and other bacteria in a dam. At the time (November 2025) the dam was tested with the following colony forming units results (CFU) which are well above recommendations:

• E. coli – 2,000 CFU/100ml
• Coliforms – 2,000 CFU/100ml

Other bacteria – 290,000 CFU/100ml

The site was “Barooka” at Scotts Creek (Timboon–Simpson), managed by Cory Collins and Nicole Burvill. The property is owned by the Goode family whose main farm is at Kingston, South Australia. Each year they transfer approximately 7,000 lambs from Kingston to Barooka to finish them to 22 kg carcass weight.

Table 1: Water quality measurement of the treatments (ranges represent the fluctuation over the 2 months of the trial)

Recommended ranges for pH of water for sheep is 5 to 9; for EC is <6000 (µS/cm) (refer to reference item 2) and for TDS – <3,600 mg/l (refer to reference item 2); E. coli – <100 CFU/100 ml (refer to reference item 1).

Water quality recommendations

Guidance on acceptable levels of E. coli and other bacteria in livestock drinking water varies between sources. As a guide the Agriculture Victoria website states that total coliforms should be <2,000 CFU/100 mL for livestock drinking water. Other resources are listed in the references.

The demonstration

The trial began 1 March, 2026. At that time, the water quality in the dam had improved: E. coli 60, Coliforms 220, other bacteria 250,000 CFU/100ml but levels bounced around throughout the demonstration.

The trial involved 100 lambs (Merino x Hampshire Down) in 50 m x 50 m pens each supplied with differing water quality. Lambs were weighed on entry and randomly drafted into the different treatment pens (20 lambs per pen). Lambs were in containment for 69 days. Each treatment had a tank and trough supplying the different quality water:

• A – rainwater from the shed roof
• B – dam with better water quality
• C – initial dam sampled in 2025
• D – initial dam water treated with sodium hypochlorite
• E – initial dam water with a magnetic ‘AquaSplit’, (a water purifier)

Table 1 shows the water quality metrics for the 5 treatments. The water quality on average did not exceed recommended guidelines, but the range caused by variation over time, occasionally did.

Lambs were fed barley/lupins with a buffer and ad lib straw. Lambs were weighed individually at the start of the trial, after one month and two months. An Optiweigh was also used in 2 pens (pens A and C) to monitor progress. Water flow rate meters were used to measure the water intake of lambs in each pen. Water was sampled weekly in the tanks and troughs and tested at Southern Scientific in Hamilton.

Results

Water intake

The temperature was quite mild over the trial. Water intake ranged from 4 l/hd/day to 0.5 l/hd/day and was aligned to air temperature. Table 6 shows the average intake at 2.2 to 2.7 l/hd/day across the different water treatments in the trial.

Water quality results in each tank fluctuated. Bacterial loads were generally higher when the tank levels dropped. Even the fresh water from the shed roof spiked in bacteria load after a big rainfall event flushed the system.

We found greater differences in water quality between tanks and troughs than between the various water sources. This was probably caused by some regurgitated grain and low trough volumes (which made cleaning easier). Troughs were initially cleaned thoroughly every second day, but cleaning was increased to daily. (The Victorian code of practice for troughs in intensive systems is “Troughs should be equipped with drain plugs to assist cleaning. Where grain is fed, troughs should be cleaned at least daily. “[See item 5 in Reference section at end of article]).

Bacteria load in the treated water (sodium hypochlorite) crept up over time and needed retreating within the same tank load.

Lamb performance

Table 2: Daily average consumption of grain, straw and water for each treatment

As shown in Table 2, there was no, or very little, difference between treatments in hay or grain intakes.

Table 3 shows the start and end weights of the lambs. Average, minimum and maximum growth rates over the 69 days and are included to show the variation.

Overall, there were small or no differences in lamb growth rates between the treatments. This may have been because the water quality was generally not poor enough to impact growth rates, and/or that lambs had acclimatised to the water quality. Using a terminal sire breed that has a focus on meat eating quality rather than optimal growth rates, may explain lower growth rates than expected.

After rain in March, many lambs developed foot scald due to the mud. The lambs were foot bathed and improved quickly. However, lambs lost 2 kilograms during this period, which reduced weight gain by 30 grams per day over the length of the trial. The weight loss and recovery were picked up in the pens with the Optiweighs.

There were some lambs in each treatment that hardly put on any weight over the trial period. This could be for a range of reasons such as genetics, acidosis or other health reasons. These lambs would usually be removed from a feedlot but remained for this trial.

Table 3: Start and end weights of lambs in each treatment with average daily growth rates, minimum and maximum

Summary outcomes and lessons learned

• None of the water quality treatments impacted lamb performance.
• Clean troughs regularly.
• Daily water intake varied significantly, aligned to temperature.
• Lamb growth rates were lower than expected, likely due to terminal sire selection and animal health issues.
• Growth rates varied considerably between individual lambs – some lambs hardly grew. In future these lambs should be removed but were kept in the group for the purpose of the trial.
• Rain created muddy pen conditions that reduced growth rates due to foot scald. Optiweigh was useful to pick up this weight loss early.
• Hay racks could reduce wastage.
• Concrete pads around troughs could improve drainage.

References

1. Livestock drinking water guidelines (Water Quality Australia)
2. Water supply in stock containment areas (Agriculture Victoria)
3. Water for livestock: interpreting water quality tests (NSW DPIRD)
4. Managing contaminated livestock water (Agriculture Victoria)
5. Code of Accepted Farming Practice for the Welfare of Sheep (Victoria) (Agriculture Victoria)

Acknowledgements and funding

• Barooka Proprietors – (the Goode Family)
• Ken Solly Business Services
• Cory Collins and Nicole Burvill

This demonstration was delivered with Agriculture Victoria as part of the Victorian Government’s statewide Drought Support Package.