Pasture quality & stock water in focus at Field Day

On Friday, October 11, 2024, farmers gathered at the Moll family’s farm, ‘Elderslie,’ for the annual Evan Moll Gerogery Field Day. This long-standing field day, run in collaboration with Riverine Plains and the Moll family, has been an important community event for over 80 years.

The day was a fantastic opportunity for farmers to see the latest in wheat and canola varieties through the Grains Research and Development Corporation (GRDC) National Variety Trials (NVT), with the wheat session led by Peter Matthews and the canola session led by Kathi Hertel, both from NSW DPI. This was followed by sessions on frost assessment with Sheree Hamson, from Elders, as well as discussions on livestock feeding and stock water management, which were all highly relevant.

Practical guide to livestock feeding and water

Martin Preuss, Murray LLS discussed the importance of evaluating both the quantity and quality of available forage, to determine how many animals a pasture can support. The session highlighted how pasture assessments can help farmers better understand the amount of feed available (dry matter) and its nutritional value (quality). Key messages were to:

1. Assess dry matter availability

Dry matter (DM) refers to the amount (kg) of feed available per hectare (kg DM/ha) and can be measured by doing quadrant or ruler cuts, then weighing and drying samples. Alternatively, farmers can use tools such as pasture rulers (which convert heights to DM estimates using look-up tables, such as MLA’s pasture ruler, commercially available plate meters, electronic probes or visual estimates.

To convert DM to feed availability per hectare, first obtain the measure/estimate of pasture DM (i.e. 2,500 kg DM/ha) using one of the above methods, then calculate total available DM by multiplying DM kg/ha by the total hectares of your paddock (i.e a 10 ha paddock with 2,500 kg DM/ha, will have 25,000 kg DM total available feed).  

To avoid the risk of overgrazing, a correction factor can be applied to adjust the estimates based on the less productive areas of the paddock. A conservative approach would be to reduce the total estimated dry matter per hectare by 10-30%, depending on paddock conditions, such as rocky areas or lower productivity zones, to account for differences. The exact factor may vary depending on the specific conditions of the paddock.

Sheep require approximately 1.5-2.5% of their bodyweight in DM daily, therefore a 60 kg sheep will need 0.9 – 1.5 kg DM/day (60 kg x 0.015 – 0.025). Cattle typically need 2-3% of their body weight in DM daily, so a 500 kg cow will need 10 – 15 kg DM per day (500 kg x 0.02 – 0.03). To put this in context, a shopping bag filled with forage roughly equals the daily intake of a dry sheep (DSE), while a hessian grain bag represents about what a cow might consume in a day.

2. Assess pasture quality

In addition to quantity, pasture quality matters. Mixed pastures with a variety of grasses and legumes provide a higher-quality feed, especially during their active growing stages. The most useful estimate of pasture quality is digestibility, because it is directly related to the energy and protein content of the pasture, as well as the speed of digestion. Digestibility is mainly driven by the pasture’s stage of maturity and species composition (legumes usually have a higher digestibility than grasses), and can be measured via a feedtest. Additional methods to assess pasture quality are discussed in the PROGRAZE manual (Segment 2, page 4, see also below figure). 

By making regular dry matter assessments, farmers can optimise stocking rates based on available DM, maximising pasture utilisation, and boost productivity by making informed grazing decisions, increasing the efficiency of feed use and animal production.

Linking feed to water intake - assessing water availability and quality  

Martin Preuss & Paul Simpson, both Murray LLS, also ran a valuable session on assessing water availability and quality for livestock.

Animals need specific amounts of water based on their production and environment. For sheep, this is typically 2-6 litres/day, depending on weather and diet, while cattle need 35-60 litres/day, depending on their size and production stage.

Water directly affects the intake of feed; animals drinking more water will consume more feed, improving growth and production of meat, wool, or milk. A key part of determining stock water requirements is evaluating how much water is available. To do this, it’s important to estimate the volume of your available water resources (dams, tanks) and compare it with your animals’ daily water needs – read more about Stock-taking water supply for livestock (NSW DPI).

Water quality is also directly linked to water intake and it was recommended farmers:

• Test for contaminants by regularly checking water sources for salinity, pathogens, blue-green algae, and faecal matter; these are common issues that can negatively affect livestock health
• Monitor livestock performance by looking for signs of reduced weight gain or feed intake, which could indicate water quality problems — it may also be useful to compare livestock drinking from different water sources
• Ensure clean water availability by providing livestock with consistent access to fresh, clean water — this improves both water intake and overall feed consumption, leading to better growth and production

Read more about water quality and livestock (NSW DPI).

Biodiversity & water quality in farm dams

Clare Crane, ANU Sustainable Farms, also spoke about dams as vital infrastructure for farming, supporting livestock and irrigation needs. She also spoke about the different ways farmers can enhance biodiversity and water quality in farm dams by:

1. Limiting livestock access with fencing: this prevents livestock from entering the dam, reducing contamination from faeces and preventing soil erosion, while also preserving surrounding vegetation
2. Providing alternative water sources: water from fenced dams can be piped to troughs, however if partial livestock access is needed, hardening an access point (i.e. with stone) can minimise sediment buildup and limit the time animals spend near the water
3. Revegetating around the dam: vegetation will naturally regenerate in fenced off areas; this can be accelerated by planting or sowing wetland and riparian species, especially in isolated areas
4. Varying dam depth: when building or cleaning out a dam, create deep sections for water retention and shallow areas to encourage aquatic vegetation, which helps filter the water and provides wildlife habitats
5. Adding islands and logs: this will offer safe nesting for birds and turtles and create habitats for native fish and other wildlife, such as frogs

These practices help conserve the environment and offer key benefits for farm productivity and emissions reduction. Enhancing water quality and biodiversity in farm dams can lower greenhouse gas emissions, especially methane. A recent study showed that fencing to exclude livestock reduces dissolved nutrients, increases oxygen in the water, and cuts methane emissions by 56%. As such, these simple steps can not only create a healthier ecosystem, but also help farm dams contribute the reduction of  atmospheric warming, for more sustainable and productive farms.

Read more about Enhancing farm dams (Sustainable Farms) and the Farm dams technical guide (Sustainable Farms).

By taking a proactive approach to managing feed and water, farmers can optimise their productivity by ensuring the health and performance of livestock.

Acknowledgement

Thank you to Peter Matthews and Kathi Hertel (NSW DPI), Martin Preuss & Paul Simpson (Murray LLS), Sheree Hamson (Elders) and Clare Crane (ANU) for  speaking on the day. Thank you also to our hosts, The Moll Family and to RAGT for supplying the barbeque lunch.

This event was supported by the Stock Water Management project, which is a Southern NSW Drought and Innovation Hub project funded by the Australian Government’s Future Drought Fund. This project is supporting farmers to create personalised water management plans to more efficiently store and distribute water, and ultimately reduce the impact of drought.