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Agronomy Network Meeting 3: Water, Nutrition and Feedbase Change

Agronomists, service providers and researchers in feedbase came together in Moama in March for the third workshop in a series provided by the Accelerating Change project. The series is designed to strengthen relationships across the dairy industry, enhancing collaboration and capability in all areas of feedbase, providing participants with a range of information they can use to support dairy farmers in a changing environment.

The focus of the March workshop was to give participants a better understanding future water availability for dairy farmers in the region, changes to feedbase, and dairy cow nutrition. Bringing these topics together at the end of the workshop, attendees were asked to help identify research, development and extension priorities for what they believe are required to support future feedbase systems.

The Socio-Economic Impacts of the Murray Darling Basin Plan

Claire Miller, Dairy Australia’s Manager of Policy Strategy, presented the findings from several research projects on the socio-economic impacts of the Murray Darling Basin Plan in northern Victoria and southern NSW. These included the Aither report for Dairy Australia, Water Market Drivers in the southern MDB: Implications for the dairy industry (29 July, 2016); the RMCG report commissioned by the GMID Water Leadership Forum, Basin Plan: GMID socio-economic impact assessment (Sept 2016); and the Dairy Evaluation of the Goulburn Broken CMA’s Regional Irrigated Land and Water Use Mapping in the GMID (2017), developed by Murray Dairy and Dairy Australia. Claire highlighted the need for change in dairy systems to be able to respond to a changing operating environment, including changes to policy and climate which have impacted on water availability and price, growing conditions, commodity markets, and variability in the cost and availability of other business inputs.

Milk production has been shown to be closely linked to water availability and affordability, which makes it no surprise that water is a key focus and a driver of decision-making on dairy farms. Water buybacks have reduced the irrigation pool in the southern basin by an average of 15 percent a year, most significantly from Victoria, which has seen a 41% decrease in high reliability water deliveries (from 2000GL to 1200GL). As a result, temporary water costs are estimated to have increased $14-$36/ML in average year, and $24-$49/ML in a dry year. Over 70 percent of the dairy farmers in the GMID indicated that they owned less water than required for irrigation, relying on the temporary market to meet any gaps and leaving them exposed in dry years. Of those farmers, 26 percent indicated that temporary water prices in excess of $150/ML are not viable for their business, and 56 percent indicated the same for prices above $200/ML.

The service providers in attendance indicated that, as a result of these conditions, they are seeing varied changes to feedbase on dairy farms, some seasonal and others more permanent. The service providers noted that the extent of these changes varies significantly between farms but thought they were influenced considerably by water ownership and equity, stage of business development and subregion.

They indicated that farmers across the region are increasingly using mixes of grazed and conserved feed in partial and total mixed ration systems, not only to supplement but, in some cases, to substitute for grazed fodder. On a seasonal basis the move to PMR and TMR systems seems to be driven by temporary water price which, in a summer like the one experienced in 2015-16 where average temporary water price exceeded $250/ML (which over 80% of dairy farmers considers unviable), can lift the cost of production of grazed pasture beyond the price of bought in or conserved feed. Service providers commented that they are noticing many dairy farmers looking to conserve feed as a risk management strategy and making an effort to build relationships with grain and hay suppliers to increase certainty around feed supply.

They are also seeing farmers across the region moving away from perennial pasture dominant systems to those that use annual forages, more summer active species, legumes, cereals and crops in an effort to produce more feed with less irrigation water. Although most still rely on irrigation, some agronomists indicated that they knew of dairy farms introducing dryland legumes and crops into their systems.

There was mixed feeling about farmers’ willingness and capability to change their feedbase systems, and whether changes were short-term coping mechanisms or longer term strategic decisions. As expressed by the agronomists, it is hard to set goals when the goal posts are moving. Research presented by Claire showed that 64 percent of dairy farmers in 2015-16 said they were disinclined to change their practices due to ‘uncertainty of water allocation’. Agronomists indicated that they knew of farmers who, as a result of the season and market variation in the last 12 months, would move away from perennial pasture entirely, but others who would revert to a perennial pasture-dominant system with low water prices forecast for the next season.

This discussion brought up questions around the way forward for feedbase and investment for changing systems. Whilst some farmers are looking at investing in land, others are looking at investing in infrastructure or high reliability water entitlements. Others, the agronomists felt, are financially restricted in terms of their ability to make any significant investment at the moment, making them vulnerable to increases to water price or other commodities in the near future.

Murray Dairy’s Accelerating Change project is working to address gaps in RD&E around future feedbase systems. The project is currently looking at the performance and value of different forage types on its project Partner Farms across different seasons. To support better feedbase and irrigation management, the project has rolled out a series of cropping workshops, soils workshops, and an irrigation technology trial. It has also developed a Service Provider Network to improve sector knowledge, communication and collaboration. Accelerating Change has also identified the need to build strategic planning and risk management into dairy business models and is developing a strategic business planning program to kickstart this process. It will also develop a case-study based Flexible Feeding Systems project, looking at investment options for building seasonal flexibility and resilience into feedbase systems.

For a copy of Claire's presentation, click here.


Lisa Birrell, Murray Dairy’s Regional Extension Officer in Feedbase and Animal Nutrition, presented on cow nutrition, highlighting the considerations that nutrition should play on agronomic decision making.

Feeding is all about balance. Lisa emphasized that nutrition should focus on supporting microbial activity in the rumen. Protozoa, bacteria and fungi break down feed to supply energy and protein to the cow. These rumen bugs are highly sensitive to abrupt diet changes and require time to rebalance pH and microbe populations that support digestive capability when feeding habits are altered.

During feed planning it is important to consider transitions, rations, diet balance, herd composition and cow activity. There are many indicators on farm to help you evaluate and adjust the diet – from milk quality to cow behaviour – make sure you continue to monitor these indicators and make adjustments as necessary for optimum production.


Water is required by dairy cows for:

  • Temperature regulation

  • Nutrient transport (through the blood system which is 80% water)

  • Chemical reactions and digestion (in the rumen where water supports the mixing of feed, dissolves nutrients and drives chemical reactions)

Water needs for a cow are included in the below table. Green feed contributes some water to the diet but will not entirely meet a cow’s needs. When planning rotations and allocations think about where water troughs are situated.


The rumen bugs aren’t mobile, so strong rumen contractions are required to get good mixing of feed and bugs. Fibre (ie what you can’t bend between your fingers) tickles the rumen walls and makes the rumen contract that promotes good mixing of food and bugs. Signs that cows may be lacking some fibre include:

  • Very loose manure

  • < 50% of resting cows actively chewing their cud

Milk Fat

Milk fat comes not only from the diet but also from De Novo fatty acid synthesis in the udder. At certain times of the year (often winter) milk fat percent can be lower than protein test. This can occur due to the shutting down of the biochemical pathway for linoleic acid to become conjugated linoleic acid (you get incomplete isomerisation). This prevents milk fat being synthesised in the udder so the milk fat test only comes from the diet. As long as the protein test is stable, cows are chewing their cud and still producing well, the cows aren’t sick. If protein test and milk production starts dropping then the cows are at huge risk of suffering acidosis (low rumen pH) and need to be removed from the pasture and hay added immediately to the diet. For more information on milk fat depression, see Dairy Australia’s factsheet.

Nitrogen Fertilisers

Lisa also discussed considerations for cow health in the application of nitrogen fertilisers. Although high levels of nitrate are good for plants, they are not for cows. Nitrate is broken down in the rumen to nitrite and then ammonia, which can be utilised by the cow. Signs of excess nitrate in a cow’s diet include ammonia smell in the dairy and urine scalds in the paddock.

Nitrate levels are at their highest in plants 7-16 days following a nitrogen fertiliser application. There are several ways to avoid this period or to reduce the impact of nitrate in grazing cattle.

  • Nitrogen can be applied to an entire area, with cows put onto the pasture immediately following the event. Cows are then able to adjust to the increasing levels of nitrate being absorbed by the plants, and becoming a part of the diet, over time.

  • This strategy will inhibit the use of nitrogen in the plants that are grazed early by removing leaves in which the nitrate is stored. Agronomically, it is not an effective option.

  • Alternatively, you can graze prior to application or after the eighteen day mark.

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