through associative effects in digestion. It is possible that higher sugar grasses could lead to greater diurnal fluctuations in rumen fermentation and an increased incidence of sub-acute acidosis in some feeding systems leading to lower than expected ME available to cows. Furthermore, it is also possible that increases in the soluble sugar concentration in grasses may lead to altered fermentation pathways that have implications for milk composition and functionality and greenhouse gas emissions. Commonly used nutrition models, for example CPM Dairy, would not be suitable for examining such impacts as they work on a daily time step, whereas it is the intake pattern and the amounts of pasture and supplements ingested that will determine the diurnal fermentation pattern and incidence of sub-optimal fermentation. More sophisticated models (e.g. Molly) require further development for use in pasture-based systems. The benefits (or otherwise) of new germplasm with altered nutritive characteristics are likely to differ between the five broad feeding system categories used by the industry.
The modelling of the three-way inter-relationship between Feedbase and Animal Nutrition, Natural Resource Management & Climate Change, and Animal Performance priorities are likely best dealt with in the design of Dairy Futures CRC Program 3 (Capturing the farm, factory and community benefits).
Comments:
The potential impact from new germplasm is high providing benefits can be captured at farm level. Until new germplasm is available and preliminary evaluations (in pot or plot work) are completed, it will be difficult to evaluate the benefits through modelling or field evaluation approaches. The timing of availability of new germplasm is not clear to the author.
The inter-relationships between plant breeding, agronomy, animal nutrition, animal genetics and natural resource management are likely to be
examined through modelling as part of the scoping of Program 3 of the Dairy Futures CRC or by commercial partners. It will be imperative that the right mix of disciplinary and practical skills is involved in evaluating the benefits in different systems.
6.4. Animal genetics and
reproductive performance
There is a key overlap between animal genetics, reproductive performance, and NRM&CC through N excretion and methane emissions intensity. Animal Performance RD&E Priority 1 (Breeding herd that perform in Australian Conditions) and Priority 2 (Improve capacity for genetic improvement through genomic and reproductive technologies) both have the potential to significantly impact emissions intensity, overlapping the NRM&CC Priority C (GHG emissions).
Animal Performance Priority 2 (Theme 2: Extending genomic Australian breeding values to new and valuable traits) includes genomics research to improve breeding values and markers to new traits (for example feed conversion efficiency and fertility) that will impact enteric emissions and national greenhouse gas abatement strategies.
In addition to leading the development of new and valuable traits, the Dairy Futures CRC Program 3 will be used to determine further opportunities to reduce enteric methane emissions. It is likely the approach taken will be dependent on the trait. For example, the benefits of selection for fertility in different farm systems might be examined using modelling, while the benefits of improved feed conversion efficiency (FCE) might require modelling and experimental work. For example, if the, then it is likely modelling would be conducted to examine the impacts on production and environmental expression of high versus low FCE in young animals is confirmed when they are lactating and fed partial mixed rations benefits in different farm systems. It is also likely that controlled research might be required to examine whether expression of high FCE is maintained in other feeding systems and whether it is associated with feed intake, digestion or tissue metabolism. Such investigations of the biology might enable better targeting of genetics to different feeding systems or provide opportunities to take advantage of the unique biology.
Transition feeding has an important role in animal reproductive performance and is reflected in the interdependency of the Animal Performance Priority 1 (Theme 2: Improving reproductive performance) and Feedbase and Animal Nutrition priority (D2: Improved transition cow diets and management pre and post calving for higher production and improved cow health and reproduction).
A recent review undertaken by Dairy Australia’s
Grains2Milk and InCalf programs of the current Australian literature and practices to identify key principles/
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s-linkages betw
een priorities
cow through management of the transition period has recently been completed by Ian Lean and Peter DeGaris. This has produced best practice management procedures that combine animal nutrition advise to nutritional professionals, veterinarians and farm advisers and will be incorporated into the InCalf fertility modules outlined in the Animal Performance Priority 1 (Theme 2: Improving reproductive performance).
Also envisaged in the priority was new research to quantify milk production benefits (independent of disease reduction) from better pre- and post calving nutrition and develop cost-effective methods of capturing these production benefits and those from improved health and reproduction. This research links to that proposed in Feedbase & Animal Nutrition priority activity (D1: More efficient utilisation of N and carbohydrate from feed sources for optimised FCE and milk protein + fat production)
Comments:
The potential impact from improved animal genetics is high providing benefits can be captured at farm level. Scoping activities at the Dairy Futures CRC are being conducted to establish priorities for future work in particular capturing the benefits offered by improved breeding values and markers. This indicates these scoping activities should inform future investment decisions. The inter-relationships between animal genetics, nutrition (inc feedbase), health and natural resource management are likely to be examined through modelling and it will be imperative that the right mix of disciplinary and practical skills is involved.
Improved reproductive performance impact herd profitability and natural resource management outcomes and are effected by nutritional and animal management practices. Good collaboration exists between nutritional and Animal Performance programs, but greater interaction with natural resource management programs should be developed.
6.5. Dairy Cow Nutrition
There are numerous overlaps between the feedbase, cow nutrition and cow genetics, management, health and welfare and natural resource management issues related to greenhouse emissions. The need for research in nutrition is justified by the conflicting beliefs amongst scientists and nutrition advisers as to the nutritional principles that apply in grazing systems, particularly the systems using higher amounts of supplements. This has left dairy farmers generally confused in relation to what they should believe.
Priority D1 (More efficient utilisation of N and
carbohydrate from feed sources for optimised FCE and milk protein + fat production) of the Feedbase and Animal Nutrition strategy drives specifically at how to improve the efficiency with which feed is converted to milk across all dairy farm systems. This challenge is complex, particularly in systems where grazed pasture or forage is a significant component of the diet, and, hence in practice, is usually in separate meals to supplementary feeds.
Research into understanding how positive associative effects between feeds can be captured and negative associative effects can be limited is integral to improving feeding system efficiency, but it is also complex and expensive. A better understanding of issues such as:
› The impacts of different combinations of grains with different rates of fermentation and rumen retention times for high vs low producing herds/cows in different systems;
› The interactions between different feed combinations and stages of lactation; and
› The effects of different fibre sources on rumen retention times.
An understanding of these issues have the potential to deliver significant productivity improvements on farms. A common element to many of the nutrition questions is how to optimise rumen function in relation to ruminal starch and fibre digestion and microbial protein production.
Development of a research and development program in nutrition needs to consider carefully the practicalities (complexity and feasibility) of such research. It will be important the integrity of experiments is not compromised by trying to answer too many questions. This said it may be possible to examine linkages to animal health (Animal Performance) or methane emissions (NRM&CC) and nitrogen excretion (NRM&CC) without compromising experimental design as is being done in the flexible feeding systems research at Ellinbank.
This priority (D1) is also linked to priorities B2 (Improved strategic, tactical and operational decisions in relation to how particular forages fit in the feed production and feeding system on farms) and C2 (Application of more ‘sophisticated’ characterisation of feeds to improve efficiency of conversion of nutrients to milk protein + fat) in the Feedbase and Animal Nutrition strategy.
Comments:
The impact of improved knowledge in nutrition would be high.
This area of research and development is complex and sound experimental design is critical to success. In developing the detailed research plans it might be possible to value add through the measurements taken in experiments (e.g. animal health, milk composition and functionality, FCE, grazing management, methane and nitrous oxide emissions). However, integrity of the research is paramount to removing conflicting beliefs amongst scientists and nutrition advisers.
Requires a belief the cost of fundamental research will return value to the industry.
6.6. Access to data
The establishment of a centralised data repository was recommended in the Animal Performance Priority 4 (Investigate novel approaches to improve farm productivity via animal performance) to improve on- farm decision making, and improve data for research and development programs. These outcomes closely align with Feedbase and Animal Nutrition outcomes of Priority E (More effective tactical and strategic management decisions through timely, accurate and objective measurement of farm resources)
There was a desire expressed, particularly in the Animal Performance strategy, but more broadly at the program managers meeting, to capture much more detailed data from farms on feeds and feeding, animal performance (e.g. fertility) and management (e.g. transition cow feeding and management) and on the decision making process. It was envisaged there would be farm and national benefits that could be gained from an integrated data base which would link into a modelling capability, enabling better decision making.
In the Animal Performance strategy it is indicated the National Herd Improvement Association has been investigating the value proposition for improving data collection, quality and quantity, transfer and access in the Australian dairy industry. Other Dairy Moving Forward activities concerned with data collection include the Farm Business Management Strategy 2 (Good Tools – To ensure good quality ‘tools’ are used effectively and appropriately).
Comments:
Discussions between those involved in data collection and analysis may identify an approach to improve data collection, storage and access. The author is not in a position to comment on the likely value or costs.