Animal Production Science
Volume 60 Number 1 2020
Australasian Dairy Science Symposium 2018: Dairy Science for Profitable and Sustainable Farming
ANv60n1_FOADSS2018 special edition
AN18579The frontiers of biomedical science and its application to animal science in addressing the major challenges facing Australasian dairy farming
We describe the application of biomedical tools to address issues found in Australasian dairy farming. In particular, the use of small vesicles (40–120 nm) known as exosomes that specifically package, protect and deliver their cargo throughout the body. Exosomes provide opportunities for diagnostics (through evaluations of their cargo) and therapeutics (via specific loading and delivery of their cargo).
The Australasian dairy industry is facing the challenge of increasing productivity while also reducing greenhouse gas (GHG) emissions. This paper reviews the most promising technologies, concluding that substantial GHG abatement is possible, but the industry will need to consider further offsets in trees to achieve carbon-neutral dairy farming in Australia and New Zealand.
The use of mixed ration feeding systems in Australia and New Zealand has increased in the past decade in response to variable climate and market conditions and to enable dairy businesses to be more resilient. This paper reviews the attributes contributing to resilience, namely flexibility, consistency, adaptation, sustainability and profitability with a particular focus on the forage base, milk production responses, the production : cost base and resource management. Potential areas for future work to maintain the resilience of mixed ration systems are also considered.
Forage management underpins the success of pastoral dairy industries. Recent dairy forage research was reviewed through a production and input loss frontier framework along with their potential impacts on competition from non-dairy alternatives, labour and animal welfare challenges. The diversity of approaches to modifying both the production and input loss frontiers will provide the tools for pasture managers to meet future production and environmental challenges.
In this review, we assess how opportunities emerging from microbiome science can help address challenges in the dairy industry, associated with the sustainable production of dairy globally. While the industry is increasingly pushing the biological production limits of dairy cows, microbiome research offers the potential to reduce the impact of dairy wastes on the environment by decreasing urinary N output and reducing emissions of greenhouse gasses.
Every aspect of society and industry seems to be examining the potential benefits from applying artificial intelligence (AI). In the present paper, I examine the likely benefits to agriculture from applying AI and discuss some of the challenges. I identify 21 different areas, with the highest-value capabilities being those where multiple different areas of AI developments are brought together to form new capabilities such as farm robots, digital twins and supply-chain traceability.
Improved efficiency in dairy systems is a significant challenge for the future. Resilient pasture-based milk-production systems have the capacity to thrive within the changing and uncertain global milk-production environment. Such systems, based on high-productivity grassland management allied to genetically elite adapted animal genotypes, are well placed to meet the increasing global demand for food within a resource-constrained environment.
AN19142Water-quality issues facing dairy farming: potential natural and built attenuation of nitrate losses in sensitive agricultural catchments
Water-quality impacts of dairy farming can be significantly reduced by developing tools and practices to design and manage dairy land use and drainage waters. This would include spatial alignment of intensive dairy lands with naturally high nitrogen-attenuation capacity pathways that reduce nitrate losses to sensitive water bodies. Likewise, the development of innovative edge-of-field technologies such as controlled drainage, drainage-water harvesting and re-use, woodchip bioreactors, and constructed wetlands enable the management of critical flow pathways from dairy farming on artificially drained lands.
The notion that nitrogen (N) fixed by clover in mixed grass–clover pastures should lead to lower N emissions to the environment than N supplied as fertiliser is attractive and commonly promoted. However, empirical evidence from published studies shows no difference in N leaching when the same total amount of N is supplied from different sources. We explain why this is so, and conclude that it is the total amount of N entering the system that matters, not where it comes from.
AN18568Identifying current challenges and research priorities to guide the design of more attractive dairy-farm workplaces in New Zealand
Globally, dairy farmers face issues with attracting and retaining high-quality staff. Future management of dairy farms will demand farm teams with flexibility, understanding of consumer and community expectations, and the ability to effectively use technology, only exacerbating the challenge of finding the right staff. The present study used workshops and interviews with experts to examine people-related challenges associated with future dairy farms, and we suggest research and development priorities for the next decade.
Sharemilking is an entry point for new dairy producers in the New Zealand industry, but growing milk price volatility increases the business risks for sharemilkers. We tested the hypothesis that flexible sharemilking arrangements will reduce the income variability of sharemilkers. The results illustrated the feasibility of a flexible model that shifts some of the risk from the sharemilker to the farm owner, while still allowing both to generate a positive return on assets and a positive net profit with high probability.
AN18573A meta-analysis comparing four measurement methods to determine the relationship between methane emissions and dry-matter intake in New Zealand dairy cattle
Respiration chambers enable accurate and precise measurements of methane production and dry matter intake (DMI) from cattle, but this method cannot be used under field conditions. The present study analysed published data of New Zealand dairy cattle on methane estimated by the sulphur hexafluoride (SF6) technique or a GreenFeed automated head chamber, with DMI measured or estimated in the field. The field methods enabled accurate prediction of methane per unit of DMI, but were less precise than respiration chambers.
Reducing the number of milkings to one per day may help the dairy industry to attract and retain quality staff. The aim of this study was to investigate the financial implications of adopting this strategy. Results indicate that profitability could be maintained or increased when expenditure was decreased (e.g. by improving labour efficiency). However, this was not achieved by all farms, highlighting the importance of planning prior to adopting once-a-day milking.
AN18537Grazed chicory, plantain or ryegrass–white clover alters milk yield and fatty acid composition of late-lactating dairy cows
Milk fatty acid profile has implications on human health, processing quality and storage characteristics of milk products. This research compared milk fatty acid composition of cows grazing perennial ryegrass–white clover pasture with that of cows grazing herbs chicory or plantain. Forage herbs demonstrated the potential benefit to alter milk fatty acid composition, while increasing milk production.
Plantain (Plantago lanceolata L.) can be included into perennial ryegrass (Lolium perenne L.)-based pastures to increase the productivity and profitability of dairy farming systems in south-eastern Australia; nonetheless, plantain is often underutilised, partly due to the shorter life span of plantain compared with perennial ryegrass. This research tested the efficacy of different sowing methods (direct-drilling vs broadcasting) in establishing plantain during spring in existing perennial ryegrass-dominated pastures. Both direct-drilling and broadcasting were successfully used to establish plantain in these pastures.
The hunger of the cow prior to consuming supplementary feeds is the most important factor determining the magnitude of the marginal milk-production response to supplement; however, it is difficult to estimate. It has been hypothesised that the level of hunger may be estimated from the post-grazing pasture residual and this study aimed to determine the relationship between post-grazing residual and the marginal milk-production response to supplements. A practical application of the results is that farmers use the change in pasture residuals to determine the provision of supplementary feeds offered, if any.
We applied a structured approach to re-design New Zealand dairy farming, working with a number of stakeholders. With the aim of achieving integral sustainability, we produced two conceptual designs. The sustainability issues the industry is facing are interconnected, so their solutions need to be designed holistically, and the design boundaries need to go beyond the farm gate.
The genetic gain in nutritive characteristics of perennial ryegrass cultivars has not been quantified in dairy environments in Victoria. This work aimed to quantify these improvements, but found that most cultivar differences could be attributed to cultivar maturity and ploidy factors, with little effect of the decade of release. These cultivar differences are likely to be of economic importance at the farm level.
AN18566New Zealand dairy farmers preference investments in automation technology over decision-support technology
Precision-farming technologies are receiving greater attention by researchers and policy makers for potential improvements in farm management. New Zealand dairy farmers have focussed on investment in automation technology in the dairy, some of which provide greater labour efficiency, rather than investing in data-capture technology for decision support. Further improvements in labour efficiency from technology in high-performing conventional dairies may be limited, and adoption of data-capture technologies may need to accelerate to support an increasingly diverse and less experienced workforce.
New technology innovations to acquire pasture growth data continue to emerge in the dairy industry. The potential of remotely accessed data to improve grazing management relies on addressing farmers’ changing information needs. We suggest that providing this data will not result in practice change unless farmers have progressed through a grazing management learning process and come to understand how to use data effectively.
AN18539The effect of perennial ryegrass ploidy and white clover inclusion on milk production of dairy cows
Recent research has reported that perennial ryegrass (PRG) ploidy and white clover inclusion in grazing swards can have a positive effect on milk production. In the present study, cows grazing PRG–white clover swards had greater milk yields than did cows grazing PRG-only swards, while grass ploidy had no effect. This significant increase in milk production from PRG–white clover swards suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production.
AN18569Effect of weather on activity and lying behaviour in clinically healthy grazing dairy cows during the transition period
Lying time is a high-priority behaviour in dairy cows and electronic monitoring of lying behaviour is of interest in grazing systems. The aim of the present study was to determine the effect of inclement weather on the modification of lying behaviour in grazing dairy cows. There appears to be a direct thermal effect associated with behaviour in dairy cows exposed to brief periods of inclement weather. Researchers should consider climatic factors when interpreting changes in behaviour in grazing dairy cows.
AN18544Preliminary assessment of the ability of detainment bunds to attenuate sediment and phosphorus transported by surface runoff in the Lake Rotorua catchment
The present study investigated the ability of a detainment bund to mitigate sediment and phosphorus losses from pastoral agriculture. The performance of this mitigation strategy, which temporarily ponds storm-generated surface runoff for 48–80 h on productive pasture, has never been quantified. Results of the study suggest that this detainment bund is effective at attenuating suspended sediment and phosphorus, although further research should be conducted before promoting detainment bunds at a wider scale and before land managers make substantial investments.
Increasing milk-price volatility is requiring a re-focus of research interests on efficiency of milk-production systems. There is a significant scope to increase efficiency on pasture-based dairy farms. Reducing costs and increasing profitability per unit of the most limiting resource (e.g. land) will ensure the dairy business is resilient.
AN18532Predicting milk fatty acids and energy balance of dairy cows in Australia using milk mid-infrared spectroscopy
The present study demonstrated the potential of using mid-infrared spectroscopy of milk samples for predicting milk fatty acids and energy balance of dairy cows in Australia. Using a comparatively small dataset of 240 cows from a single research herd, the results showed that milk fatty acids were accurately predicted, while the prediction accuracy for energy balance was moderate.
Dairy farmers in pastoral systems face several risks, including price volatility. Farm data were used to understand how to be profitable and able to withstand these risks. We concluded that maximising pasture harvested, and minimising reliance on supplementary feed, and effective cost control (minimising expenditure) are the key factors that lead to profitable businesses that are also resilient to the low milk prices that occur in a volatile market.
AN18535Defoliation dynamics, pasture intake and milk production of dairy cows grazing lucerne pastures in a partial mixed-ration system
Grazing-management strategies within high-intensity dairy systems have significant impacts on intake, production and profitability. Traditional grazing strategies aim to utilise high proportions of lucerne pasture, forcing cows to graze down into the lower-quality stemmy portions of the pasture sward and, consequently, reduce dry-matter intake and milk production. Managing pasture allocations to ensure that an area of the paddock remains ungrazed ensures that cows graze only the top leafy portion of the pasture, which significantly increases diet quality, total dry-matter intake and production.
AN18578Prediction of quarter level subclinical mastitis by combining in-line and on-animal sensor data
The present study investigated the ability of electrical-conductivity (EC) data, combined with data of activity and rumination changes, to detect automatic subclinical mastitis (SCM). Through logistic mixed modelling, we found that EC in combination with activity and rumination information can improve the prediction of SCM in automatic milking systems, compared with EC alone.
White clover can improve herbage dry matter production in grass-based milk production systems. This study investigated the persistency of white clover under a high N-fertiliser application level and at a high stocking rate. White clover inclusion initially increased herbage DM production under these conditions; however, the initial extra herbage DM production on grass–clover swards decreased each year.