Moorepark ’23: Current and future technologies to meet sustainability challenges

Irish dairy farming has undergone a transformation during the last 10 years. Up until 2015, there had been 31 years of the EU milk quota regime, which stifled innovation. Since then, there has been significant expansion due to the pent up capacity in the industry.

Attendees at today's Moorepark Open Day heard that the next phase of development will have to be based on the principle of decoupling greenhouse gas (GHG) and nitrate (NO₃) emissions and nitrogen loss from production, while advancing the quality and quantity of enriched areas on-farm.

Laurence Shalloo and Siobhan Kavanagh, Teagasc, and Deirdre Hennessy, UCC, explain that all of this is possible and will be the focus of technologies that are introduced onto farms in the coming years. This will all occur at a time when there is increasing investment in research for new solutions and will provide the platform for even greater ambition around sustainability at farm level.

In the below video, Laurence and Deirdre discuss the sustainability challenges facing dairying and they detail current and future technologies available to meet them:

Current technologies 

Policy changes at both national and EU level will require a greater focus on a wide range of sustainability metrics at farm level. The main policy challenges include changes to the Nitrates Directive, biodiversity regulations and greenhouse gas emissions targets. Along with these, a special focus must be continual placed on a number of impact categories including: cow and calf welfare; carbon footprint; ammonia emissions; and water quality and footprint.

There are many currently available technologies that can be immediately implemented by farmers that will have positive impacts on sustainability. These technologies are discussed across the impact categories. In most cases, they will not increase costs at farm level and in some cases these measures would help reduce costs and increase profitability.

Cow welfare

Achieving continued improvements in cow welfare requires a focus on farm management, infrastructure and breeding:

• Roadways should be well maintained and upgraded where required. Locomotion scoring of dairy cows should be conducted regularly to pick out cows with suboptimum mobility, which will aid early detection of lameness problems.
• Ensure winter accommodation is suitable with appropriate space allowances.
• It is essential that every dairy herd has a ‘herd health and welfare programme’ as an essential part of the management system. The EBI, including the emphasis on the health and fertility sub-indices, should be used to identify bulls that are suitable for a pasture-based system.

Calf welfare

Adopting correct calf management practices are critical to ensuring healthy, well-grown calves. Management during the pre-weaning period has implications for subsequent animal health and welfare, and also for subsequent productivity and longevity.

When the calf is born, attention needs to be paid to colostrum management and ensuring the calf receives a sufficient volume (3 litres) of high quality colostrum (>50 mg per ml IgG) within the first two hours of life is critical to achieve passive transfer of immunity. At least four feeds of transition milk should follow the initial colostrum feed before the calf moves to high quality whole milk or milk replacer.

Calves should be fed three litres of milk twice daily for at least four weeks of life. Fresh water and concentrate should be made available from birth with the aim of encouraging rumen development.

Milk volume can be reduced to four litres and fed once daily from four weeks of age, to promote increased concentrate intake and ensure a smooth transition between the pre- and post-weaning periods.

When weaning, calves should be weaned gradually to minimise post-weaning reductions in growth rate and to maintain good health and welfare. In addition, the housing environment should allow calves perform to their maximum ability with minimum disease risk, and positively influence the health, growth, development and general welfare of the calf.

Greenhouse gas emissions

The Marginal Abatement Cost Curve (MACC) (Version 3 to be published in July 2023) has identified the most cost-effective pathway to reduce sectoral emissions. The adoption of measures such as reducing our reliance on chemical nitrogen fertiliser, a change of nitrogen fertiliser type to protected urea, using high EBI and high DBI genetics, use of sexed semen, improved animal health, extending the grazing season, and use of white clover are critical to reducing sectoral emissions. Initially, our focus must be on reducing our reliance on chemical nitrogen fertiliser.

• There are a range of proven technologies to reduce reliance on chemical nitrogen fertiliser:
• Correct soil fertility. Moving from pH 5.5-6.3 can increase soil nitrogen availability for grass growth by between 50-70 kg nitrogen per ha per year, as well as reducing nitrous oxide emissions per kg nitrogen applied. Target soil Index 3 for phosphorus and potassium for optimum sward nutrition.
• Apply slurry using low emission slurry systems (LESS; e.g. trailing shoe, band spreading) between February and May. The nitrogen fertiliser replacement value of slurry can be increased (25%-50%) by using LESS instead of splash plate and ammonia emissions are reduced.
• Incorporate white clover on farm. White clover can fix between 80–120 kg nitrogen per ha per year depending on underlying soil fertility and sward management.
• Use red clover for silage to significantly reduce the requirement for chemical nitrogen fertiliser on silage swards.
• Where chemical nitrogen fertiliser is used, switching from CAN and straight urea to protected urea will directly reduce both GHG and ammonia emissions, while also being cheaper per kg nitrogen applied.

Ammonia emissions

There are a range of options to reduce ammonia emissions on dairy farms. These include reduced crude protein in concentrate feed, use of protected urea instead of ordinary urea or CAN, as well as the use of LESS technology for the application of animal manures. At dairy farm level, the two measures responsible for the vast majority (circa 80%) of the ammonia emission reductions are using protected urea and LESS:

• Protected urea will reduce greenhouse gas and ammonia emissions compared with CAN and straight urea.
• LESS technologies such as trailing shoe and band spreading results in greater retention of the nitrogen in the slurry within the system.

Water quality

The Teagasc ASSAP programme is designed to enable landowners to engage positively in seeking solutions to local problems in relation to water quality through the support of a confidential sustainability advisory service focused on water quality improvement. Contact your local ASSAP advisor and book a consultation. Three key actions have been identified:

• Reduce phosphorus and sediment losses. Use ‘break the pathway’ measures to prevent run-off overland into the drainage networks. For example, targeted riparian margins and buffer margins, use of low earthen mounds, planting of trees and hedgerows, prevention of livestock access to water, wetland ponds, careful management of critical source areas and sediment traps.
• Reduce nitrogen losses. Ensure soil fertility is optimum for P, K and pH, take soil samples and follow a nutrient management plan. Apply fertiliser/slurry when soil temperature, soil moisture content, growth rates and weather forecast are suitable particularly in the early and late growing season. Quantify the nitrogen surplus on your farm and take measures to reduce the surplus that is available to be lost to water.
• Ensure that your slurry, soiled water, dairy washings, silage effluent and farmyard manure collection and storage facilities meet requirements. Make your contractor aware of the locations of critical source areas, watercourses, drains, etc. on your farm. Ensure appropriate buffers zones are kept when spreading organic manures.

Biodiversity

Biodiversity management on-farm involves retaining, enhancing and creating habitats. It is important to optimise the biodiversity value of existing farmland habitats before new biodiversity measures are established.

• Do not top escaped hedges, side trim only. The biodiversity value is in the canopy and in bank and ground vegetation.
• Side trim topped hedges from a wide base to a triangular profile. Cut the growing point to prevent escaping, leaving the peak as high as possible. Retain occasional thorn saplings and allow them to mature into flowering and fruiting trees.
• Maintain riparian buffer strips. These are strips of permanent vegetation adjacent to rivers and streams that are typically excluded from intensive farming practices. Appropriately managed buffer strips play an important role in maintaining water quality, ensuring bank stability and providing a habitat for biodiversity.
• Quantify the biodiversity enriched area across the overall farm, and develop a plan to increase biodiversity across the rest of the farm.

Future technologies to increase sustainability

New technologies are currently being developed/researched. In time, these will further increase the sustainability of the dairy industry.

Cow health and welfare

Recently published Moorepark research highlighted links between reduced lameness and reduced SCC associated with genetic selection (i.e. better EBI). In the future, it is anticipated that there will be greater emphasis on health traits in the EBI as other issues become less of an issue. For example, a recent study indicated that animals with greater genetic merit for TB resistance are less likely to test positive for TB even though their herd mates may test positive.

Data from ICBF indicates that herd replacement rate has declined from 23% in 2013 to 19% in 2022. At the same time, the number of recycled cows in the system has reduced from 16% to 11%, while difficult calvings has declined from 1.8% in 2013 to 1.2% in 2022. The focus will continue to remain on a pasture-based system with a long grazing season with grazed grass constituting the majority of the dairy cow diet and not on milk yield per cow.

It is anticipated that there will be a substantial growth in the beef-cross offspring coming from the dairy herd, facilitated by increased use of sexed semen. Teagasc Grange research has reported that when Angus calves are compared with Holstein Friesian calves, the Angus calves finish at an earlier age and have a higher carcass value, resulting in both reduced costs of production and higher output.

Every spring, there is a period when there is greater calf supply to the market than demand for calves. There are a number of strategies that affect both the supply of calves to the market and the demand for calves. These include increasing the profit potential of the calf, developing profitable production systems for early maturing dairy calf-to-beef, developing and maintaining high welfare animal transport systems that allow calves to move to mainland Europe, investing in labour efficient calf-rearing systems that will facilitate calves remaining on farm, if required, for longer periods, as well as dairy and beef farmers developing relationships that facilitates a model that is beneficial to both parties.

The newly developed Commercial Calf Value (CBV) tool will provide the communication mechanism around dairy-beef calf potential profitability.

Greenhouse gas emissions

There is a significant programme of work underway in GHG emissions research that has the potential to markedly reduce the emissions profile from agriculture, as well as providing solutions to reduce emissions at farm level.

Enteric methane is estimated based on models that were developed based on international emission factors for methane. Research conducted in recent years across several research groups in Ireland indicated that the emission factor for enteric methane for Ireland is over-estimated.

Table 1 summarises a number of published studies quantifying enteric methane using different techniques between 2010 and 2023. The studies indicated enteric methane emission factors as a percentage of gross energy intake ranging from 4.9%-6.78%. The most recent study, which lasted for more than seven months of the lactation: found that enteric methane emissions were extremely low in the spring, <4.8% of gross energy intake, and then increased as the grazing season progressed.

The seasonal pattern of enteric methane emissions within pasture-based systems requires further investigation to increase the understanding of enteric methane emission profiles. A number of studies recently completed suggest that the emission factor used when animals are indoors on grass silage also over-estimates the enteric methane emissions.

Table 1: Enteric methane measurements across a range of studies carried out with grass in Ireland

Previous studies have reported that increasing EBI results in a reduced carbon footprint but does not result in reduced total emissions. This analysis was completed using models that simulated herd performance. The modelling simulated that enteric methane increased when milk yield increased. When enteric methane emissions were measured in individual cows, however, high EBI cows had similar daily enteric methane emissions to lower EBI cows even though they produced higher milk yield (Figure 1). This means that as EBI increases, the emissions factor should decline to reflect the actual methane output by the animal.

Figure 1: Graphs showing a) milk solids yield, b) methane emissions and c) the proportion of methane emitted per unit of milk solids for the high economic breeding index (EBI) (blue lines) and national average EBI (orange lines) dairy cows across the experimental period

Grass quality and seasonal profile

The results presented in Figure 1 show that there are significant seasonal effects associated with enteric methane emissions from dairy cows. Increasing our understanding of these factors will potentially allow manipulation of grassland management and grass breeding to facilitate the development of strategies to reduce enteric methane emissions from cows consuming pasture-based forages.

Feed additives

There is considerable research being conducted nationally and internationally on the use of feed additives to reduce enteric methane. Significant progress has been made internationally in recent years with products like Bovaer produced by DSM achieving reductions of up to 30% in enteric methane emissions in a TMR feeding system. This product is less effective when pulse fed through the milking parlour and therefore requires further work for effective use in pasture-based systems.

Other products such as the red seaweed, Asparagopsis, has shown great promise in studies completed to date. Other products like Halides are also showing significant promise in terms of reductions in enteric methane emissions.

An important consideration for widespread use of any supplement to reduce enteric methane will be the ability to produce the material in large volumes with consistent amounts of the active material. Other important features include the absence of residues, a mechanism to feed the product to the animal, a mechanism for counting the emission reductions through the national inventory, and that the products do not have a negative effect on performance. It would also be desirable that the supplements are low cost, of natural origin, and can be combined with other solutions.

Carbon sequestration

Carbon emissions from grassland are part of the land use and land use change sector. Current estimates of carbon sequestration in grassland are based on Tier 1 emission factors, which are international default values.

There is currently a significant research programme being undertaken to develop country specific emission factors for Irish soils. Further research is being developed to enhance the activity data around land use and land status. This will be enriched with emissions data from hedgerows to generate national emission removals. It is anticipated that when this research is complete, the combined effects of more accurate country specific emission factors and activity data will present a very different picture regarding emissions removals.

Warming effect associated with GHG emissions

The scientific discussions in the area of additional warming effects associated with biogenic methane and its lifespan is now very clear. Research findings indicate that when biogenic methane is first stabilised and then reduced that all additional warming effects can be removed.

Further and faster reductions in methane would result in a reduced warming effect (reduction from the historic warming effects). It is possible, however, that agriculture and the land use sector could be in a position to not be contributing to increased warming before 2040.

This would require that biogenic methane is first stabilised and then reduced, changes to the land use land use change emissions associated with updated metrics, activity data, technical changes at farm level, and the development and deployment of new solutions at farm level around N₂O.

Water quality

Analysis carried out of the 5th Nitrate Action Programme coupled with increased ambition in fertiliser nitrogen reductions in the Food Vision strategy, would result in a reduction in nitrate-N leaching of between 5.9 kg per ha (circa 10%) and circa 9 kg per ha (circa 18%), depending on modelling approach used.

Reducing organic nitrogen per ha from 250-220 kg nitrogen per ha will only reduce nitrate-N leaching by between an additional 2.2 kg nitrogen per ha or 3.5 kg nitrogen per ha depending on modelling approach used, but it will have a significant financial impact at farm level. Consequently, in order to ensure that the overall approach is robust, a sequential approach to firstly allow the impact of the 5th Nitrate Action Programme and the additional fertiliser reductions in the Food Vision Dairy Group Report to be assessed before introducing any reduction in organic nitrogen limits would be desirable.

This article was adapted from the Moorepark ’23 Open Day book. To access this full paper or for more information from this open day, click here.