Nutritional strategies to reduce emissions from dairy cattle

Feeding dairy cattle to meet the exact requirements of each cow or group of cows is a strategy that helps reduce greenhouse gas emissions, especially methane and nitrous oxide, by improving feed efficiency and minimising waste.  

Supplying the optimal level of nutrients – without exceeding or falling short of an animal’s requirements – will improve feed conversion ratios and overall returns. This is often referred to as precision feeding. Precision feeding can be as simple as calculating the quantity of feed required or as sophisticated as computer-controlled feed mixers.

Precision feeding uses data and monitoring tools to customise rations that:

• Match nutrient supply to the cow’s specific requirements (based on age and stage of lactation etc.)
• Reduce overfeeding of nutrients like protein and energy. Feeding more than an animal needs is costly and has a negative impact on the environment
• Maximises feed conversion efficiency

Even if your farm is already technically efficient, you can probably still make improvements to lower GHG emissions and increase profits.

1. Overfeeding protein, for example, results in more nitrogen going back onto grassland, which, considering many farmers are in nitrate vulnerable zones, is not ideal. It will also increase emissions from slurry. In addition, protein supplementation, specifically soya, carries a significant indirect land use change carbon cost.
2. It may be more cost effective and better for the environment to replace purchased protein with home-grown crops, such as high-protein legumes. Lucerne and red clover, for example, are both naturally higher in crude protein than maize and grass silage.
3. Focus on better-quality, lower-fibre forage to improve rumen fermentation and encourage better feed intake. Improving feed intake will increase yields and reduce methane emissions for each litre of milk produced.
4. Less fibrous forage is more digestible and, therefore, results in less methane being produced. Aim for a digestibility value (D-value) of 70–75. Rations containing maize also tend to result in reduced methane production, largely due to the high starch levels (up to 30%).
5. Grazed grass is more digestible than silage and has a reasonably high polyunsaturated oil content, both of which are also associated with reduced methane production.
6. Tailoring diets to animals’ needs will also benefit their health, for example by preventing metabolic disorders such as ketosis. This will avoid unnecessary costs associated with treating or culling sick livestock and mitigate associated emissions.
7. Precision feeding requires accurate data and there are many tools and resources available to capture this and help calculate your rations. Some of these tools can be expensive, so it is important to make sure you choose the right approach for your farm.

Some systems only require an investment in time e.g. to work out feed requirements, reformulate rations and monitor changes, but others require financial investment, e.g. for software subscriptions, computers and equipment.

• Work with a nutritionist or feed adviser to formulate diets that meet specific nutritional needs for cows by production stage (e.g. fresh, peak, late lactation, dry)
• Use feed analysis and software to balance rations accurately
• Integrate automated feeding systems for individual cow delivery (where feasible)
• Analyse forages and grazed grass for quality to assess digestibility and nutrient value — use services from members of the Forage Analytical Assurance Group (FAA)
• Aim to feed high-quality, lower-fibre forage that will improve rumen fermentation and encourage better intakes
• Focus on feed ingredients that reduce emissions such as home-grown high D-value forage as well as co- and by-products
• Monitor cattle performance (intakes, milk output, and body condition) and adjust rations accordingly
• Reduce your reliance on purchased protein
• Feed additives that inhibit methane production (e.g. 3-NOP) are also an option that can be considered

Supplying farmers with tools to remotely manage grassland, without having to walk fields and measure grass.

This project is investigating modelling future grass growth using cloud-penetrating satellites and AI to enable farmers to plan their grazing requirements more strategically.

Unlocking environmental and economic benefits for the dairy sector through novel additives from a scalable daffodil opportunity.

This project is developing and establishing a UK-based supply chain for a naturally sourced methane-reducing feed additive. The additive – an alkaloid extracted from daffodils – can create a safe and ruminant-friendly product. Preliminary data estimates that this alkaloid can reduce methane emissions and enhance feed protein efficiency by 50%.