Feed management strategies to reduce emission from sheep

Feed management strategies to reduce emissions from sheep.

Getting flock nutrition right is not only vital for sheep performance, health and the bearing these have on business profitability, it has a pivotal role in greenhouse gas (GHG) emissions.

Alongside management, husbandry and genetics, improvements in nutrition can minimise the environmental impact of sheep farming.

Emissions will vary depending on the system and farm type. Lowland farms, for example, tend to generate fewer emissions than hill and upland farms because they yield more meat per hectare and per breeding ewe.

Appropriate feed management can make the difference between generating a profit or a financial loss for every lamb sold.

Improving forage quality, especially digestibility (D-value), improves productivity and reduces emissions. The higher the D-value of forages, the less concentrates a flock needs.

As forage accounts for the bulk of the breeding, growing and finishing diets, improving quality and utilisation will improve profitability and environmental outcomes.

Grass-legume mixtures and multi-species swards, for example, can result in fewer emissions from rumination (methane) and fertiliser production (nitrous oxide). Nitrous oxide is about 300 times more potent than carbon dioxide at heating the atmosphere.

To get the most from alternative plant species you need to manage the sward quality carefully, with plenty of clover in the ley to reduce reliance on synthetic nitrogen fertiliser – one of the biggest sources of GHG emissions in agriculture.

Incorporating herbs builds resilience into the sward when grass growth comes under stress from changeable weather.

Harvesting the sward when it is young will improve forage quality, as will increasing grazing frequency and shortening the regrowth interval – these will also reduce methane emissions.

The financial benefits of better-quality silage can soon add up as well. Better quality silage reduces the need for bought-in feed and supports faster lamb growth.

Pasture management is central to improving productivity and reducing emissions.

As grass matures, the concentration of fibre in it increases, this can make the sward less digestible.

The D-value is typically at its lowest when the weather conditions are hot and/or dry. A low D-value reduces feed intake and, therefore, lamb growth.

Good grazing management and including more digestible forages in the flock’s diet have the potential to increase average daily liveweight gain (DLWG), reducing days-to-slaughter and the quantity of methane emitted over the animal’s lifetime.

Incorporating white clover into perennial ryegrass or multi-species swards reduces the need for chemical nitrogen, lowering costs and nitrous oxide emissions.

Clover also has a better organic matter D-value than grass and a lower fibre content, this encourages higher dry matter intake, which can help reduce methane production.

To effectively reduce emissions and improve flock efficiency, consider the following:

• Create a whole-farm feed plan to improve feed efficiency and optimise rations
• Work with a nutritionist or feed adviser to formulate diets that meet specific nutritional needs for breeding, growing, and finishing animals
• Analyse forage quality to assess digestibility and nutrient value — use services from members of the Forage Analytical Assurance Group (FAA). Analyse forage several times during the feeding season – the quality will change over time – to ensure your feed plan meets your flock’s requirements
• Feed high-quality, digestible forages, better digestibility mean less fermentation time in the rumen and therefore lower methane output per unit of weight gain
• Enhance pasture management by incorporating legumes
• Review supplementation and only supplement where there are shortfalls in forage availability (quantity and/or quality)
• Improve silage management, cut forage early for high D-value silage
• Increase the proportion of home-grown feeds to reduce GHG emissions
• Work with your vet to create an active flock health plan