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Supporting future sustainability

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Can we improve pasture-based sheep and beef production using multispecies swards? ask Tommy Boland, Alan Kelly, Bridget Lynch and Helen Sheridan, University College Dublin.

The ability to grow and utilise large quantities of good-quality grass is an important competitive advantage for Irish systems of dairy, beef and sheep production. Perennial ryegrass-based swards dominate the recommendations and research agendas in countries such as Ireland and New Zealand that are synonymous with pasture-based production systems with legumes, particularly white clover, incorporated to varying, but usually low, levels. In recent years, work carried out at University College Dublin (UCD), in conjunction with Teagasc and the Agri-Food and Biosciences Institute (AFBI) in Northern Ireland, and funded by the Department of Agriculture, Food and the Marine, clearly shows that a number of advantages in terms of animal performance and health, reduced requirements for chemical inputs and enhanced biodiversity and soil health are achieved by grazing animals on multispecies swards. The swards contain a number of grasses, legumes and herbs, with each making their own specific contribution to the performance and/or health of the sward, the animal and the environment.

Exploring multi-species swards for beef production
This work was initially conducted with sheep as the animal under investigation. Now UCD, through the School of Agriculture and Food Science, is moving the focus on to the beef industry and particularly dairy calf-to-beef systems. Approximately 25ha of land at UCD’s Lyons Farm has been set aside for a long-term grazing study to determine the impacts of grazing multispecies swards by beef cattle on a range of important variables including, but not limited, to:

  • Animal performance in terms of average daily gain (ADG), KO percentage, carcase grade and composition;
  • Animal health, with a specific focus on parasite burden;
  • Meat quality;
  • Rumen function;
  • Environmental emissions, namely methane and nitrogen;
  • Herbage yield and quality;
  • Sward botanical composition;
  • Species persistency and resistance to weed ingress; 
  • Soil fertility; 
  • Soil carbon sequestration and soil associated greenhouse gas emissions;
  • Nutrient loss in groundwater; and
  • Invertebrate biodiversity.

Measuring nutrient loss

To facilitate this, three farmlets will be established. Each farmlet will be divided into four hydrologically isolated replicates, or fields. Each field will be further subdivided into two for the purpose of grazing management. The hydrological isolation involves a very intensive process of drainage and the placement of impermeable barriers, beneath the soil surface to facilitate the total collection of ground water from each individual field, or hydrological isolate. This will allow the measurement of nutrient loss in this drainage or ground water.

A long-term study
The three farmlets will differ in terms of the sward type of grazing mix grown. These will consist of a perennial ryegrass-only pasture, a perennial ryegrass plus white clover pasture with reduced nitrogen fertilisation and a multispecies sward. The university has made a unique and long-term commitment to this programme of research, which is essential as many of the soil and environmental benefits are not captured in a three-to-four-year time horizon. The long-term nature of this study will also allow important issues such as persistency of multispecies swards and how best to rejuvenate multispecies swards to be addressed.

This unique piece of infrastructure will support multidisciplinary research involving people right across the disciplines within UCD, plus collaborations with colleagues from research institutes in Ireland and internationally to support the future sustainability of the Irish beef industry.

 

 

 

Tags: Pasture-based Sheep production Beef production Long-term grazing study