Multi-species swards and slaughter age reduction
Recent studies at Grange have found increases in annual herbage yield of up to 25% for multi-species swards compared to perennial ryegrass swards, especially so at lower fertiliser nitrogen inputs. Researchers Edward O’Riordan, Sarah Burke, Paul Crosson & Mark McGee give some information
Irish agriculture, including beef farming, has obligations under EU and national legislation to reduce greenhouse gas (GHG) emissions and losses of nitrogen (N) and other nutrients to the environment. The recent increase in farm input prices, especially fertiliser and feed costs, brings additional challenges. Consequently, low-cost efficient grassbased beef production is now more important than ever.
Clover
For many decades, perennial ryegrass has been the dominant, sometimes the only, constituent included in grass seed mixtures used to renew grassland. More recently, white clover is included. Compared to ‘grass’-based swards, Grange research has shown the capacity of white clover inclusion to fix atmospheric N, resulting in annual savings of chemical fertiliser, equivalent to 100-150kg N/ha, for beef cattle grazing systems.
Multi-species swards
There is now increasing interest in using ‘multi-species’ swards, which include:
- grasses - perennial ryegrass and other grasses
- legumes - white and red clover
- herbs/forbs - e.g chicory and plantain
to further exploit complementarity between pasture species.
Recent studies at Grange have found increases in annual herbage yield of up to 25% for multi-species swards compared to perennial ryegrass swards, especially so at lower fertiliser nitrogen inputs. Multi-species swards may represent an opportunity to enhance the sustainability of beef production through:
- more consistent pasture supply
- increased nutritive value
- anthelminthic properties
- benefits in N-excretion
- better animal performance.
When allied to lower fertiliser nitrogen inputs, the associated environmental footprint is potentially reduced; however, these characteristics need to be quantified for Irish production systems.
Meeting live weight gain targets
A source of inefficiency in beef cattle production systems is the failure to meet live weight targets throughout the animals’ lifetime, resulting in animals being older at slaughter. Consequently, lifetime production costs, which are mainly feed-related, and the associated environmental emissions, particularly methane and nitrogen, are increased.
Nationally, mean age at slaughter for late-maturing suckler-bred steers, the predominant breed type from the suckler herd, is 28-months. This is five months later than achieved in grass-based research systems and high-performing commercial farms. Within beef production systems, older animals at slaughter are generally less profitable and have a substantially higher environmental footprint.
A challenge with younger slaughter ages on lower-cost grass-based systems is achieving adequate carcass fatness, which is currently a key market requirement. Attaining this fatness is especially demanding with late-maturing genotypes. Thus, identifying late-maturing genotypes with greater genetic propensity for subcutaneous fat deposition leading to younger slaughter ages may be a strategy to circumvent this problem.
The research
Taking these emerging demands, the objective of this research project is to assess the impact of pasture-type (grass-clover versus ‘multi-species’ grazing swards and silage), genetic divergence for fatness in late-maturing breeds, and slaughter age (19, 24 and 28 months), on the biological, financial and environmental performance of suckler weanling-to-beef production systems.
BEEF2022 Open Day
Come along to Beef2022 where you will meet Teagasc research, advisory and education staff in person.
BEEF2022 on Tuesday 5th July in Teagasc Grange is a free event and is a day not to be missed!
Further information www.teagasc.ie/beef2022
This article was first published in Today's Farm - May/June 2022 where you can read more articles like this one.