Optimize the type and amount of concentrates
System: Sheep
Applicability
Mainly applicable for: Intensive and semi-Intensive sheep production systems
Not or less applicable for: Pastoral or transhumant systems (full grazing)
Description
Changing the level and/or type of concentrates in the diet, either by increasing the dietary concentrate level at the expense of forage or by optimizing the amount and composition according to individual animal requirements (balanced rations). To avoid increases in GHG emissions, concentrate ingredients with a low carbon footprint should be used (see factsheet ‘Purchase low-emission feed ingredients’) and protein intake should be optimised. For sheep, application of concentrates is relatively less important than for dairy cattle. Optimizing concentrates, if applied with sheep production, is important and common practice and will also impact GHG emission per unit of product.
Mechanism of effect
Increasing the dietary concentrate proportion at the expense of forage reduces enteric methane emission, mainly due to shifts in the volatile fatty acids profile in the rumen. Optimizing the amount and composition of concentrates according to animal requirements can reduce GHG emission intensity (GHG per kg product) due a faster animal gain and more efficient utilization of feed resources.
Upstream GHG emissions may increase due to emissions during production and transport, and land use change associated with purchased concentrates. To avoid this, concentrate ingredients with a low carbon footprint should be used (see factsheet ‘Use feed ingredients with a low carbon footprint’). To avoid increases N2O emission due to increased dietary N intake, protein intake should be based on individual requirements (such as production potential and production stage).
While a reduction of total GHG emissions requires optimization of the dietary concentrate level, only an ‘increase dietary concentrate level’ is shown in the tables below because of insufficient papers on reducing or optimizing dietary concentrate levels.
Effects on GHG emissions
Reference situation: Average dietary level of concentrates
Effect on total greenhouse gas (GHG) emissions
| Mean effect and range in kg CO2-equivalents | per kg product | per farm | |||
| Mean | Min-Max | Mean | Min-Max | Level of evidence | |
| Increase dietary concentrate level | ● | ● – ●● | ● | ●–●● | Medium |
Legend
| ● – Small effect (<5%) | o – No effect | ? – Effect unknown |
| ●● – Medium effect (5-20%) | ● – Unfavourable effect | |
| ●●● – Large effect (>20%) | ● – ● – Variable effect (depending on farm characteristics or way/level of implementation) | |
Effect per emission source
| Mean effect on absolute emission from | Animal | Manure storage | Feed and forage production | Barn | |||
| CH4 | CH4 | N2O | CO2 | N2O | LUC | CO2 | |
| Increase dietary concentrate level | ●● | ?* | ?* | ?* | ?* | ?* | |
*risk of an adverse effect (see ’cause of variable or unfavourable effect’)
Legend
| ● – Small effect (<5%) | o – No effect | ? – Effect unknown |
| ●● – Medium effect (5-20%) | ● – Unfavourable effect | |
| ●●● – Large effect (>20%) | ● – ● – Variable effect (depending on farm characteristics or way/level of implementation) | |
Cause of variable or unfavourable effect
Increase dietary concentrate level
The effect depends on the initial feed ration composition, the type and amount of concentrates, feed intake level, initial production levels, breed, and feeding frequency. The effect also depends on the carbon footprint of the initial and new feed ration; the reduction in methane emissions due to increased productivity can be offset by a high carbon footprint related to production and processing of raw materials and effects on LUC and soil C. Nitrous oxide emissions from manure and soils can increase in case of a higher crude protein intake.
Other Effects
Effects on yield and cost-effectiveness
| Yield | Labor | Costs and revenues | ||||
|---|---|---|---|---|---|---|
| Animals | Crops | Time | Capital investment | Operational Costs | Revenues | |
| Optimize dietary concentrate level | o-●● | ●–● | ● | o-●● | ●–●● | |
Legend (thresholds differ per indictor and can be found in the tooltip)
| ● – Small favorable effect | o – No effect | ? – Effect unknown |
| ●● – Medium favorable effect | ● – Unfavourable effect | |
| ●●● – Large favorable effect | ● – ● -Variable effect (depending on farm characteristics or way/level of implementation) | |
Effects on other sustainability aspects
| Risks of trade-offs | Potential synergies | |
|---|---|---|
| Optimize dietary concentrate level | Ammonia emission, Water use |
| Literature references | Increase dietary concentrate level |
|---|---|
| Arndt et al., 2022 | Full adoption of the most effective strategies to mitigate methane emissions by ruminants can help meet the 1.5 °C target by 2030 but not 2050 |
| Batalla et al., 2014 | Integrating social and economic criteria in the carbon footprint analysis in sheep dairy farms |