Optimize the type and amount of concentrates
System: Beef Cattle
Applicability
Mainly applicable for: Intensive and semi-intensive systems, sub-optimal feed ration composition
Not or less applicable for: Full grazing, low-concentrate feeding systems
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, preferably concentrate ingredients with a low carbon footprint should be used (see factsheet ‘Use feed ingredients with a low carbon footprint’) and protein intake should be optimised (see factsheet ‘Optimize crude protein content of the diet’). However, this acitivity is important and common practice (optimizing concentrate allowance of beef cattle with roughage feeding and preserving rumen health and functionaility), and also impacts total 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 and a different functionality of the rumen with high-energy diets in particular (e.g. feedlot feeding). Optimizing the amount and composition of concentrates according to animal requirements can reduce GHG emission intensity (GHG per kg product) due a higher animal productivity and more efficient utilization of feed resources.
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. 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, type of animal, 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.
| 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 |