Optimize the type and amount of concentrates
System: Dairy 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 (e.g., lactation stage and production level; ‘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’).
Balancing rations according to individual animal requirements is not included as a measure in this factsheet because of a lack of papers from European countries. However, this acitivity is important and common practice (e.g. concentrate allowance of cows being dependent on stage of lactation), and also impacts total GHG emission per unit of product.
Mechanism of effect
Increasing the dietary concentrate proportion at the expense of forage and increasing feed intake reduces enteric methane emission, mainly due to shifts in the volatile fatty acids profile in the rumen, and increased bypass of digestible nutriens to the intestine. Optimizing the amount and composition of concentrates according to animal requirements can reduce GHG emission intensity (GHG per kg product) due to a higher animal productivity 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 in 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. Some studies showed an increase in methane emission from manure due to higher concentrate levels in the diet. The effect also depends on the carbon footprint of the initial and new feed ration; a reduction in methane emission 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 | ●–● | ●●-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, Land use or occupation | Ammonia emission, Land use or occupation, Animal welfare |
| Literature references | Increase dietary concentrate level |
|---|---|
| Borsting et al., 2023 | Replacing silage with large amounts of concentrate and straw affects milk production, economics and climate differently in Holstein and Jersey Cows |
| Agle et al., 2010 | Effect of dietary concentrate on rumen fermentation, digestibility, and nitrogen losses in dairy cows |
| Aguerre et al., 2011 | Effect of forage-to-concentrate ratio in dairy cow diets on emission of methane, carbon dioxide, and ammonia, lactation performance, and manure excretion |
| Razzaghi et al., 2022 | Energy utilization and milk fat responses to rapeseed oil when fed to lactating dairy cows receiving different dietary forage to concentrate ratio |
| 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 |
| Zumwald et al., 2018 | Life cycle assessment of grassland-based dairy production systems in Switzerland |
| De Vries et al., 2020 | Effects of feeding and manure management interventions on technical and environmental performance of Indonesian dairy farms: Results of a pilot study in Lembang Sub-District, West Java |
| Oenema and Oenema, 2022 | Unraveling feed and nutrient use efficiencies in grassland-based dairy farms |
| Berton et al., 2023 | Consequential-based life cycle assessment of reducing the concentrates supply level in the diet fed to lactating cows in the alpine dairy farming system |