Increase Lipid Content of the Diet
System: Dairy Cattle
Applicability
Mainly applicable for: Low initial fat content of the diet (i.e. no fat-rich supplements included already), TMR systems, and zero- or low-grazing systems
Not applicable or effective for: Not applicable if in the reference situation the diet already has a 7% fat content, because extra supplementation would lead to trade-offs such as reduced DMI and fibre digestibility.
Description
Supplementing fats, oils, or free fatty acids (saturated or (poly)unsaturated) to the ration or to concentrate feed, in order to reduce the enteric methane emission in the rumen. It also delivers a high energetic source to the animal. Different types of lipid can be fed, such as coconut oil, sunflower oil, palm oil, or ingredients with a very high oil content such as crushed oilseeds. They can be applied in different forms; the so-called unprotected forms exerting an effect on rumen fermentation versus the protected forms with minimal impact and interaction with rumen fermentation. Exceeding the maximum level of usage, in particular of unprotected forms, increases dietary fat content too much and negatively impacts rumen function, fibre digestion, dry matter intake and milk production.
Mechanism of effect
Increasing the dietary lipid content reduces enteric methane emissions, mainly due to i) increased digestive efficiency, as lipids are high in energy (and low in fibres); ii) direct inhibition of methanogens, reducing their activity; iii) an effect on cell-wall degradation (to be prevented as it reduces feed efficiency), and iv) changes in the rumen fermentation profile (volatile fatty acids, and associated amount of hydrogen/methane produced) leading to less hydrogen production as substrate for methanogens. It also reduces emissions per kg product due to increased productivity. Adding lipids to a diet also leads to a lower nitrogen (N) content relative to the energy content of the diet, thereby reducing N excretion and ammonia and nitrous oxide emissions. Some lipids are associated with land use change (LUC) effects, such as palm oil or soybean oil from areas with deforestation risks.
Effects on GHG emissions
Reference situation: Normal lipid content of the diet without inclusion of a product as fat/oil supplement, enabling fat supplementation of 3-4% of dietary dry matter as fat.
Effect on total greenhouse gas (GHG) emissions (LCA)
| Mean effect and range in kg CO2-equivalents | per kg product | per farm | |||
| Mean | Min-Max | Mean | Min-Max | Level of evidence | |
| Lipid supplementation | ●● | ? – ●● | ● | ?-●● | High |
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 | |
| Lipid supplementation | ●● | ● | ● | ● | |||
*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
Lipid supplementation
All (unprotected) fats/oils can be expected to have a significant mitigating effect on methane, but the size of effect depends on the type of fat/oil supplemented, degree of saturation of fatty acids, application form (i.e. rumen-protected or unprotected), inclusion rate, and may also depend on diet type and composition, and animal characteristics. The effect can be large up to a maximum of 7% fat in dietary dry matter (which means a 2-3% supplementation to a basal diet) and the use of specific unsaturated fatty acids (UFA). The reduction is greater in rations with more concentrate feed relative to forage, possibly because of lower rumen pH, and less impact of a decline in forage fibre digestibility. Research is fully conclusive on the overall methane mitigating effect of fat/oils, however less clear about differences between fat/oil sources and fatty acids types. The use of fats or oils associated with a high risk of land use change (e.g., palm oil or soy bean oil from areas with deforestation risks) should be avoided.
Other Effects
Effects on yield and cost-effectiveness
| Yield | Labor | Costs and revenues | ||||
|---|---|---|---|---|---|---|
| Animals | Crops | Time | Capital investment | Operational Costs | Revenues | |
| Lipid supplementation | ● | 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 | |
| 3-Nitrooxypropanol (3-NOP) | Land use or occupation, Societal and cultural acceptance | – |
| Literature references | Fat supplementation |
|---|---|
| Beauchemin et al., 2022 | Invited review: Current enteric methane mitigation options |
| Nayak et al., 2015 | Management opportunities to mitigate greenhouse gas emissions from Chinese agriculture |
| Eugène et al., 2008 | Meta-analysis on the effects of lipid supplementation on methane production in lactating dairy cows |
| Almeida et al., 2021 | Meta-analysis quantifying the potential of dietary additives and rumen modifiers for methane mitigation in ruminant production systems |
| 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 |
| Yulianri Rizki Yanza et al., 2020 | The effects of dietary medium-chain fatty acids on ruminal methanogenesis and fermentation in vitro and in vivo: A meta-analysis |