Increasing productivity and reducing methane emissions by supplementing feed with dietary lipids
The Increasing productivity and reducing methane emissions by supplementing feed with dietary lipids project investigated the impact of lipid containing feed additives on the suppression of methane emissions and improvements in the growth rate of steers fed a basal diet of tropical pastures.
Methane (CH4) is a by-product in the digestion of plant material by all cattle and sheep. As such, methane is wasted energy that could otherwise be available for animal production. It is also a major greenhouse gas (14% of Australia’s emissions) of which, beef cattle contribute 50%.
Many lipid containing feed materials are known to reduce methane emissions while increasing productivity when used as supplementary feeds.
This project investigated the impact of lipid containing feed additives on the suppression of methane emissions while improving growth rates of steers grazing tropical pastures.
Supplements were tested in vitro:
- Algamac 3050 (3, 5 and 7% oil inclusion in the diet)
- Spirulina (3%)
- canola oil (5 and 7% inclusion)
- safflower oil (3, 5 and 7% oil inclusion in the diet).
Algamac 3050 reduced methane generation at all levels of inclusion in the diet.
The inclusion of Algamac in the diet did not impact microbe population dynamics. Nor were there differences in dry-matter digestion or the numbers of methanogens or methanogen population structure.
All levels of Algamac inclusion had similar effects on the rumen microbial population and methane reduction. This observations suggests that the mechanism that lowers methane with algal oils is different to that of other oils, which directly impact the microbial ecosystem at higher levels of inclusion.
Canola oil at 7% inclusion appears to only transiently reduce methane generation. This finding causes researchers to believe canola oil would not be a good candidate as a feed supplement for lowering methane emissions.
The effectiveness of safflower inclusion is dose related. Methane production was significantly reduced, and maintained a constant level of production, when safflower was included at 7%. Whereas, at 5% inclusion, there was little effect.
Lipid containing supplements were tested in vivo in a feeding trial using Bos indicus cross steers. The supplements included Algamac, sunflower oil (due to the commercial unavailability of safflower oil) and whole cotton seed. All lipid supplements were included at a rate of 50g lipid/kg dry matter.
Supplementation increased live-weight gain over an 11 week period. Whole cottonseed supplementation (15.7 kg) provided the greatest liveweight gain, followed by Algamac supplementation (12.1 kg).
Supplementation of Algamac and sunflower oil reduced methane emissions by around 22% and 19.4% respectively.
Using these functions there was no reduction in methane emissions per head with whole cottonseed supplementation, however, when calculating methane emissions as a function of average daily gain (ADG), both whole cottonseed and Algamac supplementation had a four-fold reduction in emissions.
Taking this reduction into account, plus the increase in liveweight gain reduces the days to market, the overall reduction in methane emitted would be substantial.
The use of whole cottonseed and Algamac as a supplement to cattle grazing tropical pastures has positive impacts on live-weight gain, and reduction in methane produced per kilogram of average daily gain. However, there are supplement uptake issues that need to be overcome.
As a supplement for cattle grazing tropical pastures, whole cotton seed and Algamac, can both reduce the amount of methane producer per kilogram of daily gain in addition to having a positive impact on live-weight gain. However, there are supplement uptake issues that need to be overcome.
Date concluded: 1 December 2011
Contact: Dr Diane Ouwerkerk, Department of Agriculture and Fisheries
For more information, please read the final report summary and download the final report (B.CCH.1014) (PDF, 726 kB) from the Meat & Livestock Australia website.