Central Statistics Office (CSO) (2016) measured 137,500 farms in Ireland in 2016 with a large proportion of these farms being used for livestock production. 88% of Ireland’s gross agricultural outputs are livestock based products (CSO, 2020). Ireland’s livestock production is mainly ruminant based livestock production (beef, dairy and sheep) which is largely grass fed (O′Mara et al., 2021). Pig and poultry production also takes place in Ireland however, not to the same output and extent as cattle, dairy and sheep based production (O′Mara et al., 2021). Based off The Teagasc National Farm Survey Data, O'Brien et al. (2018) stated that on average an Irish dairy cow diet consists of 81.8% of forage (60.2% being concerned with grazed pasture, 19.8% grass silage and 1.8% alternative forages) and the other 18.2% was concentrates. Teagasc (2020) and Earle et al. (2017) report similar or higher levels of forage being used in both beef and sheep production in Ireland.
Grass-fed livestock production has numerous advantages and disadvantages. Grass-fed livestock products are usually better for consumers who buy them, with research showing that grass fed beef is lower in overall fat and saturated fat, provides more omega-3 fats, has 3-5 times more conjugated linoleic acid (CLA) and is higher in vitamin E than those of grain fed livestock (WebMD Editorial Contributors, 2020). Research from the Environmental Research and Education shows that methane emissions from livestock production are actually being offset by grazing the pasture, with GHG’s being reduced through carbon sequestration (A Greener World, 2015). Research in Queensland Australia has shown that through carbon sequestration from the grass and its soil it has offset the GHG emissions from livestock farming operations (A Greener World, 2015). Grass-fed systems are also believed to produce healthier and more fertile livestock which have a long life span therefore reducing the wastage of animals on the farm (A Greener World, 2015). If stock on the farm are better and healthier the less need there is for replacement animals to maintain productivity which in turn has a positive effect on GHG emissions (A Greener World, 2015). However there is no denying that research has shown that ruminant animals are huge cause of methane and carbon dioxide agricultural emissions worldwide (Opio et al., 2013). However, this post aims to look at how we can reduce such emissions by looking at alternative feeds for livestock and the environmental advantages they bring to the Irish livestock sector which will help Ireland meet they’re climate targets without diminishing production levels.
The Department of Primary Industries and Regional Development (2022) list 3 methane- reducing feed additives and supplements;
- Synthetic Chemicals
- Natural Supplements and Compounds
- Fats and Oils
Synthetic Chemicals
These include the use of antibiotics which have the ability to improve the efficiency of feed conversion in livestock (Department of Primary Industries and Regional Development, 2022). However the use of these chemicals are usually not recommended due to laws around the use of such chemicals and the production of livestock related products as well as concern for human health when using these chemicals in food producing animals (Department of Primary Industries and Regional Development, 2022). Such chemicals include vaccines (however a lot more research needs to be done in this area), reductive acetogenesis (McAllister and Newbold, 2008), bromochloromethane and chloroform (Tomkins et al., 2009), protozoa (McAllister and Newbold, 2008), and antibiotics such as monensin (Eckard et al., 2000).
Natural Supplements and Compounds
Bovaer10
Bovaer10 is a new food additive to the market which contains 3-nitrooxypropanol which reduces methane emissions from dairy livestock (European Commission, 2022). EFSA Panel on Additives et al. (2021) researched the food additive showing that it is effective to reduce emissions at a recommended level in feed of 60mg 3-NOP/kg DM feed. The additive is able to do this while not causing any concerns or threats for consumers who may consume dairy livestock products (EFSA Panel on Additives et al., 2021). However, research still needs to be carried out to see if the additive is affective in other ruminant animals (EFSA Panel on Additives et al., 2021). European Commission (2022) mention that this additive has the potential to cut emissions in dairy cows by between 20-35% while not affecting production of the cow.
Seaweed
Asparagopsis armata or more commonly known as seaweed have shown to be huge a contributor to the reduction of methane produced by enteric fermentation when included into livestock’s diets. Roque et al. (2021) and Roque et al. (2019) research found seaweed when included in livestock’s diet can be effective in reducing methane emissions. Roque et al. (2019) looks at the inclusion of seaweed into dairy livestock’s feed with research showing a that a 0.5% inclusion of seaweed seen a 26.4% decrease in methane production, a 20.5% decrease in methane yield and a 26.8% decrease in methane intensity. This 0.5% inclusion did not see an impact in milk yield or intake in dairy livestock. Roque et al. (2021) examined the introduction of seaweed into beef livestock diets in comparison to beef livestock diets fully resilient on forage. The study found methane emissions decreased by 33% depending on how much seaweed was consumed. The study also found that feed to body weight conversion was 20% more efficient with the introduction of seaweed into cattle’s diet than those cattle who consumed high-forage diets meaning less food needs to be produced or bought in by farmers and overall reducing production costs.
Nitrates
Nitrates are another option to reduce enteric fermentation emissions generated by livestock. Nitrates are chemicals which naturally occur in soils, plants and water which naturally combine with hydrogen rather than methanogens (Carrazco, 2021). van Zijderveld et al. (2011) research highlights that the introduction of nitrates into dairy livestock diets brought on average a 16% reduction in methane emissions caused by enteric fermentation while Lee et al. (2017) research found that the introduction of such nitrates into beef livestock’s diets brought a 12% reduction in methane emissions caused by enteric fermentation. However, one point to note is that too much nitrates included in a diet can cause nitrate poisoning in ruminant animals with cattle being the most affected by such poisoning (Thompson, 2021). Therefore the inclusion of nitrates into livestock’s diets needs to be monitored very closely to avoid this risk (Carrazco, 2021).
Fats and Oils
Typically fats have been included in livestock’s diets to increase the energy density of the diet, to increase milk yield and to alter the fatty acid composition of milk fat (Murphy et al., 1995, Ashes et al., 1997). However, recent studies has shown that the inclusion of fats into livestock diets can reduce livestock’s methane emissions (Dong et al., 1997, Machmüller and Kreuzer, 1999, Dohme-Meier et al., 2000). Research by Dohme-Meier et al. (2000) have shown that the addition of 53 g kg–1 DM of palm kernel oil reduced emissions by 34%. The same amount of coconut oil seen a 21% reduction in methane emissions and the same amount of canola oil seen a 20% reduction in methane emissions. Research also showed that a 3.5% inclusion of coconut oil in sheep diets seen a 28% decrease in methane production while a 7% inclusion of coconut oil in sheep’s diets seen a 73% decreased in methane production (Machmueller and Kreuzer, 1999). These fats and oils may not always reduce methane emissions however, it may improve productivity per unit of methane produced, for example Johnson et al. (2002) found that supplementing 4% of oilseeds into dairy livestock’s diets increased the efficiency of milk produced per unit of methane produced. Another oil which has been useful in reducing enteric fermentation emissions is Agoilin (“a commercially available blend of coriander seed oil, and extracts from common nutmeg and wild carrot”) (Carrazco, 2021).
In conclusion livestock farming produce huge amount of methane however through the introduction of such methods discussed above we could reduce methane emissions and therefore seen an overall reduction in GHG emissions in a shorter period of time with methane only having a lifespan of 10-12 years within the atmosphere (NatureFood, 2021).
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