meth Flashcards
what % of Irish agriculture greenhouse gases does methane make up ?
63%
what % of total greenhouse gases is as a result of greenhouse gases
37.8%
breakdown in % of irelands greenhouse gas emissions
fermentation - 63%
manure management - 11%
agri soils - 18%
liming - 2.2%
by how many Mt CO2eq will the MACC model reduced emissions by
1.5 - 2
by 2030 what is the aim for Mt of emissions due to agriculture
17.25Mt
what are 2 key challenges to reduction in emissions
- develop more technologies
- support farmers with adoption
what are the almost ready technologies available to farmers
feed additives
fertiliser
earlier slaughter
what are the early stage technologies available to farmers
feed additives at pasture
breeding low emitting animals
what is the global warming potential of enteric methane
CO2 x 28
what is methane a mechanism to remove from the animal
hydrogen
why dont kangaroos excrete methane
acetogens dominate rather than methanogens
what component of feed produces the highest amount of methane
fibre
why are the methanogens located close to the protozoa
easy transfer of hydrogen to produce methane
why does fibre diet produce more methane and starch diet
type of VFA’s produced any diet that promotes acetate production (fibre) has higher methane
why do hindgut fermenters not produce much methane
acetogens dominate and these utilise the hydrogen
how is methane excreted in hindgut fermenters
is absorbed into blood and excreted in the breath by the lungs
how many species of methanogens are their in the diet of rumen
13
why cant we add acetogens to a rumen diet to reduce methane
- difficult to change rumen microbial population
- live population of acetogens needs to be fed to animals
what feeds results have been proven to lower methane production in ruminants
- improved forage quality
- feed concentrates
- feed additives
what % of total energy consumed is lost through methane
5 - 10 %
why is methane important in terms of energy
methane is energy dense (55MJ/kg) so animal could be losing out on all this energy
why is propionate produced in high starch diet and how does it reduce methane
starch lower rumen pH hence the production of propionate and needs 4H in order to be converted from pyruvate hence utilising it
equation of end products of CHO digestion
CO2 + 4H2 = CH4 + H20
what % of total microbes is archaebacteria or pathogens
0.5 - 3 %
what type of environment do pathogens need
anaerobic environment
what is the main driver of methane production
feed intake
what is the main challenge with trying to come up with strategy to reduce methane
antigens need to get directly into rumen only way to do so is through saliva
what are the 3 feed additives proven to reduce methane
- 3 - NOP
- aspargopsis or red seaweed
- nitrate
what is the problem with testing in vitro
very little of the results shown are actually seen in vivo
what are the 3 methane reduction strategies
- propionate enhancers
- alternate hydrogen sink
- targeting rumen methanogens
what are the 2 constraints with feed additives
- insufficient evidence of a co benefit
- needs to be fed continuously in feed ration
what is the mean reduction by using bovaer
up to 30% reduction
how does bovear work
limits the last step of the methanogenesis cycle
cost of bovaer
€25.55 annually beef cattle
€60.59 annually for dairy cows
how long after feeding will the reduction in methane occur
2.5 hours post feeding
whats the overall reduction in pasture system feeding twice daily
7%
from laharts research was was the overall reduction when fed using a diet feeder in the dry period
22% reduction
reduction in methane when fed using a diet feeder in winter milk system
25% reduction
what are oxidising methane inhibitors
peroxide based compounds
inhibit methanogens and divert electrons from H2
what % reduction in methane has been seen by using oxidising methane inhibitors
reduction by 17% on low dose
reduction by 28% on high dose
what % reduction in H2 was seen using the oxidising methane inhibitors
32-36%
why is oxidising methane inhibitors easy to deliver
can be fed twice daily through a pellet
what is greenbreed
identification of low methane emitting cattle
what was the affect of sward type on carbon footprint
compared to PRG animals grazing ryegrass plus white clover or the multispecies sward had a 15% lower carbon footprint
what % methane reduction did feeding 1300kgDM compared to 2800kgDM
7% per day
22% per kg ADG
what is defaunation
removal of protozoa responsible for methane production
challenge with defaunation
finding substrate non toxic to other bacteria
achieve without compromising fibre digestion
what are methane reduction potentials of linseed oil supplementation
17% reduction per day
20% reduction/kg MS
seaweed methane reductions
98% per day
22% increase ADG
