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Ag Sci animal N > meth > Flashcards

meth Flashcards

1
Q

what % of Irish agriculture greenhouse gases does methane make up ?

A

63%

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2
Q

what % of total greenhouse gases is as a result of greenhouse gases

A

37.8%

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3
Q

breakdown in % of irelands greenhouse gas emissions

A

fermentation - 63%
manure management - 11%
agri soils - 18%
liming - 2.2%

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4
Q

by how many Mt CO2eq will the MACC model reduced emissions by

A

1.5 - 2

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5
Q

by 2030 what is the aim for Mt of emissions due to agriculture

A

17.25Mt

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6
Q

what are 2 key challenges to reduction in emissions

A
  1. develop more technologies
  2. support farmers with adoption
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7
Q

what are the almost ready technologies available to farmers

A

feed additives
fertiliser
earlier slaughter

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8
Q

what are the early stage technologies available to farmers

A

feed additives at pasture
breeding low emitting animals

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9
Q

what is the global warming potential of enteric methane

A

CO2 x 28

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10
Q

what is methane a mechanism to remove from the animal

A

hydrogen

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11
Q

why dont kangaroos excrete methane

A

acetogens dominate rather than methanogens

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12
Q

what component of feed produces the highest amount of methane

A

fibre

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13
Q

why are the methanogens located close to the protozoa

A

easy transfer of hydrogen to produce methane

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14
Q

why does fibre diet produce more methane and starch diet

A

type of VFA’s produced any diet that promotes acetate production (fibre) has higher methane

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15
Q

why do hindgut fermenters not produce much methane

A

acetogens dominate and these utilise the hydrogen

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16
Q

how is methane excreted in hindgut fermenters

A

is absorbed into blood and excreted in the breath by the lungs

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17
Q

how many species of methanogens are their in the diet of rumen

A

13

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18
Q

why cant we add acetogens to a rumen diet to reduce methane

A
  1. difficult to change rumen microbial population
  2. live population of acetogens needs to be fed to animals
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19
Q

what feeds results have been proven to lower methane production in ruminants

A
  1. improved forage quality
  2. feed concentrates
  3. feed additives
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20
Q

what % of total energy consumed is lost through methane

A

5 - 10 %

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21
Q

why is methane important in terms of energy

A

methane is energy dense (55MJ/kg) so animal could be losing out on all this energy

22
Q

why is propionate produced in high starch diet and how does it reduce methane

A

starch lower rumen pH hence the production of propionate and needs 4H in order to be converted from pyruvate hence utilising it

23
Q

equation of end products of CHO digestion

A

CO2 + 4H2 = CH4 + H20

24
Q

what % of total microbes is archaebacteria or pathogens

A

0.5 - 3 %

25
Q

what type of environment do pathogens need

A

anaerobic environment

26
Q

what is the main driver of methane production

A

feed intake

27
Q

what is the main challenge with trying to come up with strategy to reduce methane

A

antigens need to get directly into rumen only way to do so is through saliva

28
Q

what are the 3 feed additives proven to reduce methane

A
  1. 3 - NOP
  2. aspargopsis or red seaweed
  3. nitrate
29
Q

what is the problem with testing in vitro

A

very little of the results shown are actually seen in vivo

30
Q

what are the 3 methane reduction strategies

A
  1. propionate enhancers
  2. alternate hydrogen sink
  3. targeting rumen methanogens
31
Q

what are the 2 constraints with feed additives

A
  1. insufficient evidence of a co benefit
  2. needs to be fed continuously in feed ration
32
Q

what is the mean reduction by using bovaer

A

up to 30% reduction

33
Q

how does bovear work

A

limits the last step of the methanogenesis cycle

34
Q

cost of bovaer

A

€25.55 annually beef cattle
€60.59 annually for dairy cows

35
Q

how long after feeding will the reduction in methane occur

A

2.5 hours post feeding

36
Q

whats the overall reduction in pasture system feeding twice daily

A

7%

37
Q

from laharts research was was the overall reduction when fed using a diet feeder in the dry period

A

22% reduction

38
Q

reduction in methane when fed using a diet feeder in winter milk system

A

25% reduction

39
Q

what are oxidising methane inhibitors

A

peroxide based compounds
inhibit methanogens and divert electrons from H2

40
Q

what % reduction in methane has been seen by using oxidising methane inhibitors

A

reduction by 17% on low dose
reduction by 28% on high dose

41
Q

what % reduction in H2 was seen using the oxidising methane inhibitors

A

32-36%

42
Q

why is oxidising methane inhibitors easy to deliver

A

can be fed twice daily through a pellet

43
Q

what is greenbreed

A

identification of low methane emitting cattle

44
Q

what was the affect of sward type on carbon footprint

A

compared to PRG animals grazing ryegrass plus white clover or the multispecies sward had a 15% lower carbon footprint

45
Q

what % methane reduction did feeding 1300kgDM compared to 2800kgDM

A

7% per day
22% per kg ADG

46
Q

what is defaunation

A

removal of protozoa responsible for methane production

47
Q

challenge with defaunation

A

finding substrate non toxic to other bacteria
achieve without compromising fibre digestion

47
Q

what are methane reduction potentials of linseed oil supplementation

A

17% reduction per day
20% reduction/kg MS

48
Q

seaweed methane reductions

A

98% per day
22% increase ADG

49
Q
A

Ag Sci animal N (16 decks)

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