Beef 2022 Open Day, this week, explored six ways that beef farmers can reduce greenhouse gas emissions.
Some of the “key” technologies available to beef farmers that advisors discussed at the national event included:
- Improved animal performance;
- Reduced age at slaughter;
- Protected Urea;
- Reducing chemical nitrogen use.
Reducing chemical nitrogen (N) use
In addition to switching to lower-emitting forms of fertiliser, reducing total quantities of chemical N reduces N2 O emissions, attendees heard.
According to Teagasc, reducing N fertiliser by 10 kg per ha will reduce farm GHG emissions by 1% and improve income by €10/ha.
Protected Urea is designed to slow the rate at which urea is converted to ammonium, reducing N2 O emissions.
This product has, Teagasc claims, 71% lower nitrous oxide emissions than CAN.
According to the state agency, PU is 25-30% cheaper than CAN and grows “similar” yields of grass.
Nitrous oxide (N2 O) is a GHG which has almost 300 times more global warming potential than carbon dioxide (CO2 ).
It is lost to the atmosphere from the breakdown of organic and chemical fertiliser.
The spreading of chemical fertilisers including calcium ammonium nitrate (CAN) emit high levels of N2 O.
Improved animal breeding performance
On the day, advisors discussed the importance of improving replacement indices, a younger age of first-calving and a higher calving rate.
According to the state agency, improving the replacement index of breeding females results in:
- Improved efficiency;
- A reduction in GHG emissions from non-productive animals;
- Better fertility.
Teagasc-led research work shows that 5-star animals improved profitability by €55/animal, compared to 1-star animals.
Additionally, 5-star animals, it claims, were 10% more carbon-efficient than 1-star animals.
Higher calving rate
According to Teagasc, improving the calving rate by 5% will increase the profitability of by €49 / cow or €1,960 for the herd of 40 cows.
Furthermore, improving calving rates by 5% will reduce GHG emissions by 3%.
Currently, according to ICBF data, the national average calving rate for suckler cows is 0.83 calves/cow/year.
Attendees were told that if a cow does not produce a calf every 12 months, the carbon footprint of that animal increases.
They explained that “there is less beef produced to ‘dilute’ the emissions produced, which remain largely the same per cow whether or not a calf is produced”.
Younger age at first calving
Suckler herds in Ireland, according to ICBF data, have an average age at first-calving for replacement heifers of 30.5 months.
The top 10 % of herds achieve an average figure of 26 months.
A Teagasc spokesperson said:
“Compared to a heifer calving at 24 months, older heifers at first-calving have greater total lifetime emissions.”
The higher emissions come from:
- Enteric fermentation;
- Feed energy;
- Manure management;
- Storage and spreading of slurry.
Therefore, the state agency believes there is “considerable” scope for improvement on a national scale.
The spokesperson continued:
“The economic impact of lowering the age at first-calving by one month is estimated at €10/cow.”
“The impact of age at first calving is to increase GHG emissions by 0.8% for each month that first-calving is greater than 24 months of age.”
Increasing the grazing season length lowers GHG emissions, Teagasc told crowds at Grange this week.
Grazed grass, it conveyed, has higher digestibility than grass silage resulting in improved productivity and less energy lost as methane.
Also, the ensuing shorter housing period means less slurry stored and less slurry to be applied, resulting in fewer emissions.
The state agency estimates that for every 10-day increase in days at grass, profit increased by €25 / cow or €1,000 in a 40-cow herd.
The corresponding reduction in GHG emissions is 1.7%.
Teagasc believes implementing a “comprehensive” health plan will improve the efficiency of the farming system.
It says that it will reduce GHG emissions by improving breeding performance and reducing the age at slaughter.
Reduced age at slaughter
Teagasc explained that finishing animals older at slaughter results in:
- Higher lifetime emissions from “greater” quantities of methane produced;
- Additional emissions from slurry stored and spread;
- Also, dung and urine excreted during grazing.
It estimates the economic impact of increased weight gain at €0.21 per kg of beef produced for an increase of 100g /head/day in a lifetime performance.
It estimates the impact of increased weight gain on GHG emissions at 2% per 100 g increase in lifetime average daily gain for beef cattle systems.
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