The only effective way to reduce bulk tank SCC is to keep high SCC milk out of the tank. How can we do this? Start by identifying which cows are contributing to the problem. Ask:
Do they have clinical mastitis? (ie clots, flakes in the milk, hard/swollen quarter). Do they have subclinical mastitis? (ie no visual signs of mastitis, but SCC >200,000 cells/mL). Step 1: deal with clinical mastitis
For the cases of clinical mastitis, you can fore-strip the milk of the cows before milking to observe if there are any abnormalities. If there are, then treat the affected quarter with antibiotics as soon as possible. The milk of a cow with clinical mastitis is milk with an extremely high SCC (millions of cells/mL). If cows have repeated cases of clinical mastitis that have been treated, you may want to consult your veterinarian to change the antibiotic product, but you should also consider drying-off that quarter. Also, if a quarter seems to be going ‘dry’, plug the teatcup and do not milk that quarter to the tank, as it is more than likely a very high SCC quarter.
Step 2: track subclinical mastitis cases (SCC>200,000 cells/mL, but visual signs)
If your bulk tank SCC is creeping up but you can’t find obvious clinical cases, you’re likely dealing with subclinical infections.
Use regular milk recording to spot problem cows.If only recording four times a year, there may be a delay to identifying cows contributing to a rising bulk tank SCC, so supplement with the California Mastitis Test (CMT) to find high SCC quarters in the meantime.Treat affected quarters with antibiotics as needed. Use the ICBF Milk Recording Lifetime report to guide decisions:Cows on the persistent infected (red) list with high SCCs last lactation (especially if already treated at dry-off) have a low chance of cure. These are often infected with Staph. aureus, which is contagious. If not acted upon, these cows can worsen the problem. The best option is to dry the high quarter of these cows or to cull as soon as possible. For cows in the new infected (yellow) list, look at their contribution of SCC to the bulk tank (“% tank SCC” column). If it is high (eg >~7%), consider treating the quarters or keeping the milk out of the tank and wait to see if the SCC of the cow reduces. You can check this by doing the CMT a week or two after treating. To lower bulk tank SCC and to control mastitis problems it is very important to keep the milk of very high SCC cows out of the tank and to stop the spreading of infection from high SCC to low SCC cows. Come to the One Health-One Welfare village at Moorepark 2025 to discuss strategies to reduce SCC in your herd.
Updating enteric methane emissions factors
Enteric methane, a by-product of feed digestion, accounts for the majority of greenhouse gas emissions from the Irish dairy sector. Currently, methane emissions from Irish dairy cows are predicted using international default methane conversion factors. Research at Teagasc Moorepark has found these default values overestimate methane output by 8% in grazing dairy cows and 22% in dry cows consuming grass silage. This research has been used to generate methane conversion factors more representative of Irish dairy systems. These updated factors will allow for more accurate national methane accounting and lower the carbon footprint of Irish milk from 0.96 to 0.88 kg CO2-equivalents per unit of fat and protein corrected milk (CO2-eq/FPCM), enhancing Irish milk’s global competitiveness.
Research is also examining how grazing management and sward type influence methane emissions. Results show a strong seasonal pattern in methane output at grass, with the lowest daily emissions observed in spring. The reduced methane emissions in spring relate to highly digestible grass with low fibre content during this period. This suggests that, where conditions allow, getting cows out to grass earlier in the spring can be a strategy to reduce on-farm methane output.
Research is also evaluating the potential of feed additives to reduce methane emissions under Irish conditions; 3-Nitrooxypropanol (3-NOP) has been shown to reduce methane emissions indoors by 22% and 26% when mixed into grass silage and TMR diets, respectively; however, mixing wagons are required to achieve these reductions.
When 3-NOP was top-dressed onto grass silage indoors, methane emissions decreased by 12%. Another study found that 3-NOP, pulse-fed twice daily in concentrate feed to grazing dairy cows, reduced methane by ~30% for 2.5 hours post-consumption; however, this effect was short-lived, resulting in only a 5% reduction in daily methane emissions.
Recent research has shown that a red seaweed known as Asparagopsis can reduce methane by up to 24% when dusted on concentrates fed twice daily to grazing dairy cows. Ongoing research is developing solutions to increase the practicality and efficacy of feeding additives within pasture-based systems while also evaluating potential business models for their adoption by the dairy industry. Come to the Environmental village of Moorepark 2025 to discuss enteric methane levels and mitigation strategies.
The only effective way to reduce bulk tank SCC is to keep high SCC milk out of the tank. How can we do this? Start by identifying which cows are contributing to the problem. Ask:
Do they have clinical mastitis? (ie clots, flakes in the milk, hard/swollen quarter). Do they have subclinical mastitis? (ie no visual signs of mastitis, but SCC >200,000 cells/mL). Step 1: deal with clinical mastitis
For the cases of clinical mastitis, you can fore-strip the milk of the cows before milking to observe if there are any abnormalities. If there are, then treat the affected quarter with antibiotics as soon as possible. The milk of a cow with clinical mastitis is milk with an extremely high SCC (millions of cells/mL). If cows have repeated cases of clinical mastitis that have been treated, you may want to consult your veterinarian to change the antibiotic product, but you should also consider drying-off that quarter. Also, if a quarter seems to be going ‘dry’, plug the teatcup and do not milk that quarter to the tank, as it is more than likely a very high SCC quarter.
Step 2: track subclinical mastitis cases (SCC>200,000 cells/mL, but visual signs)
If your bulk tank SCC is creeping up but you can’t find obvious clinical cases, you’re likely dealing with subclinical infections.
Use regular milk recording to spot problem cows.If only recording four times a year, there may be a delay to identifying cows contributing to a rising bulk tank SCC, so supplement with the California Mastitis Test (CMT) to find high SCC quarters in the meantime.Treat affected quarters with antibiotics as needed. Use the ICBF Milk Recording Lifetime report to guide decisions:Cows on the persistent infected (red) list with high SCCs last lactation (especially if already treated at dry-off) have a low chance of cure. These are often infected with Staph. aureus, which is contagious. If not acted upon, these cows can worsen the problem. The best option is to dry the high quarter of these cows or to cull as soon as possible. For cows in the new infected (yellow) list, look at their contribution of SCC to the bulk tank (“% tank SCC” column). If it is high (eg >~7%), consider treating the quarters or keeping the milk out of the tank and wait to see if the SCC of the cow reduces. You can check this by doing the CMT a week or two after treating. To lower bulk tank SCC and to control mastitis problems it is very important to keep the milk of very high SCC cows out of the tank and to stop the spreading of infection from high SCC to low SCC cows. Come to the One Health-One Welfare village at Moorepark 2025 to discuss strategies to reduce SCC in your herd.
Updating enteric methane emissions factors
Enteric methane, a by-product of feed digestion, accounts for the majority of greenhouse gas emissions from the Irish dairy sector. Currently, methane emissions from Irish dairy cows are predicted using international default methane conversion factors. Research at Teagasc Moorepark has found these default values overestimate methane output by 8% in grazing dairy cows and 22% in dry cows consuming grass silage. This research has been used to generate methane conversion factors more representative of Irish dairy systems. These updated factors will allow for more accurate national methane accounting and lower the carbon footprint of Irish milk from 0.96 to 0.88 kg CO2-equivalents per unit of fat and protein corrected milk (CO2-eq/FPCM), enhancing Irish milk’s global competitiveness.
Research is also examining how grazing management and sward type influence methane emissions. Results show a strong seasonal pattern in methane output at grass, with the lowest daily emissions observed in spring. The reduced methane emissions in spring relate to highly digestible grass with low fibre content during this period. This suggests that, where conditions allow, getting cows out to grass earlier in the spring can be a strategy to reduce on-farm methane output.
Research is also evaluating the potential of feed additives to reduce methane emissions under Irish conditions; 3-Nitrooxypropanol (3-NOP) has been shown to reduce methane emissions indoors by 22% and 26% when mixed into grass silage and TMR diets, respectively; however, mixing wagons are required to achieve these reductions.
When 3-NOP was top-dressed onto grass silage indoors, methane emissions decreased by 12%. Another study found that 3-NOP, pulse-fed twice daily in concentrate feed to grazing dairy cows, reduced methane by ~30% for 2.5 hours post-consumption; however, this effect was short-lived, resulting in only a 5% reduction in daily methane emissions.
Recent research has shown that a red seaweed known as Asparagopsis can reduce methane by up to 24% when dusted on concentrates fed twice daily to grazing dairy cows. Ongoing research is developing solutions to increase the practicality and efficacy of feeding additives within pasture-based systems while also evaluating potential business models for their adoption by the dairy industry. Come to the Environmental village of Moorepark 2025 to discuss enteric methane levels and mitigation strategies.
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