Research published in 2010, which identified an autumn calving system with 8,000l cows as being the most robust and profitable option in NI, is still equally relevant 15 years later, a lead scientist at the Agri-Food and Biosciences Institute (AFBI) has said.

“A medium input system is still the most resilient over the longer term,” suggested AFBI Director, Professor Elizabeth Magowan.

Briefing agricultural journalists, she said that when a significant proportion of the 8,000l comes from grass and forages, rather than concentrate feed, the farm will have less of an issue meeting any future phosphorus (P) limits. On a well-run medium-input farm, P surplus could be between 4.5 and 6kg/ha, which is in line with long term targets set by DAERA in NI.

However, the reality is that many NI herds have now pushed well beyond 10,000l and similar yields are also being achieved in research work at AFBI Hillsborough. A potential challenge for the scientists there could be to see if it is possible for cows to produce over 10,000l, but with a P balance of under 6kg/ha. “We would need to get a lot of grass and forage into the animals,” responded Prof Magowan.

Feed

One thing that is not possible would be to reduce P in concentrate feed.

“We have done a lot of work on P in animal diets. They are probably as low as they can practically go. In theory, dairy could maybe go a bit lower but a whole other level of precision management would be required on farms to achieve that,” she said.

The other solution for P involves technology, with research at AFBI showing that mechanical separation of slurry using a decanter centrifuge can remove over 80% of P, compared to a traditional screw press separator which typically removes just over 20%. The main issue with the decanter centrifuge is the much higher cost, said Prof Magowan.

Agriculture will have a greater share of emissions

Despite greenhouse gas (GHG) emissions from agriculture in NI being down in the last three years, other sectors are able to decarbonise quicker, leaving the proportion attributed to farming now at over 30%.

According to AFBI director, Professor Elizabeth Magowan, farming must continue to make progress in reducing GHG, but also be ready to explain why our share of total emissions is going up.

By 2050, the UK Climate Change Committee (CCC) predicts that farming will account for around 75% of emissions in NI, with most of that coming from methane released by ruminant animals.

That has led some to argue that the industry should cut livestock and instead plant more crops. However, research suggests there is limited scope to expand the crop area in NI.

“There is a bit of an opportunity there, but not very much. This is still a great grass-growing region and it is still a major focus for us,” said Prof Magowan.

Dairy

Looking ahead, Professor Steven Morrison from AFBI is leading a major UK-wide project investigating potential actions and tools which could be used to drive down GHG emissions on dairy farms.

The UK dairy carbon network is a three-year project involving 56 dairy farms, 20 of which are in NI. Contracts between the farmers and the project partners are currently being signed, with formal work due to begin later this year.

In practice, a lot of hope was being put on methane-reducing feed additives such as Bovaer as being a key tool to drive down GHG emissions on farms.

However, a backlash from consumers late last year after Arla confirmed it was trialling the use of Bovaer on some supplier farms has left the dairy industry cautious.

The AFBI scientists remain “hopeful” that they might still be able to evaluate feed additives such as Bovaer in NI, but ultimately, a dairy processor would also have to buy into that.

Beef

AFBI is also the lead partner in a new project known as Clibeef, which has received over €5.7m of PEACEPLUS funding towards developing feeding strategies for beef cattle which reduce GHG emissions. Six farms in NI and six in the border counties of the Republic of Ireland will be sought for the project.

Acids can lock up ammonia in slurry

Ongoing research at AFBI shows that reducing the pH of slurry by adding acid is an effective tool that can be used to limit problem ammonia and methane emissions when slurry is stored and spread, confirmed Professor Elizabeth Magowan.

“There is not a massive adjustment required in pH to lock in ammonia and methane. But people are nervous because of the possible impact on soil health,” she said.

As a result, more research is required on the potential long term effects on the soil of spreading pH adjusted slurry. The work at AFBI is also looking at the effectiveness of other slurry additives and treatments.

Bluetongue risk is high this summer

There is a “significant chance” bluetongue will be found in NI later this summer, AFBI Entomologist, Dr Archie Murchie told agricultural reporters last Thursday.

The disease is spread by biting midges and with peak midge populations in late summer and autumn, the risk of the insects being blown over from Britain to NI is highest then.

“So far we have been lucky and managed to keep it out. It is a nasty disease that will cause us a lot of problems if it comes in,” said Murchie.

He said it is possible to catch and test midges for bluetongue, but in reality, expert advice is that you will see symptoms of the virus in livestock, especially sheep, before any positive test would come through in insects.