The dry conditions seen in recent weeks are similar to the weather pattern of 2018, and back then it took four weeks from the return of rain for grass growth to return to seasonal averages, AFBI scientist Dr Debbie McConnell told a CAFRE webinar on Tuesday.
Although the dry weather has come to an end, McConnell said that there was not a lot of rain in the forecast, and as a result the GrassCheck model was predicting that growth would remain low over the next two weeks.
Beyond that, the experience from 2018 is that there could be a surge in growth later in the season. In late August 2018, some of the farms in the GrassCheck programme recorded growth over 100kg dry matter per hectare (DM/ha) per day, which is growth normally confined to the peak month of May.
But by the end of July, two-thirds of growth would normally have taken place, so the capacity to make up the overall shortfall is probably limited, said McConnell.
To date in 2021, total grass yield recorded at the GrassCheck plots at AFBI Hillsborough and Greenmount is 6.7t DM/ha, which is 22% down on the long term average of 8.6t DM/ha.
Growth was slow in March and April due to cold weather, while May rainfall was recorded at 161% of the seasonal average. Growth was above average in June, but rainfall was only 52% of the average, and those dry conditions have persisted into July.
While Down and Antrim have been hardest hit by dry conditions, the impact was also starting to be seen further west, said McConnell.
However, the data from the GrassCheck farms across NI highlight considerable variation in grass growth.
Fermanagh is at the long-term NI farm average of 7.3t DM, with Derry at 7.1t, followed by Tyrone at 6.9t and Antrim and Armagh at 6.7t.
The main deficit is seen in Co Down, where on-farm grass yields have averaged only 6.1t DM/ha.
Keep feed in the diet, advises Keown
Dairy farmers who have been forced to put additional feed into the diet in response to the dry conditions should not change course for now, CAFRE senior dairy adviser Conail Keown recommends.
“It will take 10 to 14 days for grass to come back again, so continue on the path you are on. In the meantime, get nitrogen on now,” maintained Keown at the CAFRE webinar on Tuesday.
He said that dairy farms in east Co Down are hardest hit, with many having average farm covers around 1,850 to 1,900kg DM/ha, which effectively means there is no grass available to cows on the farm. These farms should wait until average farm cover gets back to around 2,000kg DM/ha before considering taking out the additional feed going in at present.
In terms of how feeding has worked in practice, Keown said that additional concentrate feed in the parlour was probably the primary mechanism used on farms given it is convenient to implement. But he warned farmers not to exceed a 50:50 ratio of forage to concentrate on a dry-matter basis as this could lead to health issues in cows.
In addition, the protein in the ration probably needs adjusted as the protein content of grass will have dropped (due to low nitrogen uptake by the plant). If silage is being fed it will naturally have a lower protein content.
To offer silage, some farmers have sacrificed a paddock near the yard and put in ring feeders. Others have used mobile feeders or a diet feeder to put out a line of silage behind strip wire while still moving cows across all the paddocks.
“Both have worked reasonably well. What maybe hasn’t worked so well is where cows are allowed to run in and out of a shed, due to slippery floors,” said Keown.
Take control of grazing
Beef and sheep farmers tend to try to ride out the storm, but need to realise that issues around the lack of grass are not going away over the next two to three weeks, senior beef and sheep adviser John Sands told farmers on Tuesday’s webinar.
“If you are short of grass, you need to take control immediately,” said Sands. He maintained that for those set-stocking, the first step should be to buy an electric fencer and wire, allowing farmers to ration whatever grass is available, while trying to build up some grass elsewhere. Buffer-feeding will have to continue for now in many situations.
On some farms there is the temptation to allow cattle and sheep into fields set aside for second- or third-cut silage, but Sands advised that this should only be done where there are already sufficient silage stocks in the yard. Instead, to reduce demand, farmers should consider selling heavy cattle, culling poor performers, or weaning the strongest calves.
Time running out for wholecrop
While many farms have reasonable stocks of silage, as long as growth remains below demand, an increasing shortfall is being created. In some areas there might be the potential to buy a crop of wheat for wholecrop, however, the window to do that is becoming very tight. “You need to be speaking up very quickly,” said CAFRE senior arable adviser Robin Bolton.