Many dairy farmers are currently operating 36-hour paddocks. There are benefits from a labour point of view, it makes life easier for first calvers and there may be a potential gain in milk output.
Brendan Ryan is among the farmers using the system. Farm manager of the 400-cow dairy herd owned by the Salesian Agricultural College in Pallaskenry, Co Limerick, Brendan operates a 12-hour wire for the most of the first rotation.
But once ground conditions permit, he will move to a 36-hour paddock system, even if still in the last few days of first rotation.
He estimates that the benefit could be worth as much as 150 litres per cow across the lactation and a gain of 0.1pc of a lift in protein percentage.
However, this year Brendan has had to slightly adjust his system as construction work on the 50-point rotary parlour at the college is at a standstill because of the Covid-19 restrictions.
The 400 cows have been split into two mobs and are milked at alternate times. While the herd is split, Brendan is operating a 24-hour paddock system, but he will revert back to the 36-hour system when the rotary parlour is up and running.
Another fan of the longer residency time in paddocks is the 2018 Young Grassland Farmer of the Year Niall Moloney, who is milking 170 cows in Crecora, Co Limerick with his father Gerry.
Once the first rotation is finished, Niall moves straight away onto a 24- or 36-hour paddock system.
As there are a lot of hedgerows on the farm, the natural paddock size sometimes limits the residency time in the paddock to 24 hours.
Like Brendan, Niall estimates there is a jump in milk output by extending the length of time cows spend in a paddock.
However, he is keen to point out that it is extremely difficult to put an accurate figure on that rise, because it happens at a time when the cows’ daily output is increasing anyway.
He thinks it could be contributing one litre extra per cow, along with a 0.05pc gain in protein percentage.
He emphasises that this rise in output will not happen “unless the grass in front of the cow is right”.
Niall feels the real benefit of the extended residency time is with first calvers: “First calvers need up to three to four hours to get a full feed, whereas mature cows can eat their full allowance in two and a half to three hours,” he says.
“If you are continually on a 12-hour wire, then that first calver is spending an hour every day picking at roots and not being fed adequately.
“Moving to a 24 or 36-hour paddock system gives all the cows the same chance to eat, which is especially important for first calvers as they are not finished growing yet.”
But once again, he emphasises the importance of having the grass quality right.
Neither Niall nor Brendan have any issues with cows cleaning out the paddocks in the third grazing.
Paddock sizes in Ireland vary greatly from farm to farm, with our abundance of hedgerows and stonewalls determining our field sizes for us. Where possible, we should aim to set up our permanent wire fences to cater for a 36-hour paddock system.
Working out what size your paddocks should be can take some maths.
If we take a 100-cow herd looking to set up a 36-hour paddock system, the way to calculate the paddock size is as follows:
n Establish the grass required by the cows. 100 cows eating 18kg of dry matter per day and spending 1.5 days (36 hours) in the paddock will eat 2,700kg of dry matter (100 x 18 x 1.5).
n Then calculate what is the target grazing cover minus the residual — 1,400 – 100 = 1,300
n Divide the grass required by the pre-grazing yield to give you the appropriate paddock size. 2,700/1,300 = 2.07/ha.
In the example above a 2ha paddock would be ideal for this farmer.
However, making every paddock on the farm this size is probably unrealistic.
In this case, a 24-hour paddock would need to be 1.4ha, so it may be possible for this farmer to set up half the farm as 36-hour paddocks and the other half as 24-hour paddocks.
It may not be possible for all farmers to operate a 36-hour system all the time, but flexibility to alternate between a 24- and 36-hour paddock system should be possible for many.
And there are proven rewards for those who are willing to try it.
Joe Kelleher is a Teagasc advisor based in Newcastle West, Co Limerick