If I was to walk onto a farm and say to the farmer if the there was some clover in with this ryegrass, milk yield per cow would be three to four litres more, he would question my sanity.

However, that is exactly what is happening on the Clonakilty clover trial farm. In one paddock there are cows grazing grass only and they are milking on average 14.6 litres per day and then in the paddock right beside them there is a herd of cows grazing grass and clover swards and they are milking 18.1 litres on average, a difference of 3.5 litres per cow. Milk solids are also better with the clover/grass mix.

So far this year, the group of cows grazing the grass and clover mixed swards will have over 34kg of milk solids more per cow delivered to the tank.

That’s worth over €170 per cow so far this year. Not alone have the clover grass paddocks produced more milk solids, but they have grown more grass – an extra 250kg of dry matter in silage is in the pit from these paddocks.

French research

Some French research suggests that the clover kick comes from a mix of increased feed value and increased dry matter intake.

The French researchers would not be at all surprised by the lift in milk yield for those cows grazing grass clover swards compared to pure grass swards.

For little or no extra cost, is clover the way to go with single grass varieties? The answer is that it’s probably too early to say just yet as these results are really only year one of a five year trial to see if clover can survive and prosper with modern grazing management.

Clover has a love/hate relationship with dairy farmers, with more farmers in the hate camp than the love one to be fair.

Is that about to change? Many in the hate camp suggest the mixed ryegrass/clover swards have less dry matter in spring, too much in autumn, clover has a tendency to disappear and there are weed control issues.

However, some farmers have a strong love relationship and wouldn’t reseed without clover. Some researchers working with clover, such as Mike Egan in Moorepark, feel there were clover variety issues before, grazing management wasn’t as good as it is now, and that it will last in swards if managed properly. So maybe it deserves another chance?

Clonakilty trial

Last year, a trial was established using 44ha of the Clonakilty Agriculture College farm. Four groups of 30 cows are grazing a mix of clover/grass sward and grass only swards. There is a mix of Holstein Friesian, Jersey cross and three-way cross cows in the trial.

At this stage, the spring-calving cows are coming up to 200 days in milk. In terms of fertility, researcher Brian McCarthy and farm manager Fergal Coughlan reckon they will have achieved nearly an 80% six-week calving rate and about 10% not in calf overall. So far, about 240kg of meal has been fed per cow and over 1.1t of silage dry matter is in the pit at a stocking rate of 2.7 cows/ha.

The cows are a mix of breeds, but average about 500kg in liveweight at a condition score close to 3. The cows on the grass swards are milking about 1.35kg of milk solids, while the cows in the grass/clover swards are milking about 1.65 kg of milk solids per day at the moment (see Figures 1 and 2).

Lack of rain reduced growth in mid to late August, but recent rain has seen growth improving.

Grazing management

Similar to normal good grazing management, the target is to graze paddocks with a cover between 1,250 and 1,500kg DM/ha.

The paddocks are cleaned out to 4cm and all treatments on this trial (with and without clover) move at the same time as much as possible so they are on similar rotation length.

A 250kg of bag nitrogen per hectare is applied to all paddocks. Some could argue this is not necessary on the clover paddocks, but rightly or wrongly this is the protocol for the moment.

When the trial was being set up in 2013, milk production results showed the mixed clover grass swards delivered between 10kg and 20kg of milk solids per cow more over the year. The 2014 results are on track to show an even bigger difference. The new swards are settling in and clover is getting more established, even in paddocks that are cut for silage.

In Clonakilty, the average clover percentage in the sward rises as the year moves on. It lifts from 25% clover in April right up to 50% clover in July and August. At 50% clover content in a paddock, to the untrained eye it’s like clover has taken over in a paddock and there is little or no grass, but the grass still survives.