Grass+Dairy: lengthen your rotation to hold grass covers

The showers of rain that fell towards the end of last week had a good impact on parts of the north and northwest. However, the amount of rain that fell in parts of the east of the country was minimal. Growth did take a small bounce in most areas but it looks like this is going to be shortlived and with no significant rain forecast for the next week it’s important to take action and try to hold grass covers.

For those measuring grass, demand has to be lowered to match growth. For those not familiar with the figures but who can see a shortage in grass arising, set your rotation length to 25 days. So for a 100ac grazing platform you should only allocate and graze 4ac/day and then supplement to make up any shortfall.

Fertiliser should continue unless the farm hasn’t received rain in 25 days. The four things that affect grass growth are ground temperature, moisture, light and fertiliser. At the moment moisture is limiting grass growth. When rain comes you want to be able to take full advantage and don’t want the fact that there is no fertiliser available to be the limiting factor.

Correcting grass quality

Where quality needs to be corrected in a field, when a surplus of grass arises target cutting that poorer quality grass for bales.

Where this is not an option and grass is in good supply then topping or pre-mowing may be an option but only on a small percentage of the grazing block in each rotation as it will set back regrowths.

Johnstown Castle, Co Wexford

Grass is going well to date. However, the moisture deficit has gone over 45mm for the first time this week which will hit growth. We pre-mowed and grazed a few paddocks that we would normally have taken out, which has also helped the grass situation. Silage was cut here on 15 May so that ground will be available to come back into the rotation to lower the demand if the dry weather persists. The herd here is 230 days in milk, we have fed 1.3t/cow of meal and cows have produced 480kg/MS to date. Our plan is to milk on till the end of July and hope to reach 580kg/MS and keep the meal under 1.5T/cow.

Kilcormac, Co Offaly

Growth has slowed over the last few weeks. The weekend rain was needed but wasn’t long drying up. Our plan here is to keep the rotation length at 25 days. The cows are grazing a slightly stronger cover of 1,700kg/ha but what’s to follow is below 1,500kg/ha so we will increase the concentrates to hold the rotation length until more rain comes. We reseeded ground last week here. We originally were going to stitch in the grass but with the dry weather we decided to disc the field a few times and then gave it a run of a power harrow. We then sowed it before the rain at the weekend.

Teagasc Ballyhaise, Co Cavan

Things are going well here. We have skipped a paddock that is gone over the 1,500kg/ha but have decided to hold off cutting it until rain is forecast as we do expect growth to drop over the next week. We are on day 22 of the breeding season and have 91% bred. The 11 cows that are not bred were scanned and the majority were given a shot of PG to bring them in heat. One cow had a cyst and will be put on a programme and two late calves need more time. The heifers were fixed-time AI to sexed semen. So far only four repeated out of 21, now there may be more in the next day or so.