GrowthWatch: Keeping a close eye on pre-grazing covers

By Teagasc’s Seán Cummins and James Fitzgerald

Mid-season weighing has been completed on the majority of the Teagasc Green Acres Calf to Beef Programme farms.

Performance on an average daily gain basis has been largely on target, hovering around 1kg/day since turnout for second season animals.

However, there’s no room for complacency in terms of grassland management from here on into housing; a huge amount of ‘cheap’ liveweight is still to be achieved before the grazing season ends.

If the desired levels of liveweight gain are achieved between now and housing, it puts the participating farmers in a strong position to finish cattle as efficiently as possible over the winter months.

This excludes the need for additional concentrates or a longer-finishing period to make up for any lost kilograms of liveweight over the grazing season.

Once the health box is ticked, the most immediate task is ensuring that cattle enter the ideal pre-grazing covers from here on in, with pre-grazing covers of 1,300-1,600kg DM/ha (8-10cm) being optimal.

Where too heavy of pre-grazing covers are entered, cattle may be asked to work excessively hard to achieve the desired graze outs; animal performance may drop as a result of a higher than desired leaf-to-stem ratio.

The prospect of reduced utilisation may also be faced, with mechanical intervention to correct poorly-grazed paddocks required in some instances.

Where the average farm cover is high and growth exceeds demand, there are a number of strategies which farmers can take.

Firstly, they can identify any surplus quickly and remove them as bales. Some of the ground may also be closed for a light cut of silage over the coming weeks and taken out before farm cover begins to build in the autumn.

This is particularly the case when animals have been slaughtered off grass over recent weeks and second-cut silage ground begins to re-enter the grazing rotation.

grass growth utilisation

This method will act to increase the demand on a per hectare basis in line with growth rates and, thus, potentially make hitting the targeted pre-grazing covers slightly easier in some cases.

Depending on how paddocks have performed throughout the year, there may also be an opportunity to carry out some reseeding at farm level.

This will also serve to increase the demand for a couple of weeks until this ground is once again ready to graze. However, this method may not be required on all farms and should only be contemplated where this is, or will be, a need to grow more grass going forward.

Peter O’Hanrahan, Thomastown, Co. Kilkenny:
  • Growth: 37kg DM/ha/day;
  • Demand: 49kg DM/ha/day;
  • Average farm cover: 1,053kg DM/ha/day;
  • Stocking rate: 4.07LU/ha.

Growth has been low over the last week at a rate of 37kg DM/ha, while demand is running at 49kg DM/ha.

I’m not worried at this stage as the farm cover is high at 1,053kg DM/ha and we’re planning on blanket spreading 15 units of nitrogen (N) across the majority of the farm over the coming weeks.

Any of the ‘hungrier’ silage fields will also receive 2,000-2,500 gallons/ac of slurry over the coming weeks, to help build phosphorus (P) and potassium (K) indexes. 

We reseeded 14ac 30 days ago and that’s within about one week of coming into grazing after receiving its post-emergence spray of Pastor Trio earlier this week.

We had planned on reseeding this ground after first-cut silage on May 16, but the weather didn’t oblige and we waited until sufficient quantities of rain arrived.

We opted to stitch in the grass seed and it has worked very well, with little soil disturbance allowing us to get back in quickly after sowing.

Once we start grazing this ground, we plan on taking out additional surplus bales and hope to gather another 80 to create a buffer going forward.

We also plan on reseeding another 14ac towards the middle of August with ‘Sweetbite’ – a mixture of Abergain, Astonenergy, Aberchoice and Drumbo.

We made the decision to reduce farm cover slightly last week and 28 surplus bales were collected and added to the winter feed reserve.

There are 28-30 month steers being slaughtered fortnightly at this stage, so demand will come down further over the coming weeks.

Michael Culhane, Killaloe, Co. Clare:
  • Growth: 41kg DM/ha/day;
  • Demand: 23kg DM/ha/day;
  • Average farm cover: 741kg DM/ha/day;
  • Stocking rate: 1.98LU/ha.

Grass growth is comfortably ahead of demand over the last couple of weeks, resulting in the aged cattle and calves grazing higher grass than what I would like.

The Belgian Blue-cross calves are grazing reseeds on an out-farm with covers of circa 2,000kg DM/ha. The younger calves at home are still receiving meal and grazing covers of circa 1,600kg DM/ha, with the older cattle grazing similar grass.

To correct this, I will be cutting and baling what has gone ahead of the calves on the out-farm and then looking at adding some extra stock to the block to match growth and demand.

At home, the second-cut silage is ready for cutting and will be harvested once the weather allows. This is giving me a good opportunity to cut some of the extra grass that has gotten ahead of the stock here and put it into the pit along with the second cut.

The extra silage will all be needed in time as stock numbers are to gradually rise over the next couple of years.

I am planning to spread lime on the entire home block once the second cut is in and so the more bare ground I have to spread on the better.