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Eamon & Donnchadh McCarthy May/June Update 2023

Silage plans

Silage plans

  • Replenishing fodder stocks for next winter
  • Quality vs. quantity
  • Planning silage cutting dates
Latest performance

Latest performance

  • First of the under 16 month bulls slaughtered
  • Remaining bulls weighed
  • Autumn bulls and heifers also weighed
Measuring grass regularly

Measuring grass regularly

  • Walking farm weekly to monitor growth
  • Paddocks taken out for silage
  • Fertiliser applications


The spring herd were housed longer than normal this year due to a slow and wet spring, and naturally Eamon and Donnchadh are concerned with how they will build back up a silage reserve for next winter. There are only 7 bales of silage left over from this winter so it is important for them to put a plan in place.

Firstly, they completed a fodder budget for the farm which indicates that they need to make at least 550 bales of silage for a 160 day winter.

Secondly they applied sufficient slurry and fertiliser to their silage fields, taking account of the soil fertility and expected crop offtakes. They used slurry analysis results to ensure sufficient phosphorous and potassium were applied to maximise yields, and 2 bags of 13-6-20 per acre were applied as a top up. The fields were grazed in February and were fertilised in early April.

Next they identified any strong grazing paddocks that could be closed up and these were given 20-30 units of protected urea per acre to give them a chance to bulk up. Other grazing paddocks also received fertiliser to boost grass growth.

Now they are planning their cutting dates. Yields in silage fields at present are ranging between 2,800 to 4,362 kg DM/ha. Paddocks on the grazing block will be needed in the grazing rotation so Eamon plans to cut these as soon as weather conditions allow, which is looking like the second weekend in May from the weather forecast. The silage field at 4,362t DM/ha will also be taken out then.

While Eamon and Donnchadh want to make quality silage, quantity is a priority too and the age old question arises; how can you do both?  On this point, it is vital to consider the yield of forage DM across the year as a whole, not just from a single cut. Figure 1 shows the effect of different first-cut dates on total grass silage DM and forage energy (UFL) yield per ha, in a two-cut system with a fixed second cut date in late July.

Effect of first cut date on total silage DM and UFL yield in a 2-cut system

Figure 1: Effect of first cut date on total silage DM and UFL yield in a 2-cut system

There was no advantage in total DM production to delaying first cut due to poor yield at 2nd harvest. In addition, first cut silage was lower in DMD and not suitable for growing cattle or autumn calved cows. Delaying second cut further for the later first cut swards would have reduced availability of autumn after-grass and negated any silage yield benefit.

From a cost perspective, delaying first cut would not result in significant dilution of land charge (due to similar total DM yield per ha), while contractor costs would be similar (particularly on a bale silage system). Management decisions around first cut silage yield should therefore be made on the basis of meeting DMD targets and improving annual grass tonnage per hectare, rather than focussing solely on the bulk of an individual cut.

Therefore the target will still be to cut the main silage fields before the end of May and they will be fertilised as soon as the field starts greening up again after cutting. Another option that Eamon and Donnchadh have is to fertilise the grazing block with extra nitrogen in the form of protected urea to increase grass growth and take out surplus paddocks for silage. First cut silage yields will be a good indication of what the next steps will be.

Eamon & Donnchadh's strongest silage field at 4.3 t DM/ha

Figure 2: One of the silage fields on the farm has a cover of 4,362 kg DM/ha and will be cut as soon as weather allows


The first 5 under 16 month bulls were slaughtered on 21st April. They were an average carcass weight of 433kg (range 406-454kg), graded U+3- and made €2410.20/head on average. The remaining bulls averaged 597kg on 15th April (range 546-683kg), and had gained 2.07kg/day since 25th March. Eamon’s target is to kill them at 720kg live weight and achieve a kill out of 55% to target a carcass weight of 400kg.

There are 5 autumn 2021 heifers for finishing this year and they weighed 493kg on 13th April.

The spring 2022 heifers (8) were weighed on 13th April and averaged 381kg, having gained 0.76kg/day since 6th February.

The autumn 2022 bulls (7) were weighed on 2nd April and averaged 317kg, having gained 0.92kg/day since 22nd January. They were weaned during this time and are now grazing in a paddock on their own.

The autumn 2022 heifers (11) were also weighed on 2nd April and averaged 288kg, after gaining 0.84kg/day since 22nd January. They have also been weaned and are grazing with the spring cows and heifers.

Finishing bulls remaining on the farm

Figure 3: Some of the finishing bulls remaining on the farm


Grass as measured on 2nd May and showed a farm cover of 861 kg DM/ha, which is slightly ahead of the target 700kg DM/ha for the time of year. The demand was 49kg DM/ha as 5 paddocks have been closed for silage, and the growth rate was 62 kg DM/ha. There were 18 days ahead.

20-30 units of protected urea/acre were spread in April on the grassland and the winter barley got 84 units of protected urea per acre.

Walking the farm weekly is helping Eamon and Donnchadh to watch grass growth rates and ensure that there is sufficient grass ahead of the cows, without running into a surplus. This has allowed them to react quickly to good growth rates and take out the 5 paddocks for silage to help their fodder supplies for next winter.

Grass wedge for the farm on 2nd May

Figure 4: Grass wedge for the farm on 2nd May