Trying to choose between 18-month and 24-month beef

The calving season is almost upon us at the Derrypatrick Herd in Grange, with the first females due to calve on January 31.

At present, mature cows and replacement heifers are currently being offered low digestibility (60 DMD) second cut silage only. Cows were being supplemented with 0.5kg of concentrate up to the first week of December.

At that time, females were condition scored and based on the results it was decided that silage alone for the remainder of the housing period would allow them to reach the target body condition score (0-5) of 2.5-2.7 at calving.

The progeny are currently being offered first cut (72 DMD) silage ad-lib, plus concentrate daily. Steers and heifers are being offered 1kg of concentrate per head per day.

Bull progeny are currently being offered 2kg of concentrate per head per day plus first cut silage ad-lib.

There are also bull weanlings being fed in the Derrypatrick Herd this winter – more on that later.

As mentioned in previous articles, we have shifted our mean calving date forward by an estimated two weeks to February 28. We estimate that 75pc of the herd should be calved within the first eight weeks of calving.

The objective of advancing the calving date by two weeks is to facilitate earlier turnout of cows and calves. However, this will be largely dictated by weather conditions.

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Like much of the country, we have had very high rainfall over the last few weeks and paddocks are now saturated.

Ground conditions will have to improve significantly over the next few weeks to allow us to achieve an early turn out (late February to early March).

Recent mild temperatures have improved grass growth during the winter and should result in an increase in grass supply for spring grazing.

But the frosts over the past week will have a negative effect on the average farm cover or grass supply that has built up over the winter.

In 2013, we will be examining the difference between 18-month bull beef, as has been practised on the Derrypatrick Herd for the past two years, and a 24-month steer beef system.

For this reason, half of the male calf crop from 2012 have been left entire for finishing as bulls in the autumn of this year and the remaining half were castrated (post-weaning) for steer finishing in spring 2014.

At the moment, average daily gain for the winter period, across males and females, stands at 0.72kg.

Although the slaughter age and finishing period for the heifers will not change (20 months at 315kg), there are a number of differences between these two production systems.

The current Derrypatrick 18-month bull system includes approximately 100 days at pasture plus a 100-day finishing period, when concentrates are fed ad-lib.

Total concentrate input for the finishing period is typically 1,000kg.

The main advantage of this bull system is that it allows us to produce cattle with heavy carcass weights at a relatively young age, while also reducing feed costs by incorporating a period at pasture.

In addition, this system reduces stocking rate in the middle part of the grazing season when the bulls are housed in late June.

It also makes more efficient use of facilities, as bulls are housed during the main grazing season when sheds are otherwise empty. This allows for increased cow numbers as, on average, progeny are on the farm for a shorter period.

One of the main disadvantages of this system is that we are selling beef in the autumn period, when beef supply is relatively plentiful and beef price is typically lower than in the spring.


The 24-month steer system, on the other hand, will require 4kg of concentrate, plus ad-lib first cut silage, over a period of between 130-150 days.

Total concentrate input for the steer is estimated to be approximately 600kg. However, they will remain on the farm for longer, with expected carcass weights slightly lower when compared to the 18-month bull system.

Additional housing will be required for the second winter.

The main advantage of producing steers in early spring is that beef price is normally higher and steers can also be sold on the QPS grid.

For commercial farms, a spring sale date has the benefit of spreading out cash income, thus improving cash flow on the farm.

Next year, once all the animals are slaughtered, we may be able to shed some light on the benefits of either system in terms of profit.

Denis Minogue is the herd manager of Teagasc's Derrypatrick herd at Grange, Co Meath.

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