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Calving heifers at two years of age

Calving heifers at two years of age

Beef Specialist Martina Harrington gives advice on producing beef sustainably.

From ICBF figures we can see only 23% of heifers are calved between 22 – 26 months of age, a very low figure. The majority are calving > 30 months. This is despite the advantages of:

  1. Economics: The most profitable age to calve heifers is 24 months. Research at Teagasc Grange shows that for a 50-cow herd with a 20% replacement rate, each additional month that calving is delayed costs €490 or €50/heifer per month.
  2. Environmental: the reduction in carbon footprint is 0.14 kg CO2e/kg beef carcass for each month reduction. This equates to a 1.6% reduction per month, so reducing from 30 months to 24 will be almost 10% reduction per kg beef.
  3. Longevity Heifers that calved for the first time at 23 to 26 months had greater survivability in herds with almost 40% reaching fifth parity, compared with only 4% of those that calved for the first time at 31 – 35 months - Figure 1. most farmers would be of the opposite belief
  4. You will have less groups of stock on the farm, so labour will be reduced
  5. You can increase the rate of genetic gain within the herd

Keith Fahy, Teagasc caught up with Pearse Kelly at #Ploughing2022 to get an insight as to why farmers should calve beef heifers at 24 months instead of 36 months. Pearse explains how there's a huge difference in profitability in herds that calve their heifers down at 2 years versus 3 years - sometimes 75% difference in profitability. Calving down calves at 24 months also reduces the level of carbon emissions.

Figure 1: Comparison of national statistics on the performance of 131,077 beef heifers calved for the first time, between 23 and 40 months of age (supplied by ICBF). 

Age at 1st calving - monthsAverage subsequent calving interval - days% Calving for a second time

Average calving difficulty of bulls used

Heifer calving unassisted

Mortality at first calving 

Heifers reaching 5th Parity
23-26 383 82 4.7% 50% 3.2% 39%
27-30 394 82 5.1% 53% 2.8% 20%
31-35 392 87 5.2% 58% 2.6% 4%
36-40 386 86 5.2% 57% 2.0% 0%

From talking to many discussion groups, the main reasons given are that – the heifer is not heavy enough, she will be stunted, she won’t go back in calf etc.  Yet we know many farmers are calving heifers successfully at two years of age, so how do they achieve this?

Read what Future Beef farmer Ger McSweeney is doing