Calving at two; eases management and frees up resources

Well grown heifers calving at two years will bring management benefits and free up the unit’s resources. Fact.

1. Management

If you have a block calving herd, then two year calving

  • allows the heifers to calve down in line with the rest of the herd, rather than having to hold them, for example for another six months until the next block calves
  • helps to maintain a compact calving pattern


2. Resources

Two year calving helps to:

  • Make the most cost effective use of feed ingredients: Feed Conversion Efficiency is highest in the first eight weeks of life after which it rapidly tails off. In the first two weeks, 100g of feed will give approximately 50g – 60g of growth, thereafter it dramatically falls during the first 12 months to approximately 9g of growth from 100g of feed
  • reduce bedding requirements
  • free up accommodation earlier in the rearing shed
  • reduce grazing requirements
  • reduce overall labour requirements

If you would like to know more about growing better heifers which in turn will improve your herd’s overall efficiency, then have a look at our resources.

The programme enables you to create your own heifer road map which sets individual farm objectives and helps you to track performance and continually review to ensure each animal is on target to reach puberty by 9 months, first breeding by 13 to 14 months, in calf by 15 months and calving on target at 24 months.

Measuring and monitoring

Achieving heifer calving targets

Is one of your herd targets to calve the heifers at 24 months? It’s an age regarded as the optimum in terms of the animals’ subsequent performance, however every farm operates its own unique system and this goal may not suit all units.

What is important is setting a goal for your farm, whether its 24 or 26 months, and sticking to it. Consequently, heifers must be monitored throughout the rearing period to ensure they are on track to reach the target set. That means a proactive approach is essential from day one – you can’t sit back and assume it will happen.

Regularly measuring and monitoring growth rates is the only way to ensure each calf is reaching your set target, and to reduce the variation within the replacement group.


1. Set growth targets: these will be individual for your farm based on the mature body weight of cows in lactation three and older; aim for at least double birthweight at weaning and then 55% to 60% of mature body weight at first breeding, then monitor each individual heifer during rearing to ensure they are meeting the required target. If they are not, then nutritional changes can be made.

2. When: measure animals regularly during the rearing period – at birth, weaning and when heifers are handled for routine management practises, for example for vaccination, worming etc.

3. How: weigh scales offer the most accurate measure and, if set up correctly in a race or crush, will be the easiest method. Alternatively, use a weigh band (girth tape) or height stick. Use the same measure consistently so that you can benchmark your results.


Check out the heifer target growth rates in the following table. Adjust accordingly for your unit based on the herd’s mature cow body weight, and your target age at first calving. Remember, heifers often require more than one service for conception, so first breeding must start more than nine months before the target first calving age.

Holstein Friesian heifers Age at first calving
Target age at first calving (months) 24 26
Average mature bodyweight (BW) (kg) 660 660
In calf (months) 15 17
Start breeding (months) 13-14 15-16
BW at breeding (55% mature BW) 370 370
Growth rate required (kg/day) 0.75-0.8 0.65-0.7