Calving heifers at 24-months-of-age has raised some concerns among farmers in the past. There are many factors which deter farmers away from breeding heifers at the age of 15 months.

Many farmers have questions on calving at 24-months-of-age. These include:

  • Will this stunt the growth of the heifer?
  • Will there be difficulties at calving?
  • Will she go in calf for a second time?
  • Will this result in a smaller calf?

While these are all legitimate questions and queries, it must be noted that farmers who calve heifers at 24-months-of-age operate more profitable farms.

Calving heifers, in the spring time, at two-years-of-age is no easy task and requires some precise management.

Now is the time to select replacement heifers. According to Teagasc, weanling heifers from good cows that have achieved 1.1kg/day or better – since birth – should be selected.

Weighing heifers on regular occasions is an essential component of the management process. At weaning, the heifers should have weighed 260kg. At housing (mid-November), heifers should be 300-320kg.

A poor performance over the first winter will hamper any chance of the animal meeting weight targets at breeding (15 months).

According to Teagasc, heifers need to achieve an average daily gain (ADG) of 0.6/kg/day over the housed period.

However, this year, with the changeable weather experienced during the summer, many farmers have harvested crops of poor-quality silage. By testing the quality of their silage, farmers can make adjustments in the level of concentrates being fed.

Farmers with good-quality silage (68-70% DMD), Teagasc says, should be feeding 2kg of concentrates in order to achieve an ADG of 0.6kg/day. Farmers feeding poorer-quality silage may need to increase concentrates by 1-2kg/day.


Weanling heifers in poor body condition should be fed meal ad-lib from housing until a body condition score (BCS) of 3.5 is achieved. Care must be taken not to overfeed heifers, as this will lead to increased difficulties at a later stage.

Farmers also should ensure that all heifers are free from disease and parasites. Correct ventilation and feed space are very important to ensure nothing inhibits the potential growth of the animal.


In spring, an early turnout is essential (weather permitting) to avail of compensatory growth. According to Teagasc, typical turnout weights should be 380-400kg for continental-type heifers.

Following a successful early turnout in spring, heifers should receive two vaccinations approximately eight weeks ahead of breeding – one for Bovine Viral Diarrhoea (BVD) and one for Leptospirosis.

In addition, four-to-six weeks on good-quality grass should leave heifers weighing 420-440kg at mating (60% of mature body weight).