In recent weeks, heifer calves have reached a significant milestone as they surpassed the six-months-old mark.

This is a noteworthy milestone for a heifer calf and can be used to determine how they are developing, and whether they are ahead of, or behind their growth targets.

Many farms determine calves' target weights by finding out the mature weight of cows within their herd and then working back.

For example, if your average cow weight is 600kg, at six-months-old your calves should be 30% of this weight which is 180kg.

However, an easier way to determine what a calf's mature weight should be is to look at their maintenance sub-index figure - which has a strong correlation to mature cow weight.

Based on the economic breeding index (EBI) maintenance sub-index figure, a calf’s mature cow weight can be determined.

Using this figure you can determine the weight this calf should be at six-months-old.

Achieving the development targets of your heifer is important to ensure they are at the right weight ahead of breeding in May 2023.

These six-month-old calves are future animals in your milking herd and you want to ensure they are in the ideal condition.

Heifers that are behind target may have fertility issues, meaning they may not go in-calf and you will have lost the time and money you have invested in them.

It is also important to note that you should focus on each individual calf and not the group average.

The group average can be misleading and could potentially hide a number of calves that are behind target.