A small job that could pay dividends for years
John McCabe, Advisor on the Teagasc-Aurivo Joint Programme, reminds dairy farmers that a small investment of time this autumn could pay dividends in years to come.
I have been seen results of heifer weights from numerous farmers over the last month or two. The results in some cases are not good at all. This seems to be an ever-present issue, with some years better than others.
In 2024, I carried out some work with around 50 farmers that weighed their weanling heifers. The results were interesting: 25% of heifers were more than 20kg behind target at six months of age which is a significant percentage. The really important finding from the project, however, was that roughly 4 in 10 farms had a significant enough issue and the other 6 only had a handful behind target, if any.
The importance of weighing
Animals can look fine to the eye but it’s important to get them up on the scales to check. If they are light and don’t catch up, this can result in lower conception rates next spring.
If they don’t catch up next year, they could be light first calvers. This is not good for cash production. Heifers that come into herd light don’t milk as well, nor do they last in a herd as long. Additionally, a small-framed animal does not do as well in the factory either. The advice is simple for all farms – weigh your heifers.
If you have never weighed your heifers before, there are contractors that can bring their scales and weigh animals with you. This is a super service, especially for those that are short staffed or farming on their own. Alternatively, a lot of co-ops have a scales that you can rent for the day for a small fee (roughly €50). If you search ‘Weighing ICBF’ on the internet, you will find a page that has a list of weighing technicians/contractors that can come to your farm, as well as a list/map of locations where scales can be rented.
No two heifers will be the same when they grow into mature cows. One could be 550kg as a cow and the other could 700kg. Needless to say, the heifer predicted to be a bigger cow will have to be heavier today than heifer that will turn into the smaller cow.
ICBF Herdplus has a fantastic facility to get over this complication. It highlights each heifer’s current weight versus what they should be at on the day of weighing. The Heifer and Cow Weight profile can be found when you log into Herdplus, and is worthwhile looking at on the computer, even if you use some of the phone apps for stock management.
I have included an example of this screen from a client’s farm where the weanling heifers are behind for various reasons. The heifers on or above target are in white, the heifers behind target are in varying shades of red with the animals that are the furthest behind in bright red.

Underweight heifers
The good news is that if you catch the problem early, it is easily rectified. You can supplement more meal now to the animals that need it. You can make sure that they get lots of grass and are not in a field for too long.
Give lighter animals more space in the shed over winter, with plenty of feed space, and offer them top quality silage along with some concentrates in order to help them catch up. Make sure dosing is up to date and have a discussion with your vet if you think that parasites may be a problem.
