Farmers should be considering scanning cows that are yet to show signs of heat. If the cow is not a late calver, it may be a cause for concern.

These cows can be identified by still having their tail paint, or from records used to record heats and services.

Many dairy farms are three or more weeks into their breeding season. By now, a large number of cows – up to 90% of the herd – should be submitted for breeding.

However, cows that are calved 35 days or more, and are not showing signs of heat, should be examined to identify the cause.

Late-calving cows will take longer to show signs of heat, so there is no need to worry about these cows yet, if they are still to show any activity.


Some farmers choose to carry out pre-breeding scanning of their entire herd, or just some selected cows. This is usually done two or three weeks before the breeding period starts.

Others will wait until the breeding period has started before checking any cows that are not cycling.

Depending on what way you operate, the benefits of scanning cows cannot be overlooked, and if your heat detection methods aren’t up to scratch, then the chances of these cows not going in-calf are going to increase.

By carrying out scanning you will be able to tell what is going on and this will allow you to decide from there, whether the cow needs a washout, a hormonal treatment or just more time.

In general, farmers who don’t scan their herd before the mating start date (MSD) will scan any cows that haven’t shown any signs of heat roughly three weeks after breeding has commenced.

However, if you think that a cow isn’t right (due to a possible hard calving) then she should be checked immediately.

The sooner a cow is identified and treated the better, as this will give the cow a quicker and better chance of going in-calf.

By not identifying cows that are not in heat, the chances of them not going in-calf are increased. If it happens that they do go in-calf, you are looking at an increased calving interval and a shorter lactation period, which is what you want to avoid at all costs.