Hot on heat detection

25 September 2019

Herd with different tail paint colours

Samantha Tennent, InCalf developer, DairyNZ

Determining which cows to submit for insemination might be one person’s responsibility, but the entire team can contribute to successful heat detection. I like to think about heat detection in three parts: plan, observe, and monitor.


My advice is to start by reviewing last season’s performance to determine this season’s approach and to identify opportunities for improvement. It really helps to utilise your vet, breeding companies or advisers to formulate a plan that works for you.

Never underestimate the benefit of talking the plan through with your farm team to ensure everyone understands who does what, when, and what to look for. It helps to agree on a system to record numbers of cows spotted on heat.

Sometimes it’s the basic stuff that can make all the difference, such as ensuring your heat detection kit is well stocked with tail paint and heat detection aids. DairyNZ’s InCalf programme recommends a combination of paddock observation, tail paint and heat mount detectors to cover all bases and remove any guess work.


Sometimes just watching your cows can pay dividends. And even better is if your whole team know what to look for, how often, and where to monitor the cows.

The best opportunity to seek cycling cows is to spend time watching the herd’s behaviour after they’ve had a good feed. If she is standing to be ridden, she’s on heat. If she’s doing the riding or hanging out in a sexually active group, she’s likely to be coming on heat. Knowing your cows is key and when you spot they’re not in their normal routine, for example in a different milking order, it’s a good sign they may be cycling.

When deciding whether to submit a cow or not – in the case that her tail paint or aid is unclear – my advice is to refer to any recorded cycling behaviour for more confidence in your cow selection.

If a cow’s heat status is questionable, it helps to mark it on the records in case she’s detected again within a short timeframe. Check her last recorded heat and interval between heats; if not in the normal range, check if the previous recorded heat had a question mark or if the current one is questionable.

If there are an increasing number of cows you aren’t sure about you may need to review your methods.


Monitoring heat detection performance during mating means you can quickly make adjustments. And remember, you’re not alone. There are plenty of people to offer you advice if you have any concerns.

DairyNZ’s InCalf programme

InCalf is a learning package of tools and resources aimed at improving herd fertility and heat detection, visit

For more information visit



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