LIC | Get Fired Up for Heat Detection

Get Fired Up for Heat Detection


Many of you will have already started the most important job of the entire farming season - getting cows back in calf.  

How well mating goes will impact on your calving pattern and milk production over the next 2-3 years.

As a quick refresher, the mating targets that you should be aiming for are:

  • Pre-mating heats of >85%
  • 3-week submission rate of 90%
  • 3-week in-calf rate of >60%
  • 6-week in-calf rate of 78%.
  • 12-week empty rate <6%

These targets may seem high for some, but there are farms achieving and surpassing them. 

The value of having a tighter calving spread comes in the value of getting more days in milk (DIM), and you also get more AB heifer calves to select from and possibly sell any surplus.  Financial analyses of farms show a strong link of DIM with farm profitability.

Review of calving spread

One of the best MINDA reports you can use is the calving spread graph by age group.  This shows each of the age groups of your herd and how well they have calved for this spring just completed. You can find this under Reports > Calving Reports > Calving rate report.  Have a look at your herd’s performance and see if you have a group that is below the blue line.  Take appropriate action if required.


Hopefully you have a written mating action plan of what happens on what dates.  If you haven’t then seek help to get a plan in place now to avoid mistakes.  It is not surprising to find that farmers who have a detailed and dated mating plan achieve better mating performance than those who don’t plan.

Heat Detection

For many who have already started mating, heat detection has now got to be the major priority and time investment of each day.  On a $5.00 pay-out each missed heat is worth $160 per cow (excluding the value of more heifer calves).

Too often I see that this part of the big mating jigsaw is lacking.  This all means that good systems and staff training are vitally important.

The more time spent observing cows in the paddock, the higher your submission rate will be and the higher the chance of a better 6-week in-calf rate.  To maximise your submission rates consider the following:

  • Do not just rely on reading tail paint or detection aids in the cowshed.  
  • To identify those quiet and short heats, spend 20 mins 2-3 times a day in the paddock.  Two hours after cows have had a new break of grass, as activity is often highest then, and when getting cows out of the paddock before milking.
  • Try to observe cows as quietly and naturally as possible.  No motorbikes or dogs.
  • Draft any of these suspect cows out prior to the AB technician arriving into the cycling group, and observe behaviour of these uncertain cows.
  • Return mated cows to the herd after insemination to help identify the next day’s cycling cows.  This becomes very important in the second round of AB in smaller herds.
  • Re-tail paint the following milking with a different colour.
  • Minimise the number of people responsible for heat detection, as this minimises excuses and mistakes.  One trained person per herd.

Staff training

Sometimes we assume that everyone is on the same page as us and can pick bulling cows, or know how to correctly apply tail paint, but often this is not the case.  

If you have new staff, take them to a training day and go through the farm mating plan. Ensure that everyone knows how to pick bulling cows and understands the farm’s systems for recording heats, submitting cows for AB and re-tail-painting cows.  

Two hours invested here could pay thousands of dollars in returns!  

Bull management

Your bulls required for the yearlings and the herd should be well sorted by now.  All bulls must be BVD tested and vaccinated.
The yearlings will need 1 bull per 20 yearlings.  The main herd will require enough bulls to cover no more than 1.5 cows to service per day (30:1 ratio).  You will also need bulls to provide rest and rotation so they don’t become tired or lame.  Every farm differs in this level of cover, but two teams of bulls rotated every 24 hours works well.

If you are unhappy with your herd’s past mating performance, be proactive and seek some help now to ensure you are not complaining about a slow calving next spring.

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