News & Advice

Heat detection gets harder in the second round

Nov 6, 2019 | Dairy, Dairy Farm Reproduction

Katrina Roberts, Herd Health Veterinarian, Anexa Vets

Heat detection gets harder in the second round, so you have to work smarter and harder to find them! 

Six things to consider in the second round:

1. The group of cows on heat is smaller
If you are on target in the first 3 weeks of mating, then over 50% of your cows will be in calf at the end of week 3. It may seem obvious but this means there are less cows cycling each day and of course the sexually active group is smaller, which means there are less cows to mount other cows, less cows to rub off tail paint and less cows to set off heat detection aids! If you are aware of this, then your heat detection in the second round can ramp up. You could:

  • spend longer in the paddock observing the cows, 
  • start doing paddock checks if you weren’t before, 
  • apply a second heat detection aid (such as a Scratchie® or KAMAR®), 
  • pay close attention to the records and therefore the timing that a cow should be returning to heat. 

2. Make the best use of AB records
Now is the time to make use of the mating records to check if cows are due back on heat on a given day (your wall chart is a great way to track this).

3. Is the cow truly on heat?
Cows that are inseminated when they are already pregnant can lose the pregnancy. For these return cows we need to be sure they are due back on heat and have definite signs of being on heat (tail paint rubbed, seen standing or heat detection aid gone off). Have a clear plan if you are unsure about a return for example draft her out with the other AB cows and observe the interaction. 

4. CIDR cows often have strange return intervals
Cows that have been non-cyclers often have weird return intervals, so you do need to be watching out for these cows all the time. This is because non-cyclers respond to the programme at different times. Remember the CIDR programme we use is trying to mimic a normal part of the cow’s cycle and ‘kick start’ these non-cycling cows back into gear. However, some cows don’t respond to the hormones straight away and end up having short cycles (<17d) or long cycles (>24d) as they get themselves started up. 

5. Is putting the bulls in early a good idea?
If you really feel like you are missing return heats, then there is always the option of putting the bulls in early BUT this is not a decision to be taken lightly, as you need to be sure you have enough bull power to cope with the extra non-pregnant cows, your bulls are on farm and ready to do the job and next season you can accept a smaller number of keeper calves. 

6. Not long until it’s over – but still time to make a difference
Tell yourself now is the time that is crucial – if you are putting the bulls in with the herd in a couple of weeks, you are now on the homeward stretch – accurate detection of the returns will impact your 6 week incalf rate, your number of keeper calves and your days in milk next season – so dig in, stay focused and keep up the good work.

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