LIC | Heat Detection Tips

Heat Detection Tips

Up to 50% of cows won’t show a standing heat when they’re on concrete. That’s according to overseas-based research (Kerbrat and Disenhaus, 2004; Roelofts et al. 2005; Lyimo et al. 2000; Van Eerdenburg et al. 2002; Lucy, 2001), but LIC’s reproduction solutions team believes New Zealand farmers would do well to heed the message – and therefore do their utmost to undertake more paddock observations.

“Good mating starts with good heat detection. Getting it right can offer massive ‘bang-for-buck’ when pulled off correctly,” says Charlotte Gray, LIC reproduction solutions analyst.

“Cows that calve early to AB are likely to provide ideal replacements and are set up to deliver more milksolids the following year.“But heats need to be picked with accuracy, first time, every time; if the effort is put in, it’ll set up the farm up well for next season.”

“The best heat detection results are achieved by combining paddock observations with heat detection aids such as tailpaint and heat mount detectors (DairyNZ’s InCalf Book, p84).”



  1. Paddock Checks are free
    …but labour isn’t, so roster staff to keep them fresh and tuned-in to the task at hand. Also, create blocks in your day to get into the paddock: Once the cows have been munching for a minimum of two hours, head to the paddock. Cows that are full will start to show signs of heat, and well-fed cows will show stronger, longer heats.
  2. Look out where you're watching
    Overseas research (Kerbrat and Disenhaus, 2004; Roelofts et al. 2005; Lyimo et al. 2000; Van Eerdenburg et al. 2002; Lucy, 2001) shows about 50% of cows won’t display standing heats when they’re on concrete. Don’t sell the animals short by seeking signs of heat as the herd comes in to the yard or on to the feed pad.
  3. Maintain the tools
    To get the best out of your spend, keep heat detection aids and/or tailpaint well maintained. Take time to apply detectors correctly and check them regularly. Also allocate time for touch ups and maintenance of aids throughout AB.
  4. Free Heat Detectors
    Don’t leave the recently AB’d cows in the ‘next-to-the-shed’ paddock until afternoon milking. Get them back into the herd and allow the girls who are ‘coming on’ to join the party. Sit back on the bike with your mating app (or pen and paper) and note down the numbers.
  5. The more, the better – And the more, the easier 
    It’s easier to pick cows when there are more cows on heat in the same place. Strength and length of heats increases with the size of the sexually active group. Cows spend up to three-times the period involved in heat displays when there are two (or more) cows on heat compared to one.
  6. Pre-mating heats can be the pre-season warm up 
    Test yourself and your staff during the pre-mating period to train your eye, so you have a sense of what’s on and what’s not by mating start date. Use MINDA’s mating app or a chart to record the heat dates and associated cow numbers (highlight dates you’re not certain about). If there’s lots of highlighter on your paper before mating start date, a review of the process is a likely recommendation.
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