LIC | Heat Detection FAQs

Heat Detection FAQs

Do I need to get the tech twice a day or is once-a-day insemination ok?

Once-a-day AB is proven to be effective in NZ. Some DIY operators choose to AB in both the morning and evening for convenience. Studies show that there’s no significant difference in non-return rates for cows first noticed on heat in the morning or in the afternoon when both groups were mated the next morning.

If I mate a cow in the morning and she’s still in standing heat in the afternoon, should I mate her again the next day?

No. As long as she was truly on standing heat at the morning insemination then she’ll be fine. The length of standing heat can range from 6 to 24 hours. If she’s on standing heat the following morning again then put her up. If she remains on heat then get the vet to check her.


Why are paddock checks better than watching them as they come into the yard?

Recent overseas studies found that less than 50% of cows will display standing heat on concrete surfaces (Boyle et al., 2007; Kerbrat and Disenhaus, 2004; Roelofs et al., 2005; Lyimo et al., 2000; Van Eerdenburg et al., 2002; Lucy, 2001). Cows display standing heat more readily on dirt and pasture surfaces.


Are heifers harder to pick on heat? What is the length of time a heifer is on heat compared to a cow?

The length of standing heat can range between 6 to 24 hours and is affected by several factors such as the size of the sexually active group. While it’s often said anecdotally that heifers have shorter, weaker heats than cows, there’s little evidence to back this up. Overseas work suggests that the opposite is true with cows having shorter, weaker heats. It’s thought that this is due to age and milk production factors.

How long does semen last in a cow?
Fertile fresh liquid-stored semen can survive in the cow for up to 52 hours (Vishwanath and Shannon, 2000).

Does mixing different bulls’ semen in a straw increase conception rate?

The short answer is no. By mixing the semen of a low fertility bull with semen from a highly fertile bull, it’s possible that the ‘combined’ insemination might achieve better fertility than the poor bull’s semen would if used alone. However, it’s not going to be better than the more fertile bull.

Can I use aerosols and other pungent tail paints at the same time cows are being inseminated?
Semen is very sensitive to many chemicals, and is very sensitive to many things considered safe for humans. In the LIC semen labs staff are not allowed to wear perfumes or some deodorants for this reason. Semen is also very sensitive to sunlight, smoke and chloride fumes (such as the ones given off by Chloride of lime regularly used as a dairy shed cleaner).

The effect will depend on the amount of exposure. While the exposure may be small because semen is still inside the straw, avoiding using aerosol spray at time of AB eliminates all possible effect. If this has to be done, do it after all cows have been inseminated for the day. Once semen is inside the cow, it is not likely that aerosols will affect sperm survival.

It is best practise that cows should not be tail-painted until the semen is safely in the cow. The same applies to KAMAR® glue. This should not be an issue as it is usually best to wait until the next milking to reapply her heat detection aids otherwise they may become reactivated prematurely.


Do I need to trim the hair before I put a KAMAR® or Bulls-i® on, and how much do I take off? When should I do this?

It is not recommended that you trim hair before applying these aids, but do remove any loose hair, dirt or dust from the application site. However, do not do this too vigorously to avoid oils from coming to the surface and recommended this be done 24 hours prior to application, we recommend the use of any enclosed user instructions. In extreme cases where the winter coat is still present then the excess hair may be removed.

My KAMAR®s fall off the cows in hot temperatures. What should I do?

If you’re happy you’re doing the above preparation correctly then you may need to look at the amount of glue being used; too much can cause the aid to slip off before the glue can bind to the hair. Note that there is also a maximum length of time an aid should be used for (up to 30-35 days) and therefore the KAMAR® may be due for replacement.

Should we put the cows back into the herd after they’ve been AB’d?

Yes, it’s important to put the sexually active cows that’ve been drafted out for AB back into the herd as soon as you can as they’ll act as your heat detectors to spot the next girls that are coming on. The bigger the sexually active group, the more obvious the heats are and the easier they are to accurately pick. Cows that have a stronger heat are more likely to get pregnant because the timing of AB is more likely to be accurate (Gilmore et al., 2011).

My KAMAR®s get eaten by my R2’s what should I do?

The dye in a KAMAR® has a sweet taste to it and young stock can develop a liking to this. This behaviour should stop when they are older however you can purchase a spray from your local farm supply store or vets that is a foul-tasting anti-biting spray that you can apply over the aid.

Should I reapply tail paint straight after/during insemination? Or should I wait till the next milking?

Fumes can kill semen, so don’t tail paint while there are loaded pipettes not yet inseminated. As long as the AB session is complete, cows can be tailpainted, but you may need to retouch the paint on the girls still riding the next day. An alternative is to do them later in the day or the next day – whichever works best for you. KAMAR®s and Bulls-i®’s will need to be applied once the cow is fully off heat.

I’ve been told to put all my inseminated cows back with the main mob- why is this? As I would rather not.

This is important as these cows are the workers at helping identify the next cows coming on heat. Having a good sized sexually active group in the herd is important for accurate heat detection. ‘After insemination, return cows to the milking herd as soon as possible to encourage formation of new sexually active groups’- InCalf™ book page 84

Why do I have cows with tail paint rubbed off, but the KAMAR® has not been activated?

Tail paint can wear off for a number of reasons and in majority of cases it is due to the application or maintenance of the tail paint, check the position of the KAMAR® and reapply tail paint, if the KAMAR® position was incorrect then it may pay to inseminate, if the KAMAR® is in the correct position then draft and look for other signs of heat (the sexually active group drafted for mating may help with identifying whether she is on heat).

Paddock checks are a waste of time in large herds without a Protrack. What else can LIC do to help me?

You can use multiple heat detection aids to lift accuracy in the shed. The InCalf™ book states that herds using Heat Mount Detectors, such as KAMAR®s have higher heat detection efficiency. Paddock checks are very valuable regardless of the size of your herd. Heat detection devices are an aid to help assist heat detection and should not be used as the only form of heat detection. Use of the Mating App recording heats can provide you with a list for next morning’s mating. If pre-mating heats have been recorded in MINDA™ you can also run a ‘Cows due to mate’ report which will provide you with predicted mating dates.

What works the best KAMAR®s or heat patches?

KAMAR® and LIC Heat Patches are very similar technology and therefore it is more user preference, however if you are referring to a friction-type aid then there is a difference, as KAMAR® and LIC Heat Patches are for standing heats and have a built-in timing mechanism that requires a firm standing mount of at least 3 seconds to activate, whereas a friction-type aid can add another level of interpretation due to the friction occurring over multiple mounts and being able to be scratched off on other things such as tree branches.

Why can’t I know my non-return rate (NRR) anymore, by asking one of your techs?

The DataMATE™ platform can only store so much data and it is important to have the core functionality fully supported. That is why it was removed. Also your Farm NRR, which is the much better measure to use than other NRRs is available on the Fertility Focus report on (MINDA™ Reproduction under reports tab). This is a more representative NRR to use as it includes all the short returns, which were excluded from the old DataMATE™ NRR.

Will my NRR ever appear on MINDA™ on the web?

Yes, the Farm NRR appears on the Fertility Focus Report in MINDA™ reproduction, as it always has. You need to remember, however, that NRR is a poor indicator of success or failure of insemination- you are much better to get conception rate results, generated from aged pregnancy testing done between 35-122 days of conception.

My vet and other farmers have told me inseminating a cow 24-28 days after her original insemination is dangerous to the potential pregnancy and may cause miscarriage, 15-25% chance. If I feel she really is on heat 27 days after her first insemination, what should I do? Should I mate her?

It’s true that re-inseminating a cow that is already pregnant poses some risk of pregnancy loss. For subsequent inseminations you need to be certain that she is on heat. Look for reasonable signs of heat and if she is on standing heat or her heat detection aid is fully activated, inseminate her. If you are not sure, draft her out with the bulling cows and observe for further signs of heat, then decide if you should inseminate her. You can ask another experienced person for their opinion if you are not sure. If you’re not sure, record a ‘?’ beside the date on the mating chart to refer to later on if necessary.

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Boyle et al. 2007. The effect of rubber versus concrete passageways in cubicle housing on claw health and reproduction of pluriparous dairy cows. Applied Animal Behaviour Science, 106, 1-12.
Gilmore et al. 2011. An evaluation of the effect of altering nutrition and nutritional strategies in early lactation on reproductive performance and estrous behaviour of high-yielding Holstein-Friesian dairy cows. Journal of Dairy Science, 93, 3880-3890.
Kerbrat, S., & Disenhaus, C. 2004. A proposition for an updated behavioural characterisation of the oestrus period in dairy cows. Applied Animal Behaviour Science, 87, 223-228.
Lucy, M. 2001. Reproductive loss in high-producing dairy cattle: where will it end? Journal of Dairy Science, 84, 1277-1293.
Lyimo et al. 2000. Relationship among estradiol, cortisol and intensity of estrous behaviour in dairy cattle. Theriogenology, 53, 1783-1795.
Roelofs et al. 2005. Pedometer readings for estrous detection and as a predictor for time of ovulation in dairy cattle. Theriogenology, 64, 1690-1703.
Van Eerdenburg et al. 2002. The relationship between estrous behavioural score and time of ovulation in dairy cattle. Journal of Dairy Science, 85, 1150-1156.
Vishwanath et al. 2004. Effect of timing of insemination of dairy cows with liquid semen relative to the observation of oestrus. Proceedings of the New Zealand Society of Animal Production, 64, 140-142.
Vishwanath, R., & Shannon, P. 2000. Storage of bovine semen in liquid and frozen state. Animal Reproduction Science, 62(1-3), 23-53.

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