Heat Detection Starts Now!


| Cattle & Dairy

| Mar 23, 2023

Cows Breeding

Breeding for Spring calving herds is due to kick off in the next few weeks. With that in mind we take a look at  heat detection and pre-breeding checks  before the season gets started. 

What is a heat?

Heat or Oestrus refers to the period of time whereby the female exhibits significant behavioural changes and displays mating receptivity. Oestradiol, produced by the dominant follicle, is the primary signaller to the hypothalamus in the brain to induce behavioural oestrus, in the presence of low levels of Progesterone. The primary sign of oestrus in the cow is referred to as standing heat whereby the cow stands to be mounted by other animals in the herd or by a bull.

However, research has suggested that not all cows display standing heat, commonly referred to as silent bullers or cows who have silent heats. 
As not all cows that go on to ovulate display standing heat, accurate oestrus detection can be difficult. However, there are many secondary characteristics of heat behaviour that cows display when under the influence of oestradiol and oestrus behaviour expression. The following are the main signs of heat in cows:

Primary Characteristics

Register your calves in 30 seconds or less, on the go! Allowance of mounting or “standing heat” 

Secondary Characteristics 

Register your calves in 30 seconds or less, on the go! Mounting from other cows

Register your calves in 30 seconds or less, on the go! Restlessness and bellowing 

Register your calves in 30 seconds or less, on the go! Vulval mucus 

Register your calves in 30 seconds or less, on the go! Metoestrous bleeding 

Register your calves in 30 seconds or less, on the go! Hair and skin abrasion and dirt from mounting behaviour

Register your calves in 30 seconds or less, on the go! Sweating, drop in milk (dairy cows) and drop in rumination


Pre-Breeding Scan

To get a better idea of a cows reproductive status, many farmers opt to carry out a pre-breeding scan on cows. A pre-breeding scan is ideal for confirming uterine involution has occurred and cows have returned to their pre-pregnancy uterine state. Dairy Cows should return to cyclicity from about 42 days post calving, whereas beef cows will cycle later if they have a calf at foot from about 55 days on. Cows that require attention will also be highlighted during this scan. For example anoestrous or non cycling cows as well as cows currently suffering from uterine infection. In heifers, it can identify animals who have immature ovaries who may not be suitable for breeding. The scan will also identify where the cow is in her cycle so you will have a better idea if she will come into heat soon. This is also useful to know if you plan to synchronise animals, which will be covered in a later post.  Phases of the bovine estrous cycle

It is important to identify potential issues so that they can be addressed correctly before the beginning of breeding. 

For example, anoestrous cows (non-cyclers) are often not picked up until they have not been submitted for AI. This can be up to 3 weeks. It will be harder to identify non-cyclers if a bull is running with the dairy herd or with sucklers and these cows are often missed. If a cow is experiencing an issue returning to cyclicity, there are many drug protocols available. But in order to identify the correct protocol required a scan is recommended. For example, an anoestrous cow has no functional corpus luteum therefore drugs like prostaglandins will have no effect and a full progestogen based protocol is a better option based on veterinary advice. Other issues can include cystic ovaries which will also need intervention. 

For sucklers, having a suckling calf at foot can have an effect on the fertility status of the dam due to the calf-dam bond. A way around this is to limit suckling to morning and evenings. Alternatively, a progestogen protocol can be used to restore fertility in most cases> Again speak with your veterinary practitioner to find the right protocol for your herd. 


Prebreeding Body Condition Scoring

Body Condition Scoring (BCS) is a technique used to assess how thin or fat a cow is on a scale of 1 to 5, where 1 is extremely thin and 5 is extremely fat.

The incorrect BCS can have an adverse effect on the different stages of pregnancy. For example, if BCS is too high there can be issues at calving such as dystocia as well as increased risk of milk fever. On the other hand, a cow that is too thin can have trouble cycling or holding a pregnancy. Additionally, too low BCS can result in a reduction in milk supply. Dairy cows should be at a target BCS of 3 at mating. 

For sucklers, 2.5 is the generally recommended BCS at breeding. 


Heat DetectionUntitled design (6)-3

Heat detection can be carried out in a number of ways. 

  1. Observe Cow Behaviour: as well as physical signs of heat as discussed above
  2. Use Heat Detection Aids: There are several aids available to help with heat detection, such as tail paint, chalk, electronic heat detection systems, and activity monitoring devices.
  3. Train Staff: If you employ staff on farm ensure they are adequately trained  on proper heat detection techniques and encourage open communication to ensure that all signs of heat are being identified and recorded.
  4. Keep Accurate Records: It’s important to keep accurate records of each cow’s reproductive history, including heat dates, breeding dates, and pregnancy outcomes. This information can be used to identify patterns and improve reproductive management. 

Heat Recording

PGP_0602_1TomHerdCows-1Another way to identify issue cows is to record pre-breeding heats. The absence of such can indicate a cow is not cycling.  Ideally for best conception rates cows should be bulled from the second heat onwards for early calvers. Recording first heats allows enough time for uterine involution, this is not always practical for late calving animals as in order to keep tight calving patterns, so at least 30 days after calving should be observed before breeding. 

If you record a heat observation in Herdwatch you will receive a push notification in 21 days time letting you know that the cow should be in heat today. You will see a list of females in heat on your Watchboard. This gives you the best chance to get your cows back in calf as soon as possible.


Heat observations can be recorded easily by following these steps…

>Tap Breeding
>Tap the Orange Plus Button (+) in the bottom right hand corner
> Tap Heat Observation
Set your reminder in days
>Set the number of cycles you want to be reminded for (i.e.21 or 42 days)
> Tap Next
Select the animal in heat
> Tap Save

When the animal(s) is due, you will receive a push notification and she will appear in the Watchboard under Heat Due Today. So you know to keep a closer eye on her!

The Watchboard will remind you which cows are due to repeat to ones that may be on heat based on the information your record.
When heat observations or serves are recorded into Herdwatch, the app will remember the dates and use the Watchboard to remind you when they are due to  repeat. Herdwatch will send you a daily push notification when you have events on your Watchboard that needs attention. 

The Watchboard covers two main are for breeding records:

  1. Watch for Repeat – The Watch for Repeat view shows a list of cows who need to be watched for a possible repeat as they were served between 20 and 22 days ago.
  2. Heat Due Today – This view will show any animals that are suspected to be on heat from a heat observation task. This is mainly used in the weeks leading up to the breeding season start date.

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The power of having this information in the Watchboard is that it will send you a daily reminder (in the morning) that there’s cows due to repeat or due to be bullying so you never miss a chance to get your cows in calf again!

You too can join over 18,000 other happy farmers saving time on farm paperwork and managing their farms more efficiently by downloading the Herdwatch app today.



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