Understanding the calving curve and setting the alert level

Each animal fitted with a Vigivel sensor has its own curve, which shows how its calving probability changes over time. You choose the level at which you are notified: between 60 and 95, with 75 by default and 65 recommended for heifers.

This article contains the following sections:

Reading the calving curve
When the alert is triggered
The temperature curve
Changing the alert level
Choosing the alert level
Setting rules

Reading the calving curve:

Time is read from left to right: the right-hand side corresponds to the most recent hours. The height of the curve indicates the calving probability, from 0 at the very bottom to 100 at the very top.

The sensor takes a measurement every quarter of an hour and sends its last four measurements once an hour to update the curve. The curve therefore moves forward in steps rather than continuously.

Your alert level appears on the same graph.

Calving probability curve with the alert level

When the alert is triggered:

The sensor calculates the calving probability every quarter of an hour. As soon as it exceeds your alert level, the sensor sends the alert immediately, without waiting for the hourly transmission of measurements: the text message or call is sent straight away.

The hourly transmission is only used to update the curves in the app. It never delays an alert.

If the probability is still above your alert level 3 hours later, a second text message is sent to you.

The temperature curve:

Temperature is included in the probability calculation, and it is also displayed separately in the app.

This is not body temperature
The measurement is taken on the surface, at the tail. It gives a useful trend, but varies by 1 to 2 °C depending on whether it is hot or cold in the building. Do not interpret it as the animal's internal temperature.

Changing the alert level:

To change a sensor's alert level:

Select the sensor concerned.
Tap the value displayed, for example 75.
Choose the desired level.
Tap Confirm.

Changing the alert level in the Vigivel app

Choosing the alert level:

Level	Effect
Low 60 to 70	You are notified earlier and miss almost no calvings. On the other hand, you receive alerts that lead to nothing: a simple rise in temperature or an animal scratching itself is enough.
65 heifers	The recommended setting for heifers, whose calvings require closer monitoring.
75 default setting	The right balance between the number of alerts received and the risk of missing a calving.
High 80 to 95	You are disturbed much less, but a quick calving may be reported too late, or not at all if the curve never reaches this value.

Setting rules:

Rule	Details
Possible values	From 60 to 95
Frequency of changes	Once every 24 hours
Time before it takes effect	Up to 1 hour, the time it takes for the sensor to communicate
Scope of the setting	Sensor by sensor: there is no common setting for the whole farm
Sensor on standby	The setting is kept
Sensor switched off	The setting returns to 75

During synchronisation
Until the new setting is active (up to one hour), it is displayed with an arrow in the app.

Alert level being synchronised, indicated by an arrow

Reading the calving curve:

When the alert is triggered:

The temperature curve:

Changing the alert level:

Choosing the alert level:

Setting rules:

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