The camera provides a direct view into the calving pen. It offers a visual representation of the overall situation; however, direct observation remains essential. Internet-enabled cameras allow the feed to be streamed to mobile devices (mobile phones, laptops, etc.), thereby offering greater flexibility in terms of location. Using a camera can save a considerable amount of time, as it eliminates the need to travel to the calving pen. Automatic alarm functions are not yet ready for practical use. Several cameras may be required to view the entire calving area. The camera system must be suitable for use in barn conditions (dust, humidity, etc.). The camera position and lighting conditions (possibly an infrared camera for night-time viewing) must be taken into account.

A sensor is inserted into the cow’s vagina prior to the calculated calving date. The exact timing varies according to the manufacturer’s instructions and can range from approximately two weeks to a few days before birth. The sensor measures either temperature or temperature and light exposure. If the sensor emerges from the vagina during the birth process, the drop in temperature or the drop in temperature and light exposure is recorded. This triggers a notification. Depending on the manufacturer, this can result in a high number of false alarms, e.g. due to the sensor falling out without labour having started.

The birth detector at the base of the tail reacts when the tail is raised. During the dilation phase of birth, and often in the days leading up to it, this occurs even independently of defecation. Due to significant individual differences in behaviour, false positive alerts may occur even days before birth. Devices for this measurement can either be fixed at the base of the tail or attached to the base of the tail using a chest and belly harness. In this case, correct positioning must be carefully checked and regularly monitored to ensure that blood circulation to the tail is not impeded and that the devices do not fall off. If the fit is too tight, it can lead to the lower half of the tail becoming necrotic within a short time.

Depending on the manufacturer, a rumen bolus measures various parameters such as activity, rumination, temperature or rumen pH. To monitor calving, one of the indicators used is the drop in body temperature that occurs around 24 hours before calving. The bolus is administered to the cow using a bolus inserter and then remains in the reticulum for the rest of the animal’s life.

Movement activity can be monitored using pedometers, collars, ear tags or rumen boluses. Changes in walking and lying behaviour in the period leading up to calving trigger an alarm, which may indicate that calving is imminent. The advantage here lies in the ease of use and the secure positioning of the sensors. However, activity measurement as an indicator of calving is less reliable than other systems.

Rumination activity can be monitored using collars, rumen boluses or ear tags. In this method, a decrease in rumination in the period around calving is used as the basis for triggering an alarm. This method of monitoring is less sensitive than comparable systems for detecting calving.