Effectiveness of a Wireless Transmission System in Searching for Hidden Calves in Grazing Land

Searching for hidden calves in grazing lands is a great burden for herders, although the hiding behavior of calves is important in animal welfare. Recently, wireless transmission services for mountain rescue have attracted considerable attention and the services have branched out into the pet rescue field as well. The transmission device does not utilize global navigation satellite system (GNSS) or internet communication, but only emits a radio signal that can be received by a specific receiver within a specific distance. Therefore, the device is lightweight and can be used for a relatively long time without recharging. We evaluated the effectiveness of the wireless transmission system in reducing the labor required for herders to search for hidden calves in grazing lands. The search trials were conducted in four paddocks (4.8–5.1 ha), which were located on an uneven terrain in the mountains, consisting of pasture and wood sections; therefore, these paddocks were under poor visibility conditions for cattle search. Using a dummy calf that imitated a 1-week-old calf, we performed a total of 40 search trials (five trials each with and without device support in each paddock), and compared the moving distance (search distance) and searching time, with and without device support. Moreover, we conducted 30 search trials using three Japanese Black calves fitted with the devices, to demonstrate the effectiveness of the device support. In the search trials involving dummy calf, the use of the device significantly reduced the moving distance and searching time. In the 30 search trials involving actual calves with device support, hidden calves were found using only the device's indications. There were no device failures or the collars falling off. Therefore, the wireless transmission device is useful for searching for hidden calves in grazing lands.