Authors: Margareta Emanuelson & Anders Herlin (SLU) - Date: August 9, 2018
In Sweden there has been a severe drought during spring and summer of 2018. This has led to a dramatic shortage of pasture and all types of forages. Therefore, farmers have to look for alternative feeds. A solution could be to let the cows out in the deciduous forest to graze leaf, lily and grass. But the farmer needs to keep track of the animals - daily supervision is a requirement in Sweden, according to the law.
One example of how this can be implemented is now being practiced at a big dairy farm in Sweden, Wapnö. Some 100 ha of forest has been fenced and around 200 heifers has been let out in the forest to graze. This is a costly solution, but what to do when there is no feed.
To be able to track the heifers every day, some of them have been provided with GPS-units. They use the same robust equipment’s and technology that today is being used for keeping track of reindeers in the north of Sweden, Pellego, sold by Followit. It is important that the units have long duration time (long battery time), that several positions are determined per day, about once an hour, to avoid the risk of missing positions due to signal shadowing of satellite signals from the tree coverage. Of course there must be good contact to antennas, like the GSM-net or local antennas in the area.
The following recommendations should be considered: The transponder should be placed on the animal´s neck to obtain a good chance of receiving the satellite signals as well as programming the GPS unit to determine several signals a day to avoid missing positions. The battery capacity and the frequency regarding the positions are crucial factors for the robustness of the equipment: the more positions that are determined per day, the longer battery life is required. New innovations regarding power, battery life, and adding on sensors that supervise the status of the animal (health, fertility) are entering the market which can make this technology more useful in various situations and needs.