1990 Volume 35 Issue 4 Pages 340-349
In the snowy area of Japan, the snow damage to the fences has been often found and all farm management costs on the public pastures has been oppressed by the fence maintenance cost. The fences of four types were tested for three years to grasp to the fences being low cost and little snow damage. Type I was the conventional fence with 4-barbed wire of the height of 30, 60, 90 and 120 cm above the ground and 4 meters post spacing, binding barbed wire on posts with 1.6 mm diameter wire. Type II had 4-barbed wire of the height of 30, 50, 75 and 110 cm and 4 meters post spacing, hanging barbed wire on posts with split cotter pins. Type III had 3-barbed wire of the height of 40, 70 and 110 cm and 9 meters post spacing using droppers at 3 meters interval. Type IV had 3-barbed wire of the height of 35, 65 and 95 cm and 25 meters post spacing using droppers at 5 meters interval. Wire tension was 20 kgf (196 N) for type I and II by hand, and 100 kgf for type III and IV by using strainers. In the fence maintenance, type I and II were left in the winter, but type III and IV were laid down all wire with droppers before winter and raised them in spring. The construction costs and maintenance costs of four types fences were compared for three years. The cattle escaping through the fences was not found. The maximum snow depth was observed 148 cm in Feb. of 1986, 90 cm in Feb. of 1987 and 100 cm in Feb. of 1988, respectively. As the snow settling force attacked barbed wire, the wire was broken or sagged in type I and II, breaking the wire to bind barbed wire and split cotter pins to hang one. In type III and IV, the snow damage was not found because of a lay-down system for all wire with droppers. In view of the comparison of fence costs, the construction costs could be reduced in case of increasing the post spacing and decreasing the numbers of barbed wire, and the maintenance costs could be reduced by layingdown wire with droppers as being no snow damage. Accordingly, it is recommended the lay-down fence like type III or IV in the snowy area. This lay-down fencing system is useful on the fiat pastures but may be difficult to stretch tightly barbed wire on the rolling or sloping pastures because the barbs on barbed wire often are caught on posts.
