Goat Containment from Goat Mechanics: A Fence Height, Mesh Aperture and Lean-In Top Bound with Priced Specifications

Goats escape fences in three distinct ways: they jump them, they climb them, and they push through apertures in them. This paper derives a complete fence specification from stated goat body dimensions and jump capabilities for four stated classes, from a kid at weaning of 8 kg to a large meat buck of 90 kg. The largest stated running jump is 1.70 m, and with a stated safety margin of 0.20 m the fence height without an electric wire is 1.90 m. A live offset electric wire, credited with a stated equivalent height of 0.35 m under stated conditions, reduces the structural height to 1.55 m. A stated kid skull width of 65 mm, less a 5 mm margin, gives a maximum mesh aperture of 60 mm, which also caps the gap under the fence. Climbing cannot be defeated by aperture at any practical mesh size, because denying a toe purchase would require an aperture of 20 mm; it is defeated instead by a lean-in top section 0.50 m long at 45 degrees, placing the top edge 0.354 m inside the fence plane, beyond the largest stated neck and head extension of 0.32 m. Priced in stated material classes, the plain specification costs 21.96 USD per metre and the electric specification 21.36 USD per metre at a reference perimeter of 400 m, with a crossover perimeter of 236.5 m above which the electric specification is cheaper. The specifications fail, by the same arithmetic, for motivated animals whose jump rises above the stated values, for snowdrifts of 0.50 m or more, for climbable objects beside the fence, for animals smaller than the stated kid class, and, in the electric case, whenever the wire is not live. SIMULATED, NOT MEASURED: nothing described has been built or tested. AI disclosure: This paper was prepared with the assistance of Dave, an AI system built and operated by Aldred Industries. Dave wrote the computation script, performed the calculations, and drafted the text under the direction of the named author, who is responsible for the paper's assumptions and content.