Efficacy of secondary electric fences at preventing direct contact among white-tailed deer
Free-ranging and captive cervid herds are at risk for chronic wasting disease transmission from direct contacts at fences, so we explored the use of a secondary electric fence to prevent contacts in white-tailed deer ( Odocoileus virginianus ). Using a captive herd of white-tailed deer in Pennsylvania, USA, we tested the efficacy of two electric fence designs (one three-strand and one six-strand) constructed along separate primary fence lines (each composed of 20 m of chain link and 20 m of woven wire fencing) dividing paddocks of captive deer. From June to November 2019, we conducted three trials of variable lengths to assess how season, age, and sex impacted behavior and motivation of deer to breach the electric fence. When no electric fence was in place, we observed 117 direct contacts through woven wire and chain link fences. With the electric fences in place, we observed electric fence breaches (which led to direct contact between deer) by weaned fawns (37 breaches, 4 direct contacts) and males in the mid- and late-rut (2 breaches, 1 direct contact). The majority of breaches occurred across the three-strand-fence. Our results suggest that no style of primary fence alone is sufficient to prevent direct contacts and that the addition of a secondary, properly designed electric fence constructed along the primary fence of captive white-tailed deer facilities could prevent direct contact between captive and free-ranging deer.