Association of antler asymmetry with hoof disease in elk

Abstract

Treponeme-associated hoof disease (TAHD) is an emergent disease of elk (Cervus canadensis) in the Pacific West of the United States. Although lesions are usually restricted to the feet, anecdotal reports suggested increased prevalence of abnormal antlers in affected elk. We used hunter harvest reports for 1,688 adult male elk harvested in southwestern Washington, USA, during 2016-2018, to evaluate anecdotal reports. We used Akaike's Information Criterion to compare 18 logistic regression models describing the prevalence of asymmetrical antlers, indicated by unequal antler point counts.Our leading model (84% of model weight) described additive effects of TAHD (odds ratio = 1.91; 95% CI = [1.49, 2.44]) and maximum number of antler points. Confidence intervals overlapped zero for all other parameters, which described ecotypic, geographic, and age-related effects. Effects of physical injury on antler development have been described elsewhere; however, injuries leading to instances of antler deformity do not have population-level management implications. In contrast, we describe effects of a transmissible disease that was reported by hunters in >35% of adult male elk and was associated with an increase of ≥16 percentage points in the prevalence of gross asymmetry. Unequal point counts are quite

Community Science Strategies Reveal Distributional Patterns of Treponeme-Associated Hoof Disease in Washington Elk (Cervus canadensis)

“…Instead, observations of abnormal hooves by hunters provided a useful alternative as apparent TAHD cases. As discussed by Wild et al [30], the accuracy of hunter observations was highly specific (96%) for identifying uninfected hooves and hooves with severe lesions (92%) when compared to visual examination by experts (WDFW, Unpubl. data).…”

“…The second CS surveillance strategy relied upon reports from hunters and was previously described by Wild et al [30]. Briefly, WDFW collected data using mandatory hunter reports to assess whether harvested elk had hoof abnormalities.…”

“…1 Unpublished data, Washington Department of Fish and Wildlife (WDFW). Sensitivity of Hunter Reports varied by lesion severity and is with respect to gross observation by an expert observer; Wild, Sargeant et al [30]. 2 Sensitivity from a similar technique in bovine digital dermatitis model by Krull et al [31].…”

Associations between hair trace mineral concentrations and the occurrence of treponeme-associated hoof disease in elk (Cervus canadensis)

“…Rather than omitting or misattributing spatial properties of data, we used available information to conservatively reclassify cases into a broad scale longitudinal category variable because of the importance of longitude in mineral concentrations [44]. This variable also corresponded with elk ecotype from other investigations [45] considering known patterns of Roosevelt elk generally being found along the Pacific Northwest coast, while Rocky Mountain elk can be found east of the Pacific crest and into Idaho [46,47]. For clarity, we named this variable "Longitude" to represent its use as a crude east-west dichotomy rather than directly attributing it to intrinsic biologic difference in ecotype, although this cannot be excluded.…”

Systemic epigenome-wide association study of elk treponeme-associated hoof disease

“…Minor lesions have been detected in elk as young as 3 months of age and severe lesions occur in 9 month old elk 2 . Although TAHD lesions are generally limited to the feet, increased antler asymmetry has been associated with TAHD in male elk 5 .…”