Accuracy of moose age determinations from canine and incisor cementum annuli

Abstract

We sent 76 canines and 77 incisors (I1) from 84 known-age moose (Alces alces) !2 years old sampled from near Fairbanks, Alaska, USA (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)) to Matson's Laboratory (Milltown, MT) to test G. Matson's accuracy rate in estimating moose ages. To estimate ages, G. Matson counted annuli in the cementum of root tips using a Giemsa-staining technique and assumed a birth date of 1 June. We originally radiocollared moose at 9 months of age, and we extracted teeth upon death. Estimated moose ages averaged 7.0 years using canines and 6.9 using I1 teeth (range ¼ 2-16 year), and known ages of each sample averaged 7.1 years. The accuracy rate among 76 canines was 74% and improved to 95% when ignoring errors within 1 year of the known age; comparative results among 77 I1 teeth were 66% and 94%. By far the most frequent error was a 1-year underestimate in age, particularly for moose that died in July and August, which included the seasonal transition period associated with completing peripheral annuli formation. After controlling for À1-year errors associated with the seasonal transition period, we found evidence for errors accumulating with age. We found no significant difference in accuracy based on which tooth was sectioned. However, G. Matson observed more individually distinct annuli and regular deposition patterns in canines, compared with incisors. Thus, we recommend the more easily extracted canine for estimating moose age. Ó 2015 The Wildlife Society.

Lifetime, known‐age moose reproduction in a nutritionally stressed population

“…In previous studies, age‐specific reproductive rates were based mostly or entirely on approximate ages based largely on counts of cementum annuli in teeth (Sæther and Haagenrud , Gasaway et al , Heard et al , Ericsson et al , Ruprecht et al ). Despite relatively large teeth in moose, counting cementum annuli can be problematic and subjective because of difficulties in distinguishing distinct annuli (Cumming and Evans , Rolandsen et al , Boertje et al ). Cementum annuli counts in moose studies have overestimated and underestimated actual ages (Gasaway et al , Rolandsen et al , Boertje et al ).…”

“…Despite relatively large teeth in moose, counting cementum annuli can be problematic and subjective because of difficulties in distinguishing distinct annuli (Cumming and Evans , Rolandsen et al , Boertje et al ). Cementum annuli counts in moose studies have overestimated and underestimated actual ages (Gasaway et al , Rolandsen et al , Boertje et al ). Counting errors accumulated with age and a small percentage of counts produced errors of several years, even when using the best staining techniques available and the most experienced laboratory personnel (Boertje et al ).…”

“…Cementum annuli counts in moose studies have overestimated and underestimated actual ages (Gasaway et al , Rolandsen et al , Boertje et al ). Counting errors accumulated with age and a small percentage of counts produced errors of several years, even when using the best staining techniques available and the most experienced laboratory personnel (Boertje et al ).…”

Lifetime Sex‐Specific Moose Mortality During an Intentional Population Reduction

“…and ). We caution that differences in aging techniques among moose studies makes comparisons problematic unless correction factors to true age are applied or young, known‐age cohorts are followed through life (Gasaway et al , Rolandsen et al , Boertje et al , Young and Boertje ).…”

Peer Review #1 of "High prevalence of Lynx rufus gammaherpesvirus 1 in wild Vermont bobcats (v0.1)"

“…city or town) was provided by the Vermont Fish and Wildlife Department. Age of individual bobcats was estimated from a species-specific standardized aging model based on the number of cementum annuli observed in Giemsa-stained histological sections of a lower canine tooth, as performed by Matson's Laboratory (Manhattan, MT) using methodology described previously (Boertje et al 2015 Manuscript to be reviewed and collection location data were included in this study. Of the 64 samples meeting that criteria, 48.4% were derived from bobcats harvested by licensed trappers, 37.50% were derived from bobcats harvested by licensed hunters, 12.5% were collected from dead bobcats after motor vehicle collisions, and 1.6% had unknown provenance, according to the Vermont Fish and Wildlife Department.…”