engleski

Comparison of different methods for age estimation in roe deer (Capreolus capreolus) – preliminary study

Context: Roe deer (Capreolus capreolus) are a small mammal species from the Cervidae family. Their accurate age estimation plays an important part in game management and, therefore several methods have been developed for this purpose. However, variations between methods can cause errors in age estimation that will also reflect the selection and estimation of trophy values in different age categories. The counting of cementum annuli is considered as the gold standard, however, this method is invasive and time consuming. Aims: To evaluate precision of age estimation obtained by different methods with counting of cementum annuli. Methods: In this study, ten archived roe buck skulls of unknown age with hemi-mandibles were collected. All animals originated from Medvednica Nature Park. For each animal, age was estimated based on six methods. These include ; counting of cementum annuli on decalcified tooth sections stained with Harris’s haematoxylin and on dry tooth sections, inclination of incisors, the ratio between premolar and molar heights to pedicle diameter, the ratio between height of the second molar and pedicle diameter, and the ratio of height of all teeth and pedicle diameters. The counting of cementum annuli on decalcified teeth is considered as the gold standard. The proportion of correct estimation was calculated and a Bland-Altman plot was used to analyse the agreement between two different methods. Key results: According to the counting of cementum annuli on decalcified tooth sections, 5 animals were three years old, four were four years old and one was five years old. In the three years age category, the highest proportion of correct results was obtained by M2 height and pedicle diameter ratio and height of all teeth and pedicle diameter ratio (both 60%). In the category of 4-5 years, the highest proportion of correct results was obtained by M2 height and pedicle diameter ratio (60%). In general, all methods, except for the count of cementum annuli on the dry section of the tooth (bias 0.2), tended to increase with regard to the estimated age of the animal (bias from -0.35 to -1). Conclusion: The majority of methods tended to increase the age of the animal (from 0.5 to maximal 2 years). Due to individual differences larger sample size is required to provide more accurate conclusions.

Roe deer, Medvednica, males, age estimation, cementum annuli, different methods, Bland-Altman analysis

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