A Comparison of Tooth Eruption and Wear and Dental Cementum Techniques in Age Determination of New Zealand Feral Pigs.

Abstract

This study evaluates dental ageing techniques for feral pigs in northern South I., New Zealand. Ages of pigs were estimated by three techniques: tooth eruption and replacement on criteria calibrated from pen-reared American-bred European wild pigs; tooth eruption, development, and wear calibrated from known-age feral pigs from the study area; and annular growth in cementum of molariform teeth. All age estimations showed strong agreement with each other and with known ages. The eruption and replacement criteria were most useful for ageing pigs less than 30 months old, whereas the other two criteria were more suited to ageing pigs more than 30 months old. All permanent teeth of New Zealand feral pigs erupted 1-2 months earlier than in European and Malayan wild pigs, and permanent premolars erupted up to 4 months earlier than in Japanese wild pigs. Earlier eruption may reflect early onset of maturity in New Zealand pigs. The clarity of annuli observed varied between animals, but generally increased with age. Pigs from unforested habitat had a higher percentage of clearly defined annuli than those from forested habitat. This may be explained by a climatic or dietary factor.