title: Age determination in dogs using ocular light reflection, dental abrasion and tartar.
abstract: OBJECTIVE
  The knowledge of an animal's age is important for disease probability, prognoses, or epidemiological questions, but unfortunately, it is often unknown for dogs in animal shelters. A simple estimating procedure is preferable being quick and easy to perform, even for non-veterinarians.
  
  
  METHODS
  In 295 dogs the dimension of light reflection (diameter in millimetres), visible on the posterior lens capsule using a penlight, the grade of dental abrasion and dental tartar were documented photographically and the exact weight and age in days were obtained. These photographs were evaluated blinded. The dogs were divided randomly into two groups. The first group was used to establish a model for age determination using linear and logistic regression models considering the documented parameters, which was then validated with the data of the second group.
  
  
  RESULTS
  The size of ocular light reflection and age correlated significantly (r = 0.781; p < 0.001; sy,x = 2.45 years [SD of y for given x]). The linear regression model gave the final equation: Estimated age [months] = 13.954 + 33.400 × lens reflection [mm] + 8.406 × dental abrasion [grade] + 8.871 × tartar [grade] with a standard error of estimation of 2.26 years.
  
  
  CONCLUSIONS
  Age determination, even based on three parameters results in a large standard deviation making age estimation in dogs very crude.
authors.affiliation: Kerstin Gesierich, Tierklinik Stommeln, Nettegasse 122, 50259 Pulheim, Germany, Email: k.gesierich@tierklinik-stommeln.de.
authors.forename: K
authors.initials: K
authors.lastname: Gesierich
authors.forename: K
authors.initials: K
authors.lastname: Failing
authors.forename: R
authors.initials: R
authors.lastname: Neiger
mesh_terms: D000366:Age Determination by Teeth / Q000662:veterinary*; D000827:Animal Welfare; D000818:Animals; D003728:Dental Calculus / Q000662:veterinary*; D004285:Dogs / Q000502:physiology*; D005260:Female; D008027:Light; D008297:Male; D012044:Regression Analysis; D014070:Tooth / Q000502:physiology*; D014072:Tooth Abrasion / Q000662:veterinary*
keywords: Eye lens; animal adoption; animal shelter; dental age