Table 1.1 Proposed description for age stages of cats and dogs.
Age stage Description

1 (Fetal) Conception to birth - from fertilisation through embryological development to birth

2 (Growth) Growth - from birth until skeletal growth is completed

3 (Adulthood) Young adulthood - active reproductive phase. Until age-related changes affect appearance and/or organ function

6 (Ageing) Advanced adulthood - obvious external signs of ageing and/or evidence of age-related changes affecting the function of at least one major organ system

7 (Senile) Age-related loss of central nervous system function leading to cognitive impairment and/or loss of control over at least one major organ system