Bronson R T
Am J Vet Res. 1982 Nov;43(11):2057-9.
A retrospective study of necropsy data for 2,002 dogs showed that the mean age at death of neutered dogs of both sexes exceeded that of intact dogs, but the differences were not significant. A wide variation in mean age at death of 56 breeds and cross breeds, 3.0 to 9.9 years, was found. This variation was not correlated with mean breed body weight. An attempt was made to explain the variability by finding diseases to which dogs of the short-lived breeds were particularly susceptible. This was not possible in general, since the samples of each breed were small and the total number of diseases from which they died so large. Dogs of long-lived breeds died of diseases appropriate to their age, particularly cancer, 39% of the sample. In the sample as a whole, cancer accounted for 20% of deaths at 5 years and increased to and remained between 40% and 50% from 10 to 16 years of age.
一项对2002只狗的尸检数据进行的回顾性研究表明，绝育的雌雄犬的平均死亡年龄超过了未绝育犬，但差异并不显著。研究发现，56个品种和杂交品种的平均死亡年龄差异很大，从3.0岁到9.9岁不等。这种差异与品种的平均体重无关。研究试图通过找出短寿命品种的狗特别易患的疾病来解释这种变异性。但总体而言这是不可能的，因为每个品种的样本量都很小，而它们死亡所患疾病的总数又如此之多。长寿品种的狗死于与其年龄相符的疾病，尤其是癌症，占样本的39%。在整个样本中，癌症在5岁时占死亡原因的20%，从10岁到16岁，这一比例升至40%至50%之间并保持在该区间。
