The dog has often served as a model animal for humans in scientific studies. This is due to the fact that dogs are susceptible to a wide range of diseases which also affect humans. One example is cancer, a condition that affects dogs as well as owners. Neoplastic diseases account for 18-23 % of all deaths in dogs (Bonnet et al., 2005 and Jagielski et al., 2002). Mammary tumor, or tumor of the breast, is the most common tumor form in intact dogs and women (Im et al., 2013). Mammary tumors originate in the udder, and are classified according to their histological characteristics.

Most of the beef production in Sweden has been integrated with milk production. Since the 1990:s, the number of dairy cows has decreased. A specialised beef production has developed in purpose to compensate for this decrease. The consumption of beef have increased in the last decade, but the Swedish production has no followed this trend. In 2004, the percentage of beef self-sufficiency in Sweden was 60 %.