Sows' longevity -a case study of a native breed. The aim of the study was to assess the length of use of Z otnicka Spotted sows, which are covered by the National Programme for the Conservation of Genetic Resources. The research was conducted on 3,585 sows removed from herds between 2002 and 2017. On average, Z otnicka Spotted sows were removed from the herd when they were 1,112 days old and had farrowed 3.88 times. The research proved statistically signi cant dependencies between sows'

more »

... al traits and the parameters determining their longevity. The research ndings showed that the length of use of sows depended on the number of piglets in the rst and last litter as well as the number of piglets reared up to the 21st day per litter. The study also includes data on the percentage of Z otnicka Spotted sows removed (%) from herds during the period under study and the percentage share of primiparous sows introduced into herds. During the research period the values of both indicators uctuated considerably, which indicated the unstable size of the population. These dependencies were closely related with the RDP 2007-2013 and 2014-2020 and the amount of subsidies allocated to native breeds. The length of use of sows is a very complex feature. It is of great economic importance and closely related with the pro tability of pig production. Therefore, although breeders received subsidies to native breed of sows, the downturn in the pig market caused instability of the pig population.