The sex ratio in farmed American mink (<i>Neovison</i> <i>vison</i>)

Abstract

The aim of the study was to analyse the sex ratio of American mink litters in relation to dam's age, gestation length, and time interval between the first and second mating. The observations were carried out on a mink farm located in northern Poland. The analysis involved litters of 207 females, aged 1 (n = 107) and 2 years (n = 100), which successfully raised all the born kits. The sex of the offspring was identified on weaning. The kits were assigned to groups according to their dam's gestation length, mating date, and first-to-second mating interval. It was found that female kits quantitatively predominated over male offspring. Longer pregnancies, delayed mating time, and greater interval between the first and second mating was accompanied by a higher number of female births in relation to male births.