An endangered horse breed can be conserved by using optimum contribution selection and preselection of stallions

The Jutland Horse is an original Danish horse breed and is regarded as Denmark’s national draft horse. It was previously used as a draught horse in the farming industry. The studbook dates back to 1881. After the World War II, the number of horses strongly decreased. Today the breed has around 100 breeding mares and 65 foals are born every year (Szekeres et al., 2016). Thus, as in other endangered breeds, the breed struggles to increase or at least maintain the number of breeding animals. A loss of such a local breed will mean a loss of cultural value (Meuwissen, 2009: Woolliams et al., 2005). In the 80s, the breed struggled with inbreeding related problems due to heavy use of few stallions. Since then, the breed organization of the Jutland Horse succeeded in increasing the number of horses. Because many young stallions (colts) are slaughtered before they reach maturity, the number of approved stallions each year is still low, facing the risk of a high rate of inbreeding. To maximize the effective population size, the optimal strategy is to have equal numbers of breeding females and males (Fernàndez et al., 2011). Thus, to maintain the Jutland Horse breed in the long term it is of high importance to increase the number of breeding sires. In order to increase the number of breeding sires, the breeding association for the Jutland Horse initiated in 2016 a project aiming at securing a larger number of stallions to be available for breeding, and furthermore increase the use of stallions having the lowest relationship to the breed in respectable of their conformation score. The aim of this study was to provide knowledge to serve as a basis for a conservation plan for the Jutland Horse in which sires were selected in two stages.