Analysis of diversity and population structure in the Lipizzan horse breed based on pedigree information

Abstract

The pedigrees of 565 Lipizzan horses from eight European studs were traced back to the individuals considered as the founding population of the breed. The length of pedigrees was up to 32 generations, with an average of 15.2 complete generations. Average inbreeding coefficients varied from 8.6 to 14.4% between studs, with an overall mean of 10.8%. Increase in inbreeding was relatively small in the last generation. Other measures of genetic variability based on contributions of founders or important ancestors were also calculated, leading to partly different conclusions about the variability of the population at stud level. Average coancestries between studs showed that the two Romanian studs were most similar but also that the Austrian, Slovenian and Italian studs formed a cluster of genetically similar individuals. The pedigrees were also used to calculate gene proportions of founder breeds and individual founders. About 52% of the current genes are of Spanish or Italian origin, 21% Arabian, 8% Fredriksborg, 4% Kladruby, 3% English and 2% Shagya-Arab. The most important founder individual was Toscanello Hedera, followed by Neapolitano, one of the founders of the classical stallion lines, each contributing more than 6% of the current gene pool.