Genetic structure of three Croatian horse breeds: implications for their conservation strategy

Abstract

The genetic variability for a sample of 107 animals from three autochthonous Croatian horse breeds was estimated using 20 microsatellites. The average number of alleles per locus (6.3) and proportion of heterozygosity (0.732) indicated a moderate variability. The expected heterozygosity was similar among all breeds and ranged between 0.724 in the Posavina horse, and 0.737 in the Croatian Coldblood and Murinsulaner horse. The inbreeding coefficient F IS was low and non-significant over the three populations. The genetic differentiation among the three populations was low (F ST =0.026), suggesting that only 2.6% of the total genetic variability was due to differences between the breeds, and 97% to individual differences. The results of pairwise genetic differentiation suggest that the Posavina horse and the Croatian Coldblood were the most closely related populations (F ST =0.016). These results are confirmed by Nei's genetic distances with the highest value observed between the Posavina horse and the Murinsulaner (0.082) and the lowest between the Posavina horse and the Croatian Coldblood (0.044). An assignment test correctly assigned 82% of individuals to the correct breed. Strategies for preserving the original native genes in the Croatian native horse breeds should be considered in order to prevent these breeds from becoming extinct and include them in the future breeding programmes.

Hematological and Serum Biochemical Reference Values for the Posavina and Croatian Coldblood Horse Breeds

“…The Studbook for the Posavina horse breed was closed in 2004 [4], while creation of the Studbook for Croatian Coldbloods still proceeded until its formal closure in 2008 [5]. Although considered as different breeds, Ivankovic et al [6] found, based on mitochondrial D-loop sequence variation, that the Posavina and the Croatian Coldblood horses were the most closely related populations. Furthermore, using microsatellite markers, Galov et al [7] did not observe genetic differentiation between these two breeds.…”

“…In the same year, the number of Croatian Colblood horses was 6304, with 902 animals in the area of Sisak-Moslavina County [8]. In Europe, the coldblood autochthonous horse breeds have become endangered, as they lost their traditional use value as working animals [6]. However, fl oodplain areas along the Sava River and its tributaries are a rare eco-system with preserved traditional way of horse breeding and herding in general [9].…”

Genetic structure and admixture between the Posavina and Croatian Coldblood in contrast to Lipizzan horse from Croatia

“…There are no records that the Lipizzan has had a substantial influence on the Posavina or Croatian Coldblood, although evident admixture of 13% of animals both from the Posavina and Croatian Coldblood with the Lipizzan (Figure 2) indicates that crossing with the Lipizzan does occur sporadically. Ivanković et al (2009) investigated genetic structure of the Posavina, Croatian Coldblood, and Murinsulaner breeds using population genetic analyses based on genetic distances and a prior assignment of samples to breeds. They found low levels of genetic differentiation among the breeds, noticeably lower than among some other ones and showed that these three breeds did not form defined clusters.…”

“…Ivanković et al (2009) investigated genetic structure of the Posavina and Croatian Coldblood, in comparison with the Murinsulaner horse being the third Croatian autochthonous breed and found that the Posavina and the Croatian Coldblood were the most closely related populations. Genetic diversity and differentiation of Lipizzan horses from seven European countries including Croatia were revealed by genetic distance and principal component analysis (Achmann et al, 2004).…”

Mitochondrial D-loop sequence variation among autochthonous horse breeds in Croatia

“…These breeds were bred in geographically narrow areas, using different breeding and selection approaches. Posavina horse was formed according to earlier studies by introducing the Arab genome, the Croatian Coldblood was under a significant influence of the English Thoroughbred and Belgian Coldblood, while Murinsulaner horse was affected by the Noric and Percheron breeds (Romić, 1975;Ivanković and Caput, 2004a). The majority of the Posavina horse population is located in the territory of Croatia, while a minor part can be found in Slovenia and Bosnia and Herzegovina.…”