Molecular, genealogical and morphometric characterisation of the Pallaresa, a Pyrenean relic cattle breed: Insights for conservation

The Pallaresa cattle breed is a native population of beef cattle found in the western regions of the Catalan Pyrenees (Spain). Since the second half of the twentieth century, population size decreased dramatically in favour of the Bruna dels Pirineus breed. At the present time, it is classified as a relic breed on the brink of extinction by the FAO, as only 22 breeding animals remain alive (2 bulls and 20 cows). Its importance as genetic and cultural heritage and its contribution in maintaining the landscape and ecosystem, as well as its unquestionable interest as a tourist attraction, make it an irreplaceable element in this area. In this paper, we present the breed characterisation of the population at the molecular, genealogical and morphological levels, and the comparison and phylogenetic relationships with other local breeds, in order to contribute to the characterisation of this prominent genetic resource. Genealogical analyses showed that the Pallaresa population is highly inbred. The mean inbreeding for both the whole pedigree and the living population was 18.93% and 25.71%, respectively. A set of 15 microsatellites were typed on the available Pallaresa individuals to ascertain the genetic variability of the breed at the molecular level and to allow a direct comparison with a set of previously studied 19 local cattle breeds from Spain, Portugal and France. The average number of alleles per locus for the Pallaresa breed (4.3) was the lowest of the analysed breeds and the within-population genetic identity, assessed using molecular coancestry, the highest (0.437). The Pallaresa population showed high levels of differentiation from the other analysed breeds. The lowest kinship distance was assessed for the pairs formed with the Bruna dels Pirineus and Salers breeds (0.417±0.010 and 0.427±0.011, respectively). STRUCTURE analysis showed that most Pallaresa individuals were assigned to one distinct cluster, showing that the breed gathers a unique genetic background. Despite its dramatic population scenario, the Pallaresa breed still preserves moderate levels of genetic diversity. The results obtained from the current study can contribute to design appropriate conservation strategies to prevent its extinction in the near future. The implementation of a mating programme involving Pallaresa bulls and Bruna dels Pirineus cows selected according to genetic and morphological closeness to the Pallaresa breed is suggested to prevent the genetic impoverishment of the population.