Sustainable animal breeding in a local cattle breed: a genomic strategy to redefine Reggiana HerdBook standards and breeding goals.

Reggiana is an Italian autochthonous cattle breed, mainly reared in the Emilia Romagna region. At present, a total of about 2800 Reggiana cows, distributed in about 100 farms, are registered to its breed Herd Book. Nowadays, almost all the milk produced by the Reggiana breed is processed into mono-breed Protected Designation of Origin (PDO) Parmigiano-Reggiano cheese that is labelled with the brand name ‘Vacche Rosse’ (according to the typical red coat colour – fromentino – of the breed). This cheese is marketed at a higher price than those of undifferentiated origin. Phenotypic selection in the Reggiana breed has been applied over the last decades to maintain the breed standard defined in the Herd Book (e.g. solid fromentino coat colour, pink or pale muzzle, medium-tall stature, dual-purpose conformation, absence of morphological defects), but a few Reggiana animals do not completely match the breed standard phenotypes. In this study, we defined a strategy to design a sustainable breeding and conservation programme of the Reggiana population, by considering both phenotypic and genetic data. About 70% of the whole Reggiana breed population was genotyped with the GeneSeek GGP Bovine 150k SNP chip. The allele and genotype frequencies and distribution of single nucleotide polymorphism (SNP) markers involved or associated with phenotypic exterior (coat colour and muzzle), morphological traits (e.g. stature and morphological defects), and the presence of deleterious alleles derived from other cattle breeds were analysed. Based on obtained results, information on the genotype at the Extension locus/melanocortin 1 receptor (MC1R) gene has been included in the Reggiana Herd Book as part of the breed standard. Other DNA markers could be included or could be used to cull some animals carrying unwanted alleles/defects or to design appropriate strategies for their effective eradication from the population. These strategies might be integrated in optimum contribution selection plans that would also carefully evaluate the potential loss of genetic variability and effective population size of the breed. This strategy can be useful to design further refine a genomic-driven sustainable breeding and conservation program of Reggiana cattle that is also linked to the genetic authentication of its mono-breed Parmigiano Reggiano cheese. Acknowledgements The research was funded by the PSRN Dual Breeding and Dual Breeding 2.