Demographic characterization and genetic variability of the Girgentana goat breed by the analysis of genealogical data

Abstract

The aim of this paper is to present an overview of the actual Sicilian Girgentana population structure by the analysis ofgenealogical data. Statistics show that in 1983 the population consisted of 30,000 Girgentana goats; ten years lateralmost 98% of the entire Girgentana population disappeared. The remaining population consists of 461 individuals (134males and 327 females), with 368 living animals. The effective population size is 380 individuals. The inbreeding rate pergeneration was equal to 0.13%. The average estimated inbreeding level within the living male population was equal to0.8% (0-15%); and the average inbreeding level within the living female population was equal to 0.7% (0-31%). Theaverage relationship between males and females estimated on 27,772 possible matings was equal to 0.5% (0-8.7%).The estimated inbreeding level was not high due to the lack of pedigree information. This is resulting in a ratio betweenthe number of founder equivalents (ƒe = 22,94) and the number of absolute founders (ƒa = 93) equal to 25%.

Keywords

• Girgentana goat, Small population, Demographic parameters, Inbreeding