Characterization of the global Brown Swiss cattle population structure

Abstract: The global Brown Swiss population was studied to estimate population genetic parameters, measure genetic variation and identify most influential animals. The population was found to have 3.30 mean equivalent complete generations. The mean inbreeding coefficient was 0.77% for the pedigree population. There was, in most cases, periodic and generational increase of mean inbreeding coefficient. Results showed that there was 0.40% increase in inbreeding by equivalent complete generations. Increase in average generation per period was also noted from the study. The pedigree population had 1.1% mean average relatedness. Effective population size for the equivalent complete generations was a mere 125.97, which could be considered as a small size considering the number of individuals in the population under study. There was big variation between average generation intervals for the four parental pathways. The highest average generation interval was seen in the sireson path way, having a value of 8.73. The average generation interval for the whole population, which was 6.53, was also high. The pedigree population had 0.55% mean coancestry between its individuals. The French Brown Swiss subpopulation had the highest mean coancestry among its individuals. The French and the Austrian subpopulations had the highest mean coancestry between their subpopulations. The Italian subpopulation had the highest equivalent complete generation. The lowest genetic distance was recorded between the Italian and the US subpopulation, implying they had the highest genetic similarity. Most of the genetically influential individuals were sires. The highest contributing founder was a sire with 3.22% contribution. The highest contributing dam had 1.75% contribution. The effective number of founders and effective number of ancestors were 141 and 88, respectively.