HERDBOOK ANALYSES OF THE ASTURIANA BEEF-CATTLE BREEDS

Data from 2 Asturiana breeds' herdbooks were analysed to study their g enetic structure. Herds were assigned to 3 levels by the use of herd s ires. Generation intervals averaged 5.3 (Casina) and 5.4 (Carrenana) y r, and for both breeds sires were significantly younger than dams. Det ermination of the important herds shows the contribution of Caso count y (60%) to the total herd appearance of the Casina breed. The overall mean Wright's inbreeding coefficients were 1.2 and 0.2% and the increa ses of inbreeding level per generation were 0.7 and 0.24% for Casina a nd Carrenana, respectively. Those low values of inbreeding increase ca n be partially explained by a relatively low centralization reflecting a high degree of diversity.