The population structure of the registered Tabapuã cattle in Brazil was described. Descriptive statistics of the distribution of the number of progeny, the generation interval, F-statistics, effective number of founders, ancestors, reminiscent genomes and effective population size were estimated using pedigree records from registered animals from 1971 to 1998. In the last period studied (1994-1998), 37,778 animals, 18,736 males and 19,042 females from 136 breeders were registered. The generations intervals calculated in each of the four periods 1979-1983, 1984-1988, 1989-1993 and 1994-1998 were, respectively, 6.26, 7.18, 7.68 and 7.56 yr for parent-progeny and 6.18, 6.43, 6.99 and 7.27 yr for parent to parent. The effective size of the population, founders, ancestors and reminiscent genomes in each of these periods were respectively: 378, 218, 213 and 181; 131, 254, 202 and 163; 73, 150, 119 and 94; 55, 112, 78 and 61.
Cattle; Tabapuã; population structure; generation interval; effective size; inbreeding coefficient
