Four effects related to the establishment of breeding season in production systems were analysed using a bioeconomic simulation model arise from implantation of breeding season in production systems. The effects were: decrease calf's mortality rate (10 to 4%) (effect A); reduction of bulls:cows relation from 1:25 to 1:33 (effect B); increase reproduction of cows (65 to 75%) (effect C); and reduction of herdsman number (effect D). With these effects were five scenery. The rate increase of present net value and brute margin, in relation to scenery without breeding season (scenery one) were respectively 7.64 and 7.68%; 12,91 and 13.84%; 25.36 and 25.25%; and 30.39 and 31.31%. The breeding season implementation provided increase in economical and biological systems efficiency. The reproductive rate growth was the effect with mayor impact in activity. The accumulate effects of breeding season implantation were able to increase gross margin in 31%.
breeding season; beef herd; bioeconomic simulation
