Effect of reduced age at first calving and an increased weaning rate on CO2 equivalent emissions in a cow-calf system

The objective of this study was to evaluate the impact of using technology to reduce the age at first calving (AFC; from 48 to 24 months) and increase the weaning rate (WR; from 60% to 80%) in beef herds. The need for pasture area (hectares) and the CO2 equivalent emissions (CO2eq.) of animals present in the production system were analyzed. Data from a livestock breeding system were used to produce 400 male calves per year: System 1) using reproductive biotechnology (fixed-time artificial insemination [FTAI] and System 2) without the use of reproductive biotechnology (only natural mating). System 1, which used reproductive biotechnology (FTAI; composed of 1,540 AU of animals in 1,540 hectares), presented a lower AFC (24 months), a higher WR (80%), and lower CO2eq. emissions per year (2,311.3 tons). System 2, which did not employ reproductive technology (composed of 2,475 AU [450 kg of animals] on 2,475 hectares), had the highest AFC (48 months) and lowest WR (60%) and emitted 3,714.5 tons of CO2eq. per year. The reduction in CO2eq. emissions per year was 1,403.3 tons in the system that used reproductive biotechnology, corresponding to gains of US$ 135,920.42 (US$ 96.86 per ton of CO2eq.). It is estimated that the adoption of the FTAI increases the reproductive efficiency of a cow-calf operation system, which can produce the same number of male calves (400) on 935 fewer hectares of pasture (-37.3%) and with a reduction of 1,403.3 tons of CO2eq. produced per year.