An agent-based simulation model to compare different reproductive strategies in cow-calf operations: Technical...

Area of Science:

• Animal Science
• Reproductive Biology
• Agricultural Systems Modeling

Background:

• Optimizing reproductive efficiency is crucial for beef cattle production.
• Different reproductive strategies, including natural mating (NM) and timed artificial insemination (TAI), have varying impacts on herd performance.
• Agent-based modeling offers a powerful tool for simulating complex biological systems and evaluating management strategies.

Purpose of the Study:

• To develop and validate a stochastic, agent-based simulation model for a synthetic Nelore beef cattle population.
• To compare the technical performance of ten different reproductive management scenarios.
• To identify the most effective reproductive strategy for enhancing beef cattle production in Brazil.

Main Methods:

• A stochastic, agent-based simulation model was created and parameterized with data from a Nelore herd in São Paulo, Brazil.
• Ten reproductive scenarios were simulated, including natural mating (NM) only, and various combinations and intervals of timed artificial insemination (TAI) with NM.
• The simulation ran for 5000 days, with outcomes assessed on an animal-by-animal basis after reaching a steady state.

Main Results:

• The scenario with three timed artificial inseminations (TAI) and natural mating (NM) with a 24-day interval (3TAI/24 + NM) produced the highest number of births (279.85 ± 0.47) and heaviest calves at weaning.
• This scenario also achieved the greatest total pregnancy rate (0.91 ± 0.00) and the longest age at culling for cows (3658.88 ± 10.41 days).
• Natural mating (ONM) resulted in the lowest number of births and lightest calves, requiring significantly more days to reach 50% pregnancy.

Conclusions:

• The developed simulation model accurately represents key interactions within a beef cattle herd, offering a cost-effective alternative to physical experiments.
• Reproductive strategies incorporating timed artificial insemination (TAI) with a 24-day interval between inseminations demonstrate superior technical performance.
• The findings provide evidence-based recommendations for optimizing reproductive management in Nelore beef cattle herds.