Volume: 57 Issue: 3
Year: 2026, Page: 379-384, Doi: https://doi.org/10.51966/jvas.2026.57.3.379-384
Received: Feb. 4, 2026 Accepted: April 6, 2026 Published: Sept. 30, 2026
Understanding herd demographic structure is fundamental for evaluating productivity, disease dynamics, and management interventions in dairy systems. This study developed a dynamic production subsystem to represent the progression of female cattle through key physiological and production stages using a system dynamics modelling approach. The subsystem captures transitions from calves to heifers, pregnant heifers, and successive lactations (L1 L4+), incorporating biologically realistic delays for maturation, gestation, calving, and parity progression. The model was formulated using ordinary differential equations and simulated over a 10-year period to assess internal consistency, numerical stability and long term behaviour. Simulation results demonstrated coherent population dynamics with orderly progression through life stages and no biologically unrealistic accumulation in higher parities. Calf and heifer stocks showed expected transient behaviour, while lactation stocks exhibited staggered peaks corresponding to cumulative biological delays and attrition due to culling and mortality. The absence of oscillations and negative stock values indicates numerical stability and preservation of mass balance. The resulting parity-wise herd structure closely reflects patterns observed under stable dairy management conditions. The production subsystem provides a robust demographic foundation for integration with epidemiological and economic models, particularly for production diseases such as mastitis where risk and losses vary by lactation stage. By explicitly representing physiological delays and population turnover, the model enables evaluation of long-term management strategies and their delayed effects on herd structure. This subsystem can be readily extended to support integrated analyses of productivity, disease control, and sustainability in dairy production systems.
Keywords: System dynamics, dairy cattle, herd demography, production subsystem
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© 2026 Nithya et al. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Nithya, G., Kollannur. J.D., Vinodkumar, K., Shyma, V. H., Kaniyamattam, K., & Jameel, A. J. (2026). A system dynamics approach to modelling dairy cattle production structure and herd dynamics Journal of Veterinary and Animal Sciences, 57(3), 379-384