Equid population dynamics in Mexico over five decades: Divergence between national census records and FAOSTAT estimates

Equid populations are widely used to inform animal health, welfare, and rural development strategies, yet their interpretation depends on how animals are counted, classified, and reported. Using a repeated cross-sectional analysis of national census records, this study examined long-term changes in Mexico's equid population and evaluated the consistency between national Agricultural Census records and FAOSTAT livestock statistics. Data for horses, donkeys, and mules were obtained from the Mexican Agricultural Censuses of 1970, 1991, 2007, and 2022, accounting for changes in how equids and their working functions were recorded over time. The total equid population recorded within Mexican Agricultural Production Units - which does not represent Mexico's overall equid population - declined from 6.82 million animals in 1970 to 1.60 million in 2022, a reduction of 76.5%. Donkeys showed the greatest decline (90.1%), followed by mules (84.1%) and horses (62.0%). In contrast, the census-recorded working-equid population increased by 37.1% between 2007 and 2022, driven predominantly by a 73.0% increase in working horses. Comparison with FAOSTAT revealed a progressively widening discrepancy: the FAOSTAT-to-census ratio increased from 1.82 in 1970 to 8.11 in 2022, with FAOSTAT indicating a 4.5% increase over the same period and observations shifting from official (1970) to estimated (1991, 2007) and imputed (2022). These findings demonstrate a major long-term transformation of Mexico's equid population while also showing that equids remain functionally important within contemporary agricultural systems, particularly through the increasing contribution of working horses. The marked divergence between national census records and FAOSTAT further highlights the importance of considering census definitions, functional classifications, statistical status, and data provenance when equid population estimates are used for research, veterinary planning, animal-welfare interventions, or public policy.