Genetic Variability Trend of Lusitano Horse Breed Reared in Italy.
Authors: Cozzi Maria Cristina, Valiati Paolo, Longeri Maria, Ferreira Carlos, Abreu Ferreira Sofia
Journal: Animals : an open access journal from MDPI
Summary
# Genetic Variability in Italian Lusitano Horses: Encouraging Diversity with Strategic Breeding Cautions The Lusitano breed, traditionally Portuguese but now internationally distributed, requires ongoing genetic monitoring to maintain population health—particularly in secondary breeding populations like Italy's. Researchers analysed 16 microsatellite markers across 384 Italian-bred Lusitanos registered between 1975 and 2019, tracking observed heterozygosity, inbreeding coefficients, and allelic richness across four decade-long periods to identify temporal trends in genetic structure. Encouragingly, observed heterozygosity in unrelated animals increased substantially from 0.594 (1975–1990) to 0.68 (2010–2019), whilst inbreeding coefficients declined from 0.208 to 0.019 over the same timeframe—indicating expanding genetic diversity without evidence of recent population bottlenecks. Despite these positive indicators and a marked 156% increase in registered dams between the 2001–2010 and 2011–2019 cohorts, the concerning concentration of 77.2% of recent foals from just four sires suggests that future breeding decisions warrant careful consideration of sire selection to prevent inadvertent reduction in effective population size. For breed societies, veterinary advisors, and breeding programmes, these findings underline the value of parentage testing and periodic genetic assessment in maintaining breed vitality whilst identifying when management intervention—such as strategic sire rotation or international genetic exchange—becomes necessary.
Read the full abstract on PubMed
Practical Takeaways
- •Genetic diversity in Italian Lusitano populations is improving, but stallion selection remains heavily concentrated—breeders should consider using a broader range of sires to maintain long-term genetic health
- •The dramatic increase in available dams provides an opportunity to reduce inbreeding further; breeding programs should leverage this expanded female population
- •Current data shows no recent population bottleneck, but continued monitoring of sire contributions is essential to prevent future genetic drift
Key Findings
- •Observed heterozygosity increased over time in unrelated Lusitano horses from 0.594 (1975-1990) to 0.68 (2010-2019)
- •Inbreeding coefficient (Fis) decreased significantly from 0.208 (1975-1990) to 0.019 (2010-2019) in unrelated horses
- •Number of dams increased 156% from 2001-2010 to 2011-2019, supporting genetic diversity
- •77.2% of foals in recent years were sired by only four stallions, indicating concentrated sire usage despite improved dam diversity