Genealogical and morphological analysis of Lusitano Purebred horses participating at international Dressage competitions.

The study analyzes the genealogical and physical features of Lusitano Purebred horses who have participated in international dressage competitions, particularly those ranked by the International Equestrian Federation. The researchers were studying for any underlying patterns or trends that may differentiate these horses from others, giving insights into breeding and training trends.

Pedigree Reconstruction and Population Analysis

• The study used a large sample size of 324 Lusitano Purebred horses (LPB) that have participated in international dressage competitions – with 32 of these ranked by the International Equestrian Federation (FEI).
• The pedigree of each horse was painstakingly rebuilt to include a total of 1148 animals. This immense genealogical pool was then divided into groups for analysis:
• Complete Pedigree (CP) incorporated all horses,
• PARTIC was a sub-group featuring animals that had participated in FEI competitions,
• while RANK was a subset of animals specifically ranked by FEI.

Morphological Analysis and Statistical Tests

• Ten physical parameters, obtained during the breeding process, were examined in detail. The factors considered were sex, age, and an interaction between sex and age.
• After applying multivariable analysis to these factors and the morphological parameters, variables showing significant differences were then subjected to further statistical testing, namely Least Square Means and Tukey post-hoc tests.
• The researchers also identified the 10 most influential founding horses for each population group and compared their physical traits against the rest of the pedigrees using independent sample T-Tests.

Findings and Interpretations

• The CP group generally had higher average scores for all physical parameters, with the exception of “Back”, “Croup”, and “Height”. This suggests an evolution in the morphological selection in LPB horses over generations.
• Sexual dimorphism (physical differences between males and females) was observed, with older male horses scoring the highest for most physical parameters. This could suggest a performance advantage for older male LPB horses in dressage competitions or a preference among trainers and breeders for these horses.
• Finally, different founding lines were identified in the RANK population, which indicates differing breeding or selection trends among horses that get ranked by FEI.
• In conclusion, the study suggests that LPB breed standards need to align more closely with the performance parameters that seem to influence ranking and success in dressage competitions. This could help improve genetic progress and competitive performance amongst these horses.