Quantitative analysis of short- and long-distance racing performance in young and adult horses and association analysis with functional candidate genes in Spanish Trotter horses.

This research focused on studying the influence of certain genes on short- and long-distance racing performance in young and adult Spanish Trotter horses. The results revealed significant associations of particular genotypes with racing performance, suggesting genetic factors play a key role in horse athleticism.

Research Methodology

• The researchers chose five genes (MSTN, COX4I2, PDK4, DMRT3, and CKM) to investigate based on their suspected relevance to time per kilometre (TPK) trait seen in Spanish Trotter horses (STHs).
• They analysed 334,516 records of TPK from 5,958 STHs and used these to estimate the estimated breeding values (EBVs) at different age groups (young and adult horses) across a range of distances (1,600-2,700 m).
• This estimation was performed using a random regression model, a statistical tool that allows the fit of a model that can change over time or distance.
• The study stratified the horses into different groups according to age (young and adults) and racing distance (short and long), considering the highest and lowest deregressed EBVs.
• A group of 321 STHs was selected from these strata for SNP genotyping of the target genes.

Results of the Study

• The heritability factor across the different distances ranged from 0.16 to 0.4, indicating a moderate level of genetic influence on racing performance in trotter horses.
• Investigation of the SNP genotyping revealed that young trotters with the GG genotype in the PDK4 gene and the AA genotype in the DMRT3 gene performed best in short-distance races.
• Horses with the AA genotype in the DMRT3 gene and CC genotype in the CKM gene were the best performers in long-distance races.
• Adult trotters with the AA genotype in the DMRT3 gene exhibited better speed and endurance.

Conclusion of the Study

• The researchers concluded that specific genotype patterns in various genes are associated with racing performance in Spanish Trotter horses.
• Notably, the genes PDK4 and DMRT3 were linked with short distance running performance, while genes DMRT3 and CKM were associated with long distance performance.
• The findings underscore the significant contribution of genetics in the sporting performance of horses, potentially guiding future breeding and training strategies.