[en] The results of the flat races organized in Algeria from 1995 to 2007 by the Algerian Horse Racing Society were used to estimate non-genetic parameters of racing performances of Thoroughbred horses. Performances were assessed through two earnings traits (the logarithm of annual virtual earnings: LAEV and the logarithm of average annual virtual earnings per start: LAEV/S) and a normalized ranking (PERF). The phenotypic correlations between these traits were calculated, in order to deduce what is common and what is specific to each measure. The environment factors that were investigated are age (3 to 8 years and older), sex (male or female), year of race (1995 to 2007) and the interactions between these factors. The General Linear Model (GLM) procedure from SAS software was used to identify and quantify the non-genetic factors affecting racing performances. The results showed significantly high positive correlations (p<0.001) between the three traits, hence considered as accounting for similar aptitudes. The effects of age (with a plateau between 4 and 5 years) and year (with an increasing trend for more recent years) turned out to be significant (p<0.001) for the three traits, the sex effect was only significant for the PERF trait (with better performances for males than females) and an interaction between the age and year of the performance was the only significant interaction (p<0.05) for the LAEV trait. The significant effects of these non-genetic factors indicate the need to adjust the earnings and ranks in the context of a program for genetic improvement of Thoroughbred horses in Algeria.
