The relationship between the welfare quality and stress index in working and breeding horses

Abstract

The aim of this observational study was to investigate if a relationship exists between the calculated overall individual welfare score (as an indicator of the welfare quality) and the neutrophil:lymphocyte (N:L) ratio (as a stress indicator) in working (draught) and reproduction horses (breeding stallions and broodmares), in two different seasons. The welfare of the horses was assessed by a protocol which included health and behavioural parameters. An individual welfare score was computed, the total and differential WBC count was established and the N:L ratio was calculated for each of the 1482 assessed horses. Using all these parameters, comparisons were made between the horse categories (working horses, breeding stallions, broodmares) in two assessment seasons. Finally, the relationship between the individual welfare score and the N:L ratio was studied in light of the significant correlations found. The highest frequency of health problems was recorded in working horses. The human-animal relationship did not present significant differences between the horse categories. The individual welfare scores were significantly lower (P<0.05) in the working than in the breeding animals, in both assessment seasons. The N:L ratio was significantly higher (P<0.05) in the working horses than in those kept for reproduction. The season had no significant influence (P>0.05) on the investigated parameters. All the significant correlations found between the N:L ratio and the individual welfare score were negative. The results obtained indicate poor welfare in the working horses, comparing with the breeding animals. The findings of our study confirmed that the N:L ratio increases in horses with a poor welfare state. The multiple correlations of the N:L ratio with the individual welfare scores of the assessed horses emphasised the efficiency of this parameter in identifying the acute and chronic stress conditions in the living environment of the animals.