Correlation between l-lactate and glucose concentrations and body condition score in healthy horses and ponies

Blood l-lactate and glucose concentrations were higher in ponies with gastrointestinal disease than in horses, possibly because of differences in body condition (BC).

To investigate whether l-lactate and glucose concentrations correlate with BC and differ between healthy horses and ponies.

Systemically healthy client-owned ponies (n = 101) and horses (n = 51).

Prospective observational study. Breed, weight, height, and subjective and objective measures of BC were recorded and l-lactate and glucose concentrations were measured. Correlations between l-lactate and glucose concentrations and BC were established. The association between l-lactate concentrations, equid type (pony or horse), BC, age, and glucose concentrations was investigated using a multivariable model.

Weak but significant (P = .001) negative correlations were detected between l-lactate concentration and average BC score (r = -0.29), heart girth:height ratio (r = -0.27), and age (r = -0.27). Glucose concentrations were significantly (P < .001) positively correlated with neck length:heart girth ratio (r = 0.37) and heart girth:height ratio (r = 0.31). l-lactate and glucose concentrations were weakly correlated (r = 0.15; P = .04). In the final multivariable model, age (-0.02 ± 0.006; P = .001) and heart girth:height ratio (-1.74 ± 0.53; P = .001) were significantly associated with the natural logarithm of l-lactate concentration (Lnl-Lactate). This represents a 2% decrease in l-lactate concentration per year increase in age and 10% decrease in l-lactate concentration per 0.06 unit increase in heart girth:height ratio.

In healthy horses and ponies, age and BC significantly influence l-lactate concentrations.