Height at withers data mostly from birth to 36 months of age of 26 Pantanei
ro horses were used to fit Brody, Richards, Gompertz, Logistic, Weibull and
Morgan-Mercer-Flodin nonlinear response functions. Based on measures of av
erage curvature and combined mean square error, the Weibull model was chose
n. The asymptote of this curve, representing the average height at maturity
, was higher for males than females. The maturity index, however, was more
elevated for females than males. There was indication of a negative associa
tion between the maturity index and height at maturity only for females. Th
ese results indicate that females mature earlier. After checking for normal
ity and homogeneity of variances within groups (sex) the analysis investiga
ted sex differences via t-tests. A significant difference was detected only
for height at birth.