Evolution of height at withers in the Chilean horse population

Introduction: Chilean Horse Studbook established in 1921 limits of height at withers as 1.38 to 1.5 m. In 1978 and 2002 limits were refined as 1.38 to 1.48 m (ideal 1.42 m) for males, and 1.36 to 1.46 m (ideal 1.40 m) for females. Currently, different values are observed in the breed. Evolution of height at withers of Chilean horse was analyzed since the definition of its first standard.

Materials And Methods: Height at withers were analyzed in 1,637 adult Chilean horses (1,068 males, 569 females), clasified in three periods: 1 (horses born since 1958 to 1978), 2 (horses born since 1979 to 2002), and 3 (horses born since 2003 to 2016). ANOVA was performed to determine differences between periods and sexes.

Results: Average (± standard deviation) of height at withers in period 1 was 1.426±0.016 m (males 1.43±0.027 m, females 1.422±0.023 m), period 2 was 1.397±0.024 m (males 1.400±0.028 m, females 1.394±0.029 m), and period 3 was 1.397±0.055 m (males 1.399±0.028, females 1.394±0.024). A significant difference was observed for period 1 compared to 2 and 3 (p<0.05), but no difference was observed between periods 2 and 3. A significant difference was observed between sexes (p<0.01). A 2%, 18% and 18%, of males of the periods 1, 2 and 3 presented values below the limit of the period. In females, values below the limit where in a 1%, 26% and 5% in periods 1, 2 and 3. In males, the upper limit of the standard was exceeded in period 1 and 2 by 1% of the horses, and by 1% of females in period 2.

Discussion/Conclusion: Currently, male average height at withers is lower than standard ideal for Chilean horses.

References

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