Influence of some environmental factors on growth characteristics of brasileiro de hipismo horses

Abstract

Height at withers (H), weight (W) and chest girth (Cg) data on Brasileiro de hipismo horses born from 1980 to 1985 in Pioneiro haras located in Brasília, DF, Brazil, were studied. The effects of sex, year and season of birth, season x year interaction, age and height of dam were studied on these traits examined at birth (HB, WB and CgB), six (H6, W6 and Cg6) and twelve months of age (H12, W12 and Cg12). Least squares analyses of variance showed that year of birth had significant effect on most of the variables studied but no significant influence (P > 0.05) on H12, Cg6 and Cg12. Sex influenced significantly (P < 0.05) only H12, while year x season interaction had influenced (P < 0.05) on W12. Age of dam had linear and quadratic effect on HN, H6, W6, W12 (P < 0.01), WN and CgN (P < 0.05). The height of dam had linear and quadratic effect (P < 0.01) on HN and a linear effect (P < 0.05) on H6, H12 and WN. The results showed that the responses correlated in subsequent ages were very high when selecting for measurement growth at six months of age.