Conformation traits of Brown, Simmental and Holstein breed calves were studied to estimate the genetic and environmental parameters using data from two classification systems. Calves were classified in the period 2000 – 2010 between the age of one to 51 days. Beside the chest girth as a measurement in cm five traits were scored. At the beginning, the traits such as muscularity, form, body depth, body length and width were scored on the scale from 1 to 3 or 1 to 9 while in the year 2008 the system of classification changed to scores from 1 to 5 for all traits. Due to high variability of the data their thorough cleaning and homogenisation was required. Uni- and bivariate analyses using animal model methodology were performed. The effects of technician by year of classification, classification age class, birth season in months by years were treated as fixed and the herd by year of classification and additive genetic effect as random. Heritability estimates for data from the new classification system are rather higher (0.05-0.29) than those from the old system. Genetic correlations between estimates of two classification systems are very high, i. e. in a range from 0.74 to 0.97, which indicates a strong genetic relationship between the old and the new system of classification. The only exceptions were form and body depth in Simmental breed. In the chest girth the estimates of heritability from 0.16 to 0.27 were obtained.

cattle; conformation traits in calves; genetic parameters; classification systems

Published by University of Zagreb, Faculty of Agriculture, Zagreb, CROATIA
Sponsored by Ministry Science and Education of the Republic of Croatia