Estimation of Genetic Parameters for Linear Classification Traits in Hanwoo cows Using Multiple Trait Animal Model
Authors: Lee Min-Ki , Kim Sungjin , Son Ji-Hyun , Lee Jung-Jae , Kim Kwan-Suk , Koo Yang-Mo 
Published: January 2024

This study was conducted to analyzed the statistical model of Hanwoo(Korean native cattle) cows linear classification trait, analyze the structure and environmental effects of linear classification data, and estimate genetic parameters for linear classification data by applying the analyzed environmental effects to use them as basic data for improving the body measurement and appearance of Hanwoo cows animals at the farm level. The data used in this study collected cows linear classification data that participated in the Hanwoo cows linear classification project promoted by the Korea Animal Improvement Association(KAIA) from 2014 to 2019 to quantify the body measurement of cows and use them for livestock improvement, selection, and culling. Among them, the most recent linear classification data was selected as analysis data, the previous data was deleted, outliers in the data were removed, and 369,723 Hanwoo cows suitable for Estimated Breeding Value(EBV) analysis were used. In addition, outliers were removed from the Hanwoo cows linear classification data, and the final score calculated by applying level and grade trait data and four data such as body height, body width, rump length, and pinbone width, which were found to have a high genetic correlation among 19 traits, was used. After removing outliers from the data, the most recent data was selected and used for analysis based on the linear classification month age when the linear classification data was repeatedly recorded for each parity. The least square mean analysis by linear classification trait showed that body height, which is most involved in body measurement and growth, steadily increased up to about 50 months, but there was no change thereafter. It was analyzed that the growth of Hanwoo cows ends on average when they are 50 months old, and the increase in body height slowed after the calf was produced. In the basic statistical analysis of linear classification traits, the average and standard deviation of body height, body width, rump length, pinbone width, and final score were analyzed as 6.22±1.33, 5.83±1.22, 5.88±1.20, 5.63±1.32 and 80.0±1.83. To analyzed the factors of environmental effects, the farm-birth year-birth season was set as one effect HYS(Herd-Year-Season) to establish the BCS(Body Condition Score), the classifier, the linear classification month, and the contemporary group, and a variance analysis was conducted to confirm that there was a high significant difference(p<0.001) with traits in BCS, classifier, linear classification month, and HYS. In the estimation of the genetic parameters of linear classification traits for Hanwoo cows, the heritability of body height, body width, rump length, pinbone width, and final score were estimated to be 0.42, 0.18, 0.34, 0.25 and 0.37, respectively. In the analysis of the genetic correlation coefficient between linear classification traits, body height, body width, rump length, pinbone width, and final score were analyzed as 0.80, 0.96, 0.95 and 0.94, respectively, pinbone width and final score were analyzed as 0.84, 0.84, and 0.89, rump length and pinbone width and final score were 0.94 and 0.92, and pinbone width and final score were analyzed as having a high genetic correlation of 0.97. In the phenotypic correlation coefficient analysis, body height, rump length, pinbone width, and final score were analyzed as 0.39, 0.63, 0.54, and 0.70, respectively, while body width, rump length, pinbone width, and final score were 0.40, 0.48, and 0.65, and rump length, pinbone width, and final score were analyzed as 0.61 and 0.70, and pinbone width and final score were 0.73, showing a high correlation between the traits. In the future, continuous research on linear classification traits should be conducted to find out the ideal body type ability of Hanwoo cows for growth ability and fertility trait, and it is believed that the productivity of Hanwoo should be improved through this.