Estimation of growth curve in Hanwoo steers using progeny test records

Abstract

A total of 6,973 steer growth records of Hanwoo breeding bull’s progeny test data collected from 1989 to 2015 were analyzed to identify the most appropriate growth curve among three growth curve models (Gompertz, Logistic and von Bertalanffy). The Gompertz growth curve model equation was W t = 990.5e -2.7479e -0.00241t , the Logistic growth curve model equation was W t =772(1+8.3314e -0.00475t ) -1 , and the von Bertalanffy growth curve model equation wasW t = 1,196.4(1-0.642e -0.00162t ) 3 . The Gompertz model parameters A, b, and k were estimated to be 990.5 ± 10.27, 2.7479 ± 0.0068, and 0.00241 ± 0.000028, respectively. The inflection point age was estimated to be 421 days and the weight of inflection point was 365.3 kg. The Logistic model parameters A, b, and k were estimated to be 772.0 ± 4.12, 8.3314 ± 0.0453, and 0.00475 ± 0.000033, respectively. The inflection point age was estimated to be 445 days and the weight of inflection point was 385.0 kg. The von Bertalanffy model parameters A, b, and k were estimated to be 1196.4 ± 18.39, 0.646 ± 0.0010, and 0.00162 ± 0.000027, respectively. The inflection point age was estimated to be 405 days and the weight of inflection point was 352.0 kg. Mature body weight of the von Bertalanffy model was 1196.4 kg, the Gompertz model was 990.5 kg, and the Logistic model was 772.0 kg. The difference between actual and estimated weights was similar in the Logistic model and the von Bertalanffy model. The difference between market weight and estimated market weight was the lowest in the Gompertz model. The growth curve using the von Bertalanffy model showed the lowest mean square error.