Estimation of Breed and Environmental Effects on Economic Traits of Performance-Tested Pigs

This study was carried out to estimate the effects of breed and environment such as sex, test station, test year, test season, parity, initial and final weight on average daily gain, age at 90kg, backfat thickness, feed efficiency, lean percent and selection index on the basis of the performance data collected from 25,790 pigs of Duroc, Yorkshire and Landrace breeds which were performance-tested at the Korea Swine Testing Station from 1991 to 2002. The results obtained in the study are summarized as follows; 1. The means of the major economic traits were estimated as 959.95${\pm}$0.699g for average daily gain, 138.36${\pm}$0.072days for age at 90kg, 1.41${\pm}$0.001cm for backfat thickness, 2.33${\pm}$0.001 for feed efficiency, 56.71${\pm}$0.018% for lean percent and 221.65${\pm}$0.113 for selection index. 2. The effect of breed was statistically significant for all studied traits. Briefly, Duroc showed the best performance for the average daily gain and age at 90kg. Landrace had the best performances for the backfat thickness and lean meat percent. In feed efficiency and selection index, Yorkshire had a better score than other breeds. 3. The least-squares means of female and male for the traits studied were 923.05${\pm}$1.289g and 974.53${\pm}$0.856g for average daily gain, 139.74${\pm}$0.145days and 137.21${\pm}$0.097days for age at 90kg, 1.49${\pm}$0.002cm and 1.39${\pm}$0.002cm for backfat thickness, 2.43${\pm}$0.002 and 2.28${\pm}$0.002 for feed efficiency, 56.43${\pm}$0.034% and 56.81${\pm}$0.023% for lean percent and 211.37${\pm}$0.194 and 224.61${\pm}$0.129 for selection index. Therefore, males were superior to females for all traits examined. 4. The effect of test station was statistically significant for all traits except for selection index. Performances for age at 90kg, backfat thickness, feed efficiency and lean meat percent collected from Test station 2 were higher than those from Test station 1. However, Test station 1 showed better average daily gain. 5. The initial weight and final weight included as a covariate in this study had a significant influence on average daily gain, age at 90kg, backfat thickness, feed efficiency and selection index. From the absolute values of the estimated regression coefficients, it was inferred that the final weight had greater effect for the investigated traits than the initial weight.

검정소 검정돈의 품종 및 환경요인의 효과 추정

본 연구는 1991년부터 2002년 2월까지 대한양돈협회 공인 제1, 제2 종돈 능력검정소에서 검정이 완료된 Duroc종, Landrace종, Yorkshire종의 3개 품종 25,790두를 대상으로 돼지의 주요 경제 형질인 일당증체량, 등지방두께, 90kg 도달일령, 사료요구율, 정육율 및 선발지수에 영향을 미치는 품종, 성 및 환경요인의 효과를 추정하였다. 본 연구에서 얻어진 결과를 요약하면 다음과 같다. 1) 각 형질의 최소자승 평균은 일당증체량 959.95${\pm}$0.699g, 90kg 도달일령 138.36${\pm}$0.072일, 등지방 두께 1.41${\pm}$0.001cm, 사료요구율 2.33${\pm}$0.001, 정육율 56.71${\pm}$0.018% 및 선발지수 221.65${\pm}$0.113이었다. 2) 모든 형질에서 품종간에 유의한 차이를 보였으며, 일당증체량과 90kg 도달일령은 Duroc종(966.44${\pm}$1.361g, 137.10${\pm}$0.153일)이 가장 우수하고 Yorkshire종(938.79${\pm}$1.026g, 139.96${\pm}$0.116일)이 가장 불량하였다. 등지방 두께는 Landrace종(1.35${\pm}$0.002cm)이 가장 우수하고, Duroc종(1.60${\pm}$0.002cm)이 가장 불량하였다. 사료요구율은 Yorkshire종(2.34${\pm}$0.002)이 가장 우수하고 Landrace종(2.38${\pm}$0.003)이 가장 불량하였다. 정육율은 Landrace종(57.48${\pm}$0.037%)이 가장 우수하고 Duroc종(55.07${\pm}$0.035%)이 가장 불량하였다. 선발지수는 Yorkshire종(219.78${\pm}$0.154)이 가장 우수하고 Duroc종(214.97${\pm}$0.205)이 가장 불량하였다. 3) 각 형질에 대한 성별 최소자승 평균은 암퇘지와 수퇘지에서 각각 일당 증체량이 923.05${\pm}$1.289g, 974.53${\pm}$0.856g, 90kg 도달일령이 139.74${\pm}$0.145일, 137.21${\pm}$0.097일, 등지방 두께가 1.49${\pm}$0.002cm, 1.39${\pm}$0.002cm, 사료요구율이 2.43${\pm}$0.002, 2.28${\pm}$0.002, 정육율은 56.43${\pm}$0.034%, 56.81${\pm}$0.023% 및 선발지수가 211.37${\pm}$0.194, 224.61${\pm}$0.129로 조사된 모든 형질에 있어서 수퇘지가 암퇘지보다 우수하였다. 4) 검정소의 효과는 선발지수를 제외한 조사된 모든 형질에서 유의한 차이를 보였으며, 1검정소와 2검정소의 최소자승 평균은 각각 90kg 도달일령이 138.64${\pm}$0.117일, 138.32${\pm}$0.126일, 등지방 두께가 1.45${\pm}$0.002cm, 1.43${\pm}$0.002cm, 사료요구율이 2.37${\pm}$0.002, 2.34${\pm}$0.002, 정육율이 56.34${\pm}$0.027%, 56.90${\pm}$0.029%로 2검정소가 우수하였고, 일당증체량은 957.48${\pm}$1.039g, 940.09${\pm}$1.120g으로 1검정소가 우수하였다. 5) 본 연구에서 공분산 성분으로 포함된 검정개시체중과 검정종료체중은 일당증체량, 90kg 도달일령, 등지방 두께, 사료요구율 및 선발지수에 유의적으로 영향하였다. 추정된 회귀계수는 검정개시체중에 있어서 각각 1.7944${\pm}$0.21961, -0.3169${\pm}$0.02476, -0.0009${\pm}$0.00039, 0.0007${\pm}$0.00042 및 0.1950${\pm}$0.03304, 검정종료체중에 있어서는 각각 7.9414${\pm}$0.25182, -0.7222${\pm}$0.02839, -0.0038${\pm}$0.00045, -0.0008${\pm}$0.00048 및 1.0279${\pm}$0.03790으로 절대값을 비교하여 볼 때, 검정개시체중보다는 검정종료체중이 조사된 형질에 더욱 크게 영향하였다.