Korea Animal Improvement Association Research Articles

Estimation of Genetic Parameters for Linear Classification Traits in Hanwoo cows Using Multiple Trait Animal Model

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.

Estimation the genetic parameters and evaluating the correlation between the maternal linear type traits and the birth weight of the progeny in Hanwoo cows

This study aimed to investigate the correlation between the linear type traits of mother cows (dams) and the birth weight(BW) of the progeny. The study used data collected between 2002 and 2018 by the Korea Animal Improvement Association (KAIA). This study evaluated the data specifically with respect to 19 traits. A statistical model was established to estimate the correlation between the maternal linear classification traits and the progeny BW. The significance of each statistical variable was analyzed using the generalized linear model (GLM) method in the SAS package 9.1.3 software, while the genetic parameters were estimated using the BLUPF90 Family program. The BW of Hanwoo cows increased by approximately 0.4 kg each year; however, the BW heritability was moderate (0.23). The linear classification traits showed values of 0.34, 0.37, 0.11, 0.45, 0.31, and 0.40, for ST (Vertical distance from the apex of the rump to the ground), BL (Horizontal distance between anterior shoulder point to the posterior extremity of the pin bone), RA (The slope from the rump to the pin bone), RL (Horizontal distance from the anterior rump to the tip of the pin bone), PBW (Lateral width of pin bone), and FS (Final score), respectively, with moderate heritability for all traits, except RA. The BW of the progeny showed phenotypic correlations of 0.06, -0.01, 0.03, and 0.04, and genetic correlations of 0.09, 0.03, 0.02, and -0.04 with ST, BL, RL, and PBW, respectively. The average parity in Hanwoo cows increased from 2.5 in 2016 to 2.8 in June 2020. There is a low genetic correlation between the maternal linear classification traits and the BW of the progeny. An increase in the parity of dams and a greater accumulation of progeny BW data and test records could lead to the accurate evaluation of the BW as a breeding objective trait.

Contribution analysis of carcass traits on auction price for Hanwoo steers in the Yeongnam region of Korea

In this study, Data were the carcass grade on each 53,829 head of hanwoo steers slaughtered 3 years before (2017, 2018, 2019), 32,910 head of hanwoo steers slaughtered after (2020, 2021, 2022) COVID-19 at Yeongnam region and 54,369 head of hanwoo steers slaughtered same period at except for Yeongnam region. To find out the contribution of carcass traits to auction price and total price were analyzed through regression coefficients by using multiple regression analysis. As environmental factors affecting these carcass traits, slaughter year and slaughter season were set and analyzed through the least square method. The results of slaughter year showed that the grade of carcass traits in Yeongnam region increased over the years. In addition, in the slaughter season, the grade of carcass traits in the fall was found to be excellent. According to the contribution analysis, the results of the contribution ratio to auction price of before and after COVID-19 in Yeongnam region and after COVID-19 in all regions except Yeongnam were the same in order of marbling score, backfat thickness, eye muscle area, carcass weight. Also, the contribution ratio to total price were the same in order of carcass weight, marbling score, backfat thickness, eye muscle area. The general carcass grade is intended to use and analyze data from Yeongnam region, which has excellent backfat thickness and carcass weight, also has the largest number of elite cows selected through the verification work of elite cow by Korea Animal Improvement Association, and use it as a means for strategies to increase farm’s income and advance to high quality about Korean beef.

The Estimation of Genetic Parameters for Longevity According to Lactation Period Using a Multiple Trait Animal Model in Korean Holstein Cows.

Simple SummarySouth Korea dairy farmers are less interested in improving milk production-related traits for various reasons, including the milk production quota system. Consequently, they have become more interested in improving traits associated with longevity. Therefore, the purpose of this study was to analyze the culling patterns and survival rates of Korean Holstein cows and evaluate genetic characteristics related to parity and longevity of each lactation by using test data collected in South Korea. This study presents evidence that individuals’ genetic backgrounds differ with respect to differences in the individuals’ survival periods. Three lactation periods in each parity were split according to lactation days: 0–90 days (1), 91–299 days (2), and 300 days to the next calving (3). The heritability of the first, second, and third parities were 0.020, 0.028, and 0.039, respectively. In all parities, the heritability in late-lactation was higher than that in early- and mid-lactations. Most genetic correlations for survival in the first parity were higher than those in the second and third parities. The genetic correlation in the same lactation in the first and second parities were lower than those in the intervals in the second and third parities. The results of this study may serve as a basis for developing a more accurate model for evaluating longevity traits in South Korea.Longevity is closely related to the survival rate of dairy cattle and refers to the period during which the cow has economic value, from first calving to culling. The purpose of this study was to analyze the culling patterns and survival rates of Korean Holstein cows and evaluate genetic characteristics related to parity and longevity of each lactation by using the test day milk yield collected in South Korea. The performance data of the dairy cattle were collected from 2004 to 2019 by the Nonghyup Dairy Cattle Improvement Center. The collected 1,702,304 records were used as pedigree data through the Korea Animal Improvement Association. The lactation period was divided into early-lactation (0–90 days: L1.1, L2.1, and L3.1), mid-lactation (91–299 days: L1.2, L2.2, and L3.2), and late-lactation (300 days-next parity: L1.3, L2.3, and L3.3). The heritability of longevity for the first, second, and third parity was 0.020, 0.028, and 0.039, respectively. In all parities, the heritability in late-lactation was higher than that in early- and mid-lactation. Most genetic correlations for survival in the first parity were higher than those in the second and third parities. The results of this study may serve as a basis for developing a more accurate model for evaluating longevity traits in South Korea.

Estimation of the genetic milk yield parameters of Holstein cattle under heat stress in South Korea.

ObjectiveThe objective of this study was to investigate the genetic components of daily milk yield and to re-rank bulls in South Korea by estimated breeding value (EBV) under heat stress using the temperature-humidity index (THI).MethodsThis study was conducted using 125,312 monthly test-day records, collected from January 2000 to February 2017 for 19,889 Holstein cows from 647 farms in South Korea. Milk production data were collected from two agencies, the Dairy Cattle Genetic Improvement Center and the Korea Animal Improvement Association, and meteorological data were obtained from 41 regional weather stations using the Automated Surface Observing System (ASOS) installed throughout South Korea. A random regression model using the THI was applied to estimate genetic parameters of heat tolerance based on the test-day records. The model included herd-year-season, calving age, and days-in-milk as fixed effects, as well as heat tolerance as an additive genetic effect, permanent environmental effect, and direct additive and permanent environmental effect.ResultsBelow the THI threshold (≤72; no heat stress), the variance in heat tolerance was zero. However, the heat tolerance variance began to increase as THI exceeded the threshold. The covariance between the genetic additive effect and the heat tolerance effect was −0.33. Heritability estimates of milk yield ranged from 0.111 to 0.176 (average: 0.128). Heritability decreased slightly as THI increased, and began to increase at a THI of 79. The predicted bull EBV ranking varied with THI.ConclusionWe conclude that genetic evaluation using the THI function could be useful for selecting bulls for heat tolerance in South Korea.

Genetic parameter estimation for milk β-hydroxybutyrate and acetone in early lactation and its association with fat to protein ratio and energy balance in Korean Holstein cattle.

ObjectiveThe objective of this study was to estimate the genetic parameters for milk β-hydroxybutyrate (BHBA), acetone (Ac), fat protein ratio (FPR), and energy balance (EB) using milk test day records and investigate the effect of early lactation FPR and EB on milk ketone body concentrations.MethodsTotal 262,940 test-day records collected from Korea Animal Improvement Association during the period of 2012 to 2016 were used in this study. BHBA and Ac concentrations in milk were measured by Fourier transform infrared spectroscopy (FTIR). FPR values were obtained using test day records of fat and protein percentage. EB was calculated using previously developed equation based on parity, lactation week, and milk composition data. Genetic parameters were estimated by restricted maximum likelihood procedure based on repeatability model using Wombat program.ResultsElevated milk BHBA and Ac concentrations were observed during the early lactation under the negative energy balance. Milk FPR tends to decrease with the decreasing ketone body concentrations. Heritability estimates for milk BHBA, Ac, EB, and FPR ranged from 0.09 to 0.14, 0.23 to 0.31, 0.19 to 0.52, and 0.16 to 0.42 respectively at parity 1, 2, 3, and 4. The overall heritability for BHBA, Ac, EB and FPR were 0.29, 0.32, 0.58, and 0.38 respectively. A common pattern was observed in heritability of EB and FPR along with parities.ConclusionFPR and EB can be suggested as potential predictors for risk of hyperketonemia. The heritability estimates of milk BHBA, Ac, EB, and FPR indicate that the selective breeding may contribute to maintaining the milk ketone bodies at optimum level during early lactation.

Impact of environmental factors on milk β-hydroxybutyric acid and acetone levels in Holstein cattle associated with production traits

The objective of this study was to estimate the environmental factors affecting milk β-hydroxybutyric acid (BHBA) and acetone (Ac) concentrations in Holstein cattle. A total of 264,221 test-day records collected from the Korea Animal Improvement Association (KAIA) during the period of 2012 to 2014 were used in this study. Analysis of variance (ANOVA) was performed to determine the factors significantly affecting ketone body concentrations. Parameters considered in the model were season of test, season of calving, parity, lactation stage, and milk collecting time (AM and PM). According to the ANOVA, the R² for milk BHBA and Ac were 0.5226 and 0.4961, respectively. ‘Season of test’ showed a considerable influence on ketone body concentration. Least square (LS) means for milk BHBA concentrations was the lowest (39.04 μM) in winter while it increased up to 62.91 μM in summer. But Ac concentration did not significantly change along with ‘season of test’. The means of milk BHBA and Ac concentrations were high at first lactation stage, low around second lactation stage, and then gradually increased. Cows milked in the morning had lower mean BHBA and Ac concentrations (48.49 μM and 121.69 μM, respectively) in comparison to those milked in the evening (53.46 μM and 130.42 μM, respectively). The LS means of BHBA and Ac slightly increased over parities. These results suggest that proper maintenance of milk collection, herd management programs, and evaluation of ketone body levels in milk should be considered for the efficient management of resistance to ketosis.

Genetic Parameters of Milk β-Hydroxybutyric Acid and Acetone and Their Genetic Association with Milk Production Traits of Holstein Cattle.

This study was conducted to estimate the genetic parameters of β-hydroxybutyrate (BHBA) and acetone concentration in milk by Fourier transform infrared spectroscopy along with test-day milk production traits including fat %, protein % and milk yield based on monthly samples of milk obtained as part of a routine milk recording program in Korea. Additionally, the feasibility of using such data in the official dairy cattle breeding system for selection of cows with low susceptibility of ketosis was evaluated. A total of 57,190 monthly test-day records for parities 1, 2, and 3 of 7,895 cows with pedigree information were collected from April 2012 to August 2014 from herds enrolled in the Korea Animal Improvement Association. Multi-trait random regression models were separately applied to estimate genetic parameters of test-day records for each parity. The model included fixed herd test-day effects, calving age and season effects, and random regressions for additive genetic and permanent environmental effects. Abundance of variation of acetone may provide a more sensitive indication of ketosis than many zero observations in concentration of milk BHBA. Heritabilities of milk BHBA levels ranged from 0.04 to 0.17 with a mean of 0.09 for the interval between 4 and 305 days in milk during three lactations. The average heritabilities for milk acetone concentration were 0.29, 0.29, and 0.22 for parities 1, 2, and 3, respectively. There was no clear genetic association of the concentration of two ketone bodies with three test-day milk production traits, even if some correlations among breeding values of the test-day records in this study were observed. These results suggest that genetic selection for low susceptibility of ketosis in early lactation is possible. Further, it is desirable for the breeding scheme of dairy cattle to include the records of milk acetone rather than the records of milk BHBA.

젖소의 장수성과 수익성 관계 연구

Records of 490,767 cows collected from 1990 to 2012 by dairy herd milk test of National Agriculture Cooperative Federation The pedigree of dairy cattle were provided by Korea Animal Improvement Association. The data were used to analyze the longevity of dairy cows with the life traits such as days in milk, number of lactation, productive life, and life span. The data were also used to investigate genetic relationship of these longevity traits with profitability of dairy cows, including heritability and genetic correlation. The profitability was calculated with simulation of milk income and production costs for individual cows. Days in milk among the traits had -0.287, -0.572 and -0.536 of genetic correlation with number of lactations, productive life and lifespan, respectively. The heritabilities of life span, number of lactations, productive life, and days in milk were found to be 0.045, 0.047, 0.059 and 0.081, respectively. Genetic correlations of profit with productive life, number of lactations, and days in milk were identified as 0.072, 0.080, 0.098 and 0.101. These results suggested that days in milk was most desirable traits to represent longevity of Holstein dairy cattle. In general, since longevity and profitability were close genetic relationship each other, genetic improvement of longevity is necessary for better profitable cows.

Genetic parameter estimation in seedstock Swine population for growth performances.

The objective of this study was to estimate genetic parameters that are to be used for across-herd genetic evaluations of seed stock pigs at GGP level. Performance data with pedigree information collected from swine breeder farms in Korea were provided by Korea Animal Improvement Association (AIAK). Performance data were composed of final body weights at test days and ultrasound measures of back fat thickness (BF), rib eye area (EMA) and retail cut percentage (RCP). Breeds of swine tested were Landrace, Yorkshire and Duroc. Days to 90 kg body weight (DAYS90) were estimated with linear function of age and ADG calculated from body weights at test days. Ultrasound measures were taken with A-mode ultrasound scanners by trained technicians. Number of performance records after censoring outliers and keeping records pigs only born from year 2000 were of 78,068 Duroc pigs, 101,821 Landrace pigs and 281,421 Yorkshire pigs. Models included contemporary groups defined by the same herd and the same seasons of births of the same year, which was regarded as fixed along with the effect of sex for all traits and body weight at test day as a linear covariate for ultrasound measures. REML estimation was processed with REMLF90 program. Heritability estimates were 0.40, 0.32, 0.21 0.39 for DAYS90, ADG, BF, EMA, RCP, respectively for Duroc population. Respective heritability estimates for Landrace population were 0.43, 0.41, 0.22, and 0.43 and for Yorkshire population were 0.36, 0.38, 0.22, and 0.42. Genetic correlation coefficients of DAYS90 with BF, EMA, or RCP were estimated to be 0.00 to 0.09, −0.15 to −0.25, 0.22 to 0.28, respectively for three breeds populations. Genetic correlation coefficients estimated between BF and EMA was −0.33 to −0.39. Genetic correlation coefficient estimated between BF and RCP was high and negative (−0.78 to −0.85) but the environmental correlation coefficients between these two traits was medium and negative (near −0.35), which describes a highly correlated genetic response to selection on one or the other of these traits. Genetic Trends of all three breeds tend to be towards bigger EMA or greater RCP and shorter DAYS90 especially from generations born after year 2000.

국내 Holstein종 젖소의 경제형질과 착유량에 따른 소득의 유전모수 추정

Korean Animal Improvement AssociationABSTRACTThe data including milk yields, fat and protein percent for 628,395 heads collected by National Agricultural Cooperative Federation, 15 type traits and final score for 62,262 heads collected by Korea Animal Improvement Association, which were born in 1998 to 2004, and net profits calculated from milk price and raising expenses of individuals were used to estimate genetic parameters. The highest positive genetic correlation, 0.81, was shown between body depth(BD) and loin strength(SR). Genetic correlations between body depth(BD) and udder depth(UD), front teat placement(TP) and front teat length(TL) were '0.23, which were lowest among the linear type traits. Furthermore, medium level of negative genetic correlations were shown the milk yield with milk contents rate traits. Mostly low level of positive genetic correlations were shown between the milk traits and linear score traits except milk yield and stature. Most of the genetic correlations of between the linear score traits and net profit were low level of positive or negative genetic correlations. Among the genetic correlations, body depth(BD), angularity(DF) and rear attachment width(UW), and final score(FS) with net profit were high as 0.17, 0.17, 0.18 and 0.18, respectively. Finally all of the genetic correlations between net profit and milk traits were positive and higher than the linear traits with positive genetic correlations. The results of this study suggest that net profit has been related with the linear traits, such as body depth(BD), angularity(DF) and rear attachment width(UW) traits, and furthermore, milk traits including yield and contents rates influence positively and greatly on net profit. (Key words :Milk yield traits, Linear type traits, Net profit, Genetic parameter, Genetic parameter)

반복모형을 이용한 한우 초음파 측정형질의 유전모수추정

본 연구는 한우 암소 초음파 측정자료 특징을 알아보고, 측정형질에 대한 유전모수를 추정하여 육질 또는 육량 개량을 위한 기초자료를 제공하기 위해 수행되었으며, 2001년부터 2009년까지 한국종축개량협회에 의해 측정된 한우 암소 36,893두를 이용하였고, 그 중 반복기록이 있는 개체는 7,913두였다. 유전모수 추정을 위하여 반복개체모형을 이용하였으며, 유전모수 추정에는 REMLF90 (Miztal, 2001)을 이용하였다. 유전모수 추정모형의 설정을 위하여 흉위, 영양도 및 초음파 측정치에 대한 출생년도, 출생계절, 측정년도, 측정계절, 측정지역, 측정연령 등의 환경효과를 추정하였다. 반복개체모형으로 추정된 배최장근단면적, 등지방두께 및 근내지방도에 대한 유전력이 각각 0.31, 0.38, 0.27로 나타났고, 다형질개체모형으로 추정한 유전력은 각각 0.02, 0.09, 0.07로 낮게 추정되었다. 반복개체모형을 이용한 반복력은 배최장근단면적, 등지방두께, 근내지방도가 각각 0.46, 0.57, 0.39로 나타났다. 분석모형 간의 추정치의 차이를 비교 할 때 반복모형에서의 유전력과 반복력이 높게 추정되었다. 따라서 반복형질 값을 가진 형질들의 측정치를 표준화하여 한우암소개량을 위한 기초자료로 활용된다면 유전능력평가와 개량사업 비용절감에 도움이 될 것으로 기대된다. The present study data were obtained from 36,894 cows in Korea Animal Improvement Association from 2001 to 2009 which was subjected for ultrasound measurements (eye muscle area, back-fat thickness, marbling score) and descent. Repeated record models were carried out using 7,913 of 36,894 of total animal traits. The ultrasound measured traits and performance test data were used to study the chest girth, body condition score, eye muscle area, back-fat thickness and marbling score with genetic correlation and parameters for the ultrasound measured traits using REMLF90 program. Genetic correlation of eye muscle area with back-fat thickness, marbling score and back-fat thickness with marbling score were noticed in repeated records animal model as 0.69, 0.54, and 0.59, whereas in multiple trait animal model method were 0.07, 0.66, and 0.39, respectively. Repeated records of animal models were used as positive correlation of traits. Multiple trait animal models were used as negative correlation of eye muscle area with marbling score. The analysis on repeat records of animal models using ultrasound measurements about Korean cattle showed positive effects for each traits. In comparison differences between the repeat records of animal models and multiple trait animal models was found with higher traits of her, the heritability and repeatability was found higher in repeat records animal models. In light of these assessments, carcass traits by ultrasound measurements are expected to help and improve an accurate analysis of each trait and if the research analysis using repeat records of animal models continue when we estimate genetic ability of these traits.

국내 듀록의 종돈장간의 교류현황과 유전능력평가에 미치는 효과

국내 듀록 품종 종돈의 교류현황과 또한 유전자원 교류가 국가단위의 유전능력평가에 미치는 영향을 평가하고, 돼지개량네트워크 사업을 통한 돼지개량 전략 마련을 위한 기초자료를 수집하기 위하여 한국종축개량협회의 등록 및 검정 자료를 분석하였다. 자료는 세 곳의 등지방 두께(어깨, 등, 허리)와 등심단면적, 90 kg 도달일령 그리고 일당증체량 형질을 포함하고 있으며, 1987년부터 2010년까지 총 235,511건의 등록 자료와 70,747건의 검정자료를 이용하였다. 수집된 듀록 자료를 분석한 결과, 종돈장간의 유전자원의 교류는 극히 미미한 수준으로 나타났다. 등록 후에 검정까지 수행 되어진 자료의 수는 더욱 적은 것으로 나타났고, 유전능력평가를 위해 필요한 일정규모의 두 수를 가진 종돈장의 수는 더욱 적었다. 혈연관계의 이용정도에 따라 세 가지 분류의 자료(개별 종돈장, 두개의 종돈장 그룹, 전체 종돈장)를 이용한 유전능력 평가 및 유전 모수의 추정에 있어서, 개별 종돈장 분석에서 종돈장간에 유전모수추정에 있어 거점 종돈장에 비하여 종속 종돈장의 유전력이 높은 경향을 보여 주었다. 유전력 추정 오차는 개별 종돈장, 두 그룹, 전체 집단 순으로 작게 나타났다. 유전분산이 종속 종돈장들에서 크게 나타남으로써 종속 종돈장들의 유전적 균일성이 거점 종돈장들에 비해 낮은 것으로 나타났다. 근친계수의 추정에서 차이를 보였으며, 개별 종돈장, 거점 종돈장과 종속 종돈장, 그리고 전체 집단을 평가하였을 때 각각 평균 근친이 1.12, 0.95 그리고 1.53으로 나타나 종돈장 간의 혈연관계를 고려한 전체 집단 평가에서 근친이 높았다. 추정된 육종가에 의한 상관계수에서 개별농가의 평가와 전체평가간의 상관이 가장 낮았다. 반면에 sub-population 평가와 개별농가 평가, 그리고 전체 평가는 이보다 상관이 높게 나타났다. 그러나 농장별 평가와 전체평가간의 상관계수가 이동된 종돈에서 형질별로 0.22에서 0.45, 그리고 전체 종돈에서 0.24에서 0.72의 범위로 비교적 낮게 나타났다. 연구된 결과들은 개별 종돈장 평가 보다는 국가단위의 유전능력평가가 혈연관계를 더 많이 이용하고, 돼지개량네트워크 사업이 종돈장간의 연결성을 증대시켜 국가단위 유전능력평가의 정확도에 기여한다고 사료된다. The study was carried to identify the impact on nation-wide genetic evaluation and to obtain basic materials for the development of strategies in Swine Improvement Network Project (SINP). Data consisted of pedigree records of 235,511 and performance records of 70,747 for Duroc from 1987 to 2010 were collected by Korea Animal Improvement Association. Performance traits included three point back fat thickness (Shoulder, Belly, Waist), loin area, days to 90 kg and average daily gain. Exchange of genetic resources cross the breeding farms was not high, and furthermore the sizable farms which can accommodate genetic evaluation within the farm were scarce. Three data sets (individual farm evaluation: I, two sub-group evaluation: S, and whole eight farm evaluation: P) were used for genetic analysis. Genetic variances were larger in subordinate farms than in joiners farms for connectedness, and consequently the heritabilities were generally higher in subordinate farms than in joiner farms with I. The standard errors of heritability were small in the order of I, S and P. Estimated average inbreeding coefficients were 1.12%, 0.95% and 1.53% for joiner and subordinate group with S and population with P, respectively. The estimated correlations of breeding values with I and P were lowest. The correlations of breeding values with I and P for traits ranged 0.22 to 0.45 for moved parent animals and 0.24 to 0.72 for all animals. The results in the study suggest that nation-wide evaluation uses more pedigree information and improves accuracy. Furthermore SINP for connectedness could help to improve the accuracy of evaluation.

한우 씨수소의 근교계수와 유효집단크기의 추정

본 연구는 지금까지 보증 및 후보씨수소로 선발된 씨수소에 대하여 연도별 평균 근교 및 혈연계수를 추정하고 씨수소의 유효집단크기를 추정하여 현재 한우개량 체계의 문제를 도출하여 발전된 대안을 제시하고자 실시하였다. 분석에 이용된 자료는 한우개량사업소로부터 1983년부터 2008년까지 1,128두의 당 후대검정 씨수소자료와 한국종축개량협회로부터 3,760두에 대한 혈통자료를 받아 이용하였다. 보증 및 후보씨수소의 평균 근교계수는 0.04에서 0.97%의 분포로 추정되었으며, 평균 혈연계수는 0.10에서 6.82%의 분포로 추정되었다. 유효집단 크기는 1983년부터 2008년까지 26년간 평균 근교비율을 이용하였을 때 220두로 추정되었다. 근교수준은 최근 2년간 급격히 증가하였고, 평균 혈연계수 역시 점차 증가하는 추세이다. 유효집단크기도 최근 5년의 근교비율로 추정하였을 때 47두로 작게 추정되었다. 보증씨수소 선발시 후대검정우의 도체성적에 의한 유전능력평가 자료의 활용뿐만 아니라, 근교 및 혈연계수를 고려하고 한우의 유전적 다양성의 보존과 근교를 피하기 위하여 현행의 보증씨수소 두수를 증가시켜 유효집단크기를 높여야 될 필요성이 있다고 사료된다. This study was carried out to estimate average inbreeding coefficients, relatedness and effective population size of breeding bulls and to suggest optimal alternatives on problems of current Hanwoo improvement system. Data on proven and young bulls were obtained from 1,128 heads of Livestock Improvement Main Center from 1983 to 2008. Pedigree information on proven and young bulls was obtained from 3,760 heads of Korea Animal Improvement Association. Average inbreeding coefficients and average relatedness of proven and young bulls were estimated at the range of 0.04-0.07%, 0.10-6.82%, respectively. Effective population size was estimated for 220 heads from the average rate of inbreeding of last 26 years. Average inbreeding coefficient is rising rapidly for the last two years as well as average relatedness. Effective population size was estimated for 47 heads for the last five years. These results suggest that selection criteria of proven bulls should include not only genetic evaluation of carcass performance from progeny-test, but also inbreeding and relationship coefficients, in order to maintain genetic variability of Hanwoo. In addition, effective population size should be increased by increasing the number of proven bulls.

Study on Genetic Evaluation for Linear Type Traits in Holstein Cows

The objectives of this study were to i) investigate genetic performance for linear type traits of individual Holstein dairy cows, especially focusing on comparative traits, and to estimate genetic variances for these traits using actual data, and ii) compare genetic performance and improvement of progeny by birth country of the cows. Linear type traits defined with five comparative traits on this study were general stature composite (GSC), dairy capacity composite (DCC), body size composite (BSC), foot and leg composite (FLC), and udder composite (UDC). These traits were scored from 1 to 6 with 1 = poor, 2 = fair, 3 = good, 4 = good plus, 5 = very good and 6 = excellent. Final scores (FS) were also included in this study. Data used was collected from the years 2000 to 2004 by the Korea Animal Improvement Association (KAIA). Only data of more than five tested cows by herd appraisal date and by sires having more than ten daughters were included to increase the reliability of the data analyses. A total of 30,204 records of the selected traits, which was collected from 26,701 individuals having pedigree information were used. Herd appraisal date, year of age, lactation stage (grouped by month), and time lagged for milking (in hours) were assumed as fixed effects on the model. Animal additive genetic effects considering pedigree relationship and residual errors were assumed with random effects. Year of age at appraisal date was classified from one to nine years of age, assigning the value of nine years of age for animals that were greater than or equal to nine years of age. From our results, the estimate for heritability was 0.463, 0.346, 0.473, 0.290, and 0.430 on GSC, DCC, BSC, FLC and UDC, respectively. The estimate for FS heritability was 0.539. The greatest breeding values for GSC were estimated for Canada, with the breeding values for American lines increasing for 10 years starting in 1989 but tending to decrease after that until 2004. For DCC, the breeding values for American and Canadian lines showed similar patterns until 1999, after which the breeding values for the American lines declined sharply. For BSC, data from Korea, Canada and the USA followed similar trends overall except when the breeding values of the American lines decreased starting in 1999. Overall, the methods used to evaluate genetic performance in this study were acceptable and allowed for the discovery of differences by country of genetic origin, likely due in part to the American use of selection indexes based primarily on milk yield traits until methods for evaluating other traits began to emerge.

주성분 분석을 이용한 거세한우의 체형분류에 관한 연구

1997년부터 2001년까지 (사)한국종축개량협회의 전국한우능력평가대회에 출품된 642두의 거세한우의 도축 전까지 4회에 걸쳐 주요 10개 부위의 체형 측정치를 조사하여 주성분 분석을 이용하여 체형을 분류하였으며, 각 체형 측정치의 주성분 지수와 도체 형질과의 상관관계를 분석하였으며, 그 결과를 요약하면 다음과 같다. 1. 1차, 2차, 3차 및 4차 체형 측정치의 principal component(이하 P.C) 1의 분산은 각각 7.610, 8.297, 7.269 및 5.739로서 전체분산 중 76.0%, 83.0%, 72.7% 및 57.4%를 나타낼 수 있었고, P.C 1, P.C 2, P.C 3의 합은 전체분산 중 각각 86.69%, 90.49%, 84.62% 및 77.26%를 나타났다. 2. 각 차수별 체형 측정치의 P.C 1의 모든 계수가 양(+)이어서 일반적으로 좋은 체구의 크기를 나타내었으며, 체구의 크기에 가장 크게 영향을 미치는 형질은 흉심(0.328<TEX>${\sim}$</TEX>0.339)과 요각폭(0.325<TEX>${\sim}$</TEX>0.341)이였다. 또한 P.C 2, P.C 3 및 P.C 4는 각 차수별로 다양하게 나타났다. 3. 1차, 2차, 3차 및 4차 체형 측정치의 주성분 지수들과 도체형질간의 상관계수 추정에서 대부분의 분산을 차지하는 P.C 1은 도체중(0.539<TEX>${\sim}$</TEX>0.755), 일당증체량(0.256<TEX>${\sim}$</TEX>0.564), 등지방두께(0.227<TEX>${\sim}$</TEX>0.280) 및 배최장근단면적(0.187 <TEX>${\sim}$</TEX>0.344)간에 정(+)의 상관을 보였으며, 육량지수(－0.246<TEX>${\sim}$</TEX>－0.110)와는 부(－)의 상관을 보였고, 근내지방도(0.066<TEX>${\sim}$</TEX>0.099)와는 대부분 유의적인 상관을 보이지 않거나 낮은 상관을 보였고, P.C 2, P.C 3 및 P.C 4는 주성분 지수들의 값에 따라 도체형질과 다양한 상관관계를 보였다. 단일 체형형질과 도체형질간의 상관 그리고 P.C 1의 주성분 지수와 도체 형질과의 상관간에는 큰 차이가 없었다. Data were consisted of the ten body measurements (withers height, rump height, body length, chest depth, chest width, rump width, rump length, thurls width, hipbone width and chest girth) of 642 steers (Korean cattle), which was entered in the National Beef Quality Contest hosted by the Korea Animal Improvement Association from 1997 to 2001. A principal components analysis was used to classify the body types of the steers, and estimate the correlations between carcass traits and principal components for the body measurements of the first, second, third and fourth period, respectively. The first principal component of body measurements at the first, second, third and fourth period accounted for 76.0%, 83.0%, 72.7% and 57.4% of the total variance, respectively. The sum of first, second and third principal component at each period accounted for 86.69%, 90.49%, 84.62% and 77.26% of the total variance, respectively. At each period, all the first principal component of the body measurements were positive and it generally showed large framed body shape. The size of body was influenced mostly by chest depth(0.328<TEX>${\sim}$</TEX>0.339) and rump length(0.325<TEX>${\sim}$</TEX>0.341). The second, third and fourth principal component at the each period were various. There were positive correlations between principal components index of each period and carcass traits such as carcass weight(0.539<TEX>${\sim}$</TEX>0.755), average daily gain(0.256<TEX>${\sim}$</TEX>0.564), backfat thickness(0.227<TEX>${\sim}$</TEX>0.280), and eye muscle area(0.187<TEX>${\sim}$</TEX>0.344). The correlation with yield grade index(－0.246<TEX>${\sim}$</TEX>－0.110), however, was negative. The correlation with marbling score(0.066<TEX>${\sim}$</TEX>0.099) was low or statistically insignificant. According to principal component indexes of the second, third, and fourth components, the correlations with the carcass traits were various. There were no large differences between the correlations of the single body measurement trait with the carcass traits and the correlations of the first principal component indexes with the carcass traits.