• Korean Journal of Poultry Science
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• v.22 no.2
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• pp.67-75
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• 1995

The present study was conducted to estimate production performances, heritabilities, and genetic and phenotypic correlations on several economic traits in Korean native chicken. Data analyzed were the records of 1,096 pullets produced from 180 dams and 26 sires of Korean native chicken from April 19,1994 to February 26, 1995. Results obtained are surnmarized as follows: 1. The body weights(X${\pm}$SD) at 2, 8, 14 and 20 weeks of age were 114${\pm}$13, 690${\pm}$114, 1,163${\pm}$238, and 1,687${\pm}$349g, respectively. The age at first egg was 165.95${\pm}$14.54 days, and the number of eggs produced by 300 days of age were 70.78i23.47. The egg weights of the first egg and at 300 days of age were 37.88${\pm}$3.73 and 50.97${\pm}$3.69 g, respectively. 2. The heritability estimates of body weight based on the variance of sires, dams and combined components were 0.149, 0.298, and 0.224 at 8 weeks of age: 0.162, 0.220, and 0.192 at 20 weeks of age, respectively. 3. The heritability estimates of egg production traits based on the variance of sires, dams, and combined components were 0.232, 0.504, and 0.368 for age at first egg; 0.113, 0.172, and 0.143 for number of egg production by 300 days of age: 0.174, 0.352, and 0.236 for egg weight at 300 days of age, respectively. 4. The genetic correlation coefficients of some economic traits were as follows: between body weight and age at first egg, -0.354~-0.048; between body weight and number of egg production, -0.279~ -0.002; between body weight and egg weight, 0.338~0.977; between age at first egg and number of egg production, -0.791; between age at first egg and egg weight, 0.009~0.178; between number of egg production and egg weight, -0.572~ -0.256, respectively. 5. The phenotypic correlation coefficients of some economic traits were as follows: between body weight and age at first egg, -0.179~-0.006 between body weight and number of egg production, -0.045~0.074: between body weight and egg weight, 0.229~0.404: between age at first egg and number of egg production, -0.588: between age at first egg and egg weight, -0.029~0.597: between number of egg production and egg weight, -0.376~0. 019, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.1
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• pp.11-15
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• 2002

The present investigation was undertaken to study the effects of non-genetic factors and association among replacement and lifetime production traits. The data on 542 Holstein Friesian cows maintained during 1975-98 at State Cattle Breeding Project, Sector III, Hisar, were utilized. The average sex-ratio, abnormal births, mortality, culling and replacement rates on total calf born and total female calf born basis were 51.62, 8.50, 17.52, 31.05, 22.78 and 51.41 per cent, respectively. The study revealed that a minimum of 4 to 5 progenies are required per cow over its lifetime to replace itself. It indicated that each cow should produce a minimum of 2 female calves during its life so as to replace herself before being lost. The least-squares means for productive herd life, longevity and lifetime production were $1439.32{\pm}87.64$ and $2419.18{\pm}8.25$ days and $11317.95{\pm}913.15kg$, respectively. The heritability estimates for all replacement traits were very low indicating that sire selection may bring no desirable change in these traits. Heritability estimates were $0.178{\pm}0.157$, $0.288{\pm}0.184$ and $0.096{\pm}0.195$ for corresponding lifetime production traits. Breeding values and ranking of sires were generated for replacement and lifetime production traits to estimate the rank correlations between these traits. Moderate desirable rank correlations were obtained between replacement rate and lifetime production traits indicating that sires proven on the basis of milk production are also expected to have better replacement rate.

• Journal of Animal Science and Technology
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• v.55 no.2
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• pp.81-85
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• 2013

This experiment was conducted to investigate the effects of lactation records in Holstein dairy cattle on the selection rates using a total of 341,436 test records from 113, 812 heads of cattle from first to third lactation. Heritabilities for milk, fat, and protein yields were highest at first lactation (0.28, 0.24, and 0.27, respectively), and decreased to 0.14, 0.15, and 0.13 at third lactation. For the milk yields, phenotypic correlations between first and second lactation, first and third lactation, and second and third lactation were low (0.49, 0.39, and 0.47, respectively), while genetic correlations among consecutive lactations and between second and third were above 0.8 and 0.9. In Model I, of the 1,138 heads the top 1% were selected based on first lactation records, only 32.4% (396 heads) were re-selected when the second lactation records were included and the 67.6% (769 heads) were newly selected animals. While in Model II, 85.1% (1,138 heads) of the animals which were selected as the top 1% on the basis of first and second lactation records were included. A multiple trait evaluation method using multiple lactation records is more desirable than a single trait evaluation method using first lactation records only.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1225-1233
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• 2017

Objective: Calving ease (CE) is a complex reproductive trait of economic importance in dairy cattle. This study was aimed to investigate the genetic merits of CE for Holsteins in Korea. Methods: A total of 297,614 field records of CE, from 2000 to 2015, from first parity Holstein heifers were recorded initially. After necessary data pruning such as age at first calving (18 to 42 mo), gestation length, and presence of sire information, final datasets for CE consisted of 147,526 and 132,080 records for service sire calving ease (SCE) and daughter calving ease (DCE) evaluations, respectively. The CE categories were ordered and scores ranged from CE1 to CE5 (CE1, easy; CE2, slight assistance; CE3, moderate assistance; CE4, difficult calving; CE5, extreme difficulty calving). A linear transformation of CE score was obtained on each category using Snell procedure, and a scaling factor was applied to attain the spread between 0 (CE5) and 100% (CE1). A sire-maternal grandsire model analysis was performed using ASREML 3.0 software package. Results: The estimated direct heritability ($h^2$) from SCE and DCE evaluations were $0.11{\pm}0.01$ and $0.08{\pm}0.01$, respectively. Maternal $h^2$ estimates were $0.05{\pm}0.02$ and $0.04{\pm}0.01$ from SCE and DCE approaches, respectively. Estimates of genetic correlations between direct and maternal genetic components were $-0.68{\pm}0.09$ (SCE) and $-0.71{\pm}0.09$ (DCE). The average direct genetic effect increased over time, whereas average maternal effect was low and consistent. The estimated direct predicted transmitting ability (PTA) was desirable and increasing over time, but the maternal PTA was undesirable and decreasing. Conclusion: The evidence on sufficient genetic variances in this study could reflect a possible selection improvement over time regarding ease of calving. It is expected that the estimated genetic parameters could be a valuable resource to formulate sire selection and breeding plans which would be directed towards the reduction of calving difficulty in Korean Holsteins.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1813-1821
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• 2002

The aim of this study was to identify useful secondary traits for estimating genetic ability of milk production traits. We investigated the value of using plasma metabolites concentrations. Two hundred and nineteen cattle out of 271 had only milk production traits records (G1), 33 had only metabolites records (G2), and 19 had both milk production traits and metabolites records (G3). Fifty two calves with metabolites records (G2 and G3) were born from 1992 to 1997. Forty three calves (29 females, 14 males) were used from 10 to 90 d of age and the others (3 females, 6 males) from 10 to 60 d of age. A total of 566 records of milk yield, fat yield and protein yield for 240 to 305 d on 238 heads (G1 and G2) were collected The collected blood samples were divided into three age groups: AG1, 10 to 30 d; AG2, 40 to 60 d; and AG3, 70 to 90 d. Heritabilities of milk yield, fat yield and protein yield were $0.45{\pm}0.04$, $0.50{\pm}0.04$ and $0.38{\pm}0.04$, respectively. Heritability of plasma glucose concentration at AG1 was $0.45{\pm}0.08$. Genetic correlations between plasma glucose concentration and milk yield, fat yield and protein yield were -$0.35{\pm}0.28$, $0.64{\pm}0.24$ and $0.36{\pm}0.35$, respectively. When the plasma glucose concentration at AG1 was used to estimate genetic ability of these milk production traits, reliability of milk yield of animals without milk record increased 8.2%, fat yield increased 24.2% and protein yield increased 9.5%. Heritability of plasma total cholesterol concentration at AG3 was $0.83{\pm}0.04$. Genetic correlation between plasma total cholesterol concentration and milk yield, fat yield and protein yield were $0.58{\pm}0.21$, $0.42{\pm}0.20$ and $0.45{\pm}0.22$, respectively. When the plasma total cholesterol concentration at AG3 was using to estimate genetic ability of these milk production traits, reliability of milk yield of animals without milk record increased 19.0%, fat yield increased 9.6%, and protein yield increased 13.5%. The annual genetic gain is in proportion to the reliability of selection. These results show that the plasma metabolite concentrations would be useful for improvement of genetic ability for milk production traits in the genetic improvement in herd of cows, where half of the animals selected are from a herd without its own milk record.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.12
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• pp.1609-1613
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• 2009

The objective of this study was to estimate genetic parameters for racing performance traits of thoroughbredracehorses, using a total of 58,124 racing records of 4,200 horses at Gwacheon Racing Park collected from January 2002 to December 2006. This study measured start one furlong time, last three and last one furlong times, and the resulting furlong time averages were 14.2 seconds, 39.9 seconds and 13.9 seconds, respectively. Furlong time means a split time measured based on a 1/8-mile (or approximately 201 m) distance and finished time means total racing time measured from start position to finish line. In the shortest distance races of 1,000 m, the average last three and last one furlong time was fastest at 38.7 seconds and 13.6 seconds, respectively. The correlation between finished time and start one furlong time decreased as the race distance increased, and the same trend was recognized from the correlation between finished time and last three furlong time. In short distance races of 1,400 m or less, the starting ability was found to be an important trait. The average speed was highest at 56 km/h for a 1,000 m race and lowest at 53.2 km/h for a 1,700 m race. Heritabilities of the start one furlong time, the last three and last one furlong time were estimated to be 0.337, 0.245 and 0.210, respectively; and repeatabilities for them were 0.452, 0.353 and 0.309, respectively. Phenotypic and genetic correlations between the start and the last one furlong time were negative at -0.141 and -0.155, respectively.

• Journal of Korean Society of Forest Science
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• v.84 no.3
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• pp.356-360
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• 1995

Korean white pine(Pinus koraiensis S.et Z.) is one of the important silvicultural species due to its quality timber in addition to edible pine - nut production. Selective breeding method is under progress to improve growth and nut production for this species. This study was carried out to obtain genetic information necessary for establishing advanced generation seed orchard, such as genetic parameters and efficiency of early selection. Open - pollinated cones were collected from 50 plus trees. In the spring of 1986, test plantations were established at 3 different sites with 4 - year - old seedlings. Seedling height was measured from age 5 to 10 in plantations. Genetic and phenotypic correlations based on the log of the ratio of two ages (LAK) were expressed as simple regression with statistical significance($r^2=0.7862$ and 0.8256, respectively). If 20 years is presumed to mature, the most efficient age for early selection is 3 years after planting with efficiency of 1.96.

• Korean Journal of Poultry Science
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• v.9 no.1
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• pp.35-42
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• 1982

Data pertaining to the first generation of a Synthetic White Leghorn flock were used to estimate the heritabilities of and genetic correlation between partial egg production(egg number or percentage) or diversely segmented part records and other traits such as age at sexual maturity, residual and annual egg production, and to compare the expected genetic gain from selection on partial egg number or partial percent production with correlated response in other traits. The estimated heritabilites for six measures of egg Production were ranged from 29 to 35, while heritability for age at sexual maturity (SM) was intermediate (48). Genetic correlations between partial egg number (P) and annual egg number. (A), and partial percent production (P') and annual percent production (A') were 51 and 72, respectively. Genetic correlation between P and SM was estimated largely negative (-.64), while correlation bettween P' and SM was positively intermediate(34). In comparing direct response from selection on partial production (P or P') with another response in correlated trait, selection on P would be 25% more efficient than selection of P' for improving A, while selection of P' would be 94% more efficient than selection P for improving A' For shortening SM selection of P would be 98% more efficient than selection on P'.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.2
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• pp.179-185
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• 1986

This study was to compare year variations of heritability, phenotypic, genotypic and environmental correlations as well as pathway coefficients for main characters of tea tree to provide useful selection information for improving tea tree. The data collected from the performance yield trials from 1979 to 1981 were used in this study. I. The genetic variance of fresh fruit yielding, dryed fruit yielding and fresh weight of root was not only greatly varied with year, but also the largest among all characteristies studied. Other characteristics showed higher genetic variance than environmental variances, and year variances were not large. 2. Both year and variety x year interaction were highly significant sources of variation for all yield characteristics, and year variances were not large. 3. All characteristics showed high broad sense heritabilities, and the broad sense heritability was not varied with year. 4. The genetic correlation coefficients between fresh fruit yielding and dryed fruit yielding, fresh weight of root and Gigolpi, dryed weight of root and Gigolpi were positive, and the year variation was not large. S. The pathway coefficients of the character was not only greatly varied with year and the fresh weight of root affected directly on the Gigolpi.

• Journal of Animal Science and Technology
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• v.63 no.6
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• pp.1211-1222
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• 2021

Data of 651 lambs (68 Romanov, 49 Rahmani, 151 [♀1/2 Rahmani × ♂1/2 Romanov) and 383 (♀3/4 Rahmani and 1/4♂ Romanov]) were collected from Mehalet Mousa Farm, belonging to Animal Production Research Institute from the period of 2009 to 2016 to estimate phenotypic and genetic parameters. The traits studied were birth weight (BW), body weight at four week (BW4), body weight at eight weeks (BW8) and body weight at twelve weeks (BW12) or weaning weight. Least squares analysis of variance shows significance of the effects of breed groups, gender of lambs, birth type; month of birth and year of birth on all traits studied. Rahmani lambs had heavier BW, BW4, BW8 and BW12 while Romanov lambs had the lowest ones. The first generation (♀1/2 Rhamani × ♂1/2 Romanov) had heavier body weights than Romanov and the second generation (♀3/4 Rahmani × ♂1/4 Roamnov). Gender of lambs had highly significant effect on body weights. Males were significantly (p < 0.01) heavier than females for all traits studied. Least square means of BW, BW4, BW8 and BW12 for single lambs were 2.69, 10.43, 13.53 and 16.10 kg, respectively. Least square means of BW, BW4, BW8 and BW12 for twin lambs were 2.50, 9.37, 12.5 and 15.16 kg, respectively, while least square means of BW, BW4, BW8 and BW12 for triple lambs were 2.09, 7.86, 10.83 and 13.67 kg, respectively. Estimates of direct heritability measured by single trait animal model were 0.14, 0.23, 0.25 and 0.26 for BW, BW4, BW8 and BW12, respectively, and the corresponding measured by multi trait animal model were 0.17, 0.24, 0.32 and 0.36 for the same traits, respectively. All genetic and phenotypic correlations among different traits studied are positive and significant.