• Journal of Animal Science and Technology
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• v.55 no.1
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• pp.1-6
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• 2013

This study was aimed to solve the problems of current national genetic evaluation systems in Korea and its development to pass the verification processes as required by International Bull Evaluation Service (Interbull). This will enable Korea to participate in international genetic evaluation program. A total of 1,416,589 test-day milk records with calving dates used in this study were collected by National Agricultural Cooperative Federation from 2001 to 2009. Parity was limited up to fifth calving and milk production records were adjusted to cumulative 305 day lactation. The pedigree consisted of 2,279,741 animals where 2,467 bulls had 535,409 parents. A newly developed multiple trait model was used in calculation of breeding values for milk yield, milk fat, and protein yield. Data were edited with SAS (version 9.2) and R programs, and genetic parameters were estimated using VCE 6.0. Results showed a continuous increase in genetic potentials, in general, and no remarkable differences were found between performances by parity. Except fat yield, potentials in milk yield and protein yield were well calculated. We found an increased number of daughters per each top ranked 1,000 bulls in recent years of calf births compared to the cases of previous evaluations. Of the bulls ranked top 100 by our new models (multiple-trait models) we found that increased numbers of bulls were included. Of twenty eight bulls born in 2006, twenty bulls born in 2007 and eight bulls born in 2008 that were listed by new models, only 23, 12, and 2 bulls born in respective years were represented on top 100 by old single-trait models. Re-ranking of the daughters or sires by multiple-trait models suggest that this new multiple trait approach should be used for dairy cattle genetic evaluation and seed-stock selection in the future to increase the accuracy of multiple trait selection. Breeding values for these traits should also be calculated by new method for international genetic evaluation.

• Journal of Animal Science and Technology
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• v.55 no.5
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• pp.373-380
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• 2013

The study aimed to develop prediction models of primal cut yield using body measurements of Hanwoo steers in Korea. The progeny of 874 steers at Hanwoo Improvement Main Center from 2008 to 2010 were recorded. Pearson's correlation coefficients for primal cuts and other traits were estimated. Primal cuts were adjusted for slaughter date and age using the SAS GLM procedure. Afterwards, a stepwise regression was performed on each primal cut by fitting body measurement traits. An independent covariable was selected at the highest coefficient of determination with the greater fitness model using Mallows's Cp statistic. Results showed that primal cuts were significantly influenced by slaughter date (P<0.01). The age at slaughter, however, was only significant for the top round (P<0.05). There was a moderate to high correlation between chest girth and tenderloin (0.54), loin (0.74), and rib (0.80). Most primal cut percentages were negatively related to BFT. Similar negative to low positive correlations were observed for primal cut percentage and body size traits. In addition, a correlation of 0.21 was observed between rib percentage and chest girth. The regression of body measurements on the adjusted primal cuts were significant for later traits. Regression estimates revealed that wither height, body length, rump length, hip bone width, and chest girth are important for primal cut weight and percentage determination. In particular, chest girth was always important for primal cut weight estimates.

• Journal of Animal Science and Technology
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• v.54 no.5
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• pp.317-321
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• 2012

This study was conducted to identify the characteristics and estimate the genetic parameters of average daily gain (ADG) and carcass traits of Hanwoo. The data used in this study were 4,681 heads which were performance-tested and 4,442 heads which were progeny-tested in test station of National Agricultural Cooperative Federation. The means and standard deviations of ADG between 6~9 months (ADG:6-9), ADG between 9~12 (ADG:9-12) and ADG between 6~12 (ADG:6-12) from the performance test were $1.04{\pm}0.16$, $1.11{\pm}0.17$ and $1.07{\pm}0.11$, respectively. The phenotypic correlations of ADG:6-9 and ADG:9-12, ADG:6-9 and ADG:6-12, ADG:9-12 and ADG:6-12 were -0.03, 0.66 and 0.65, respectively. The phenotypic correlations of ADG:6-12 with carcass weight (CW), eye muscle area (EMA), backfat thickness (BF), and marbling score (MS) from progeny test were 0.446, 0.199, 0.0266 and 0.045, respectively. Estimated heritabilities from the pooled data were 0.251 (ADG:6-12), 0.298 (CW), 0.424 (EMA), 0.503 (BF) and 0.626 (MS), respectively. Estimated genetic correlations of ADG:6-12 with CW, EMA, BF, MS were 0.606, 0.292, -0.095 and -0.007, respectively. From these results, it could be suggested that selection for ADG significantly affects CW, EMA and BF by correlated response to selection.