A protein that binds the intracellular domain of the type 1 TNFR (TNFR-1IC) has been identified by two-hybrid cloning. The 97-kDa TNFR-associated protein, TRAP2, shows sequence identity with internal amino acid sequences from subunit 2 of the 26S protease. TRAP2 antiserum recognizes subunit 2 of the 26S protease, which is consistent with the identity of these proteins. TRAP2 antiserum interacted with the 97-kDa protein in HeLa cell lysates and cytosol, the latter observation showing that TRAP2 resides in the same cellular compartment as TNFR-1IC. A fusion of glutathione-S-transferase and TNFR-1IC (GST-TNFR-1IC) precipitated TRAP2 from a HeLa cell lysate; conversely, GST-TRAP2 precipitated TNFR-1 from such a lysate. These observations show that the proteins interact in the cellular milieu. After in vitro transcription/translation and 35S labeling, TRAP2 was precipitated from a cellfree system by GST-TNFR-1IC, showing that TNFR-1IC and TRAP2 interact directly. TRAP2 was also precipitated from the cellfree translation system by a GST fusion containing the N-terminal half of TNFR-1IC, but not by a GST fusion containing the C-terminal half of TNFR-1IC that contains a “death domain” that plays an obligatory role in signaling cytotoxicity. The ability of deletion mutants of TNFR-1IC to interact with TRAP2 was tested using the two-hybrid system. This also showed that the amino acid sequences that mediate binding reside outside of the death domain in TNFR-1IC. The demonstration that a subunit of the 26S protease binds TNFR-1 may identify a novel TNF-signaling pathway.

The Holstein breed is the mainstay of dairy production in Korea. In this study, we evaluated the genomic prediction accuracy for body conformation traits in Korean Holstein cattle, using a range of π levels (0.75, 0.90, 0.99, and 0.995) in Bayesian methods (BayesB and BayesC). Focusing on 24 traits, we analyzed the impact of different π levels on prediction accuracy. We observed a general increase in accuracy at higher levels for specific traits, with variations depending on the Bayesian method applied. Notably, the highest accuracy was achieved for rear teat angle when using deregressed estimated breeding values including parent average as a response variable. We further demonstrated that incorporating parent average into deregressed estimated breeding values enhances genomic prediction accuracy, showcasing the effectiveness of the model in integrating both offspring and parental genetic information. Additionally, we identified 18 significant window regions through genome-wide association studies, which are crucial for future fine mapping and discovery of causal mutations. These findings provide valuable insights into the efficiency of genomic selection for body conformation traits in Korean Holstein cattle and highlight the potential for advancements in the prediction accuracy using larger datasets and more sophisticated genomic models.

Objective: In Korea, dairy cattle breeding programs have historically prioritized productive, conformation traits, leading to positive improvements, yet reproductive traits have lagged in development. This study was conducted to develop the breeding program of key reproductive traits in the Korean dairy cattle population.Methods: Utilizing data from 7,596 farms and over seven million observations, we conducted quality control to rectify manual entry errors and selected traits in line with international genetic evaluation standards. Traits analyzed included heifer conception rate (HCR), interval from calving to first insemination (CF), cow conception rate (CCR), interval from first to last insemination (FL), and days open (DO). Genetic parameters were estimated using a single trait animal model for HCR and a multiple lactation animal model for CF, CCR, FL, and DO, considering contemporary group of herd-insemination year, insemination month, and monthly age as fixed effects.Results: Results showed low heritability estimates, ranging from 0.007 to 0.035 across different traits and lactations. Theoretical reliability appears to be low on average due to the influence of heritability, but it showed sufficiently high reliability in some sires (over 0.8). In terms of genetic and phenotypic trends, capacity for reproductive traits declined for a long time until around 2014. In recent individuals, improved trend can be found.Conclusion: This study addressed the critical need for enhancing reproductive efficiency to complement the existing breeding goals, thereby supporting sustained economic viability in the dairy industry. The results underscore the need for improved data quality and methodological adjustments for reproduction records to enhance the genetic evaluation of dairy cattle in Korea.

Objective: We investigated genetic parameters of calving ease (CE) using several animal models in Korean Holstein and searched for suitable models for routine evaluation of CE.Methods: Two phenotypic datasets of CE (DS5 and DS10) on first-parity Korean Holstein calves were prepared. DS5 and DS10 included at least 5 and 10 CE records per herd-year level and comprised 117,921 and 80,389 observations, respectively. The CE phenotypes ranged from 1 to 4, from a normal to extreme difficulty calving scale. The CE was defined as a trait of the calf. The BLUPF90+ software was used for (co)variances estimation through four animal models with a maternal effect (M1 to M4), where all models included effects of a fixed calf-sex, a fixed dam calving age (covariate), and one or more fixed contemporary group (CG) terms. The CG effects were different across models—a herd-year-season (M1, HYS), a herd-year and year-season (M2, HY+YS), a herd-year and season (M3, HY+S), and a herd and year-season (M4, H+YS).Results: Direct heritability (h2) estimates of CE ranged from 0.005 to 0.234 across models and datasets. Maternal h2 values were low (0.001 to 0.090). Genetic correlations between direct and maternal effects were strongly negative to lowly positive (–0.814 to 0.078), further emphasizing its importance in CE evaluation models. These genetic parameter estimates also indicate slower future selection progress of CE in Korean Holsteins. The M1 fitted many levels with fewer observations per level deriving unreliable parameters, and the M4 did not account for confounded herd and animal structures. The M2 and M3 were deemed more realistic for implementation, and they were better able to account for data structure issues (incompleteness and confounding) than other models.Conclusion: As the pioneering study to employ animal models in Korean Holstein CE evaluation, our findings hold significant potential for this breed's future and routine evaluation development.

Objective: This study analyzed the impact of age at first calving (AFC) on the reproduction and longevity of Hanwoo (Korean beef cattle) cows and proposed selection indices for genetic improvement of AFC. Methods: Data on the age at first calving, lifetime calving count, lifespan, and productive lifespan of 30,534 cows born between 2010 and 2023 and culled or sold at 280 farms of 4 cooperatives in the Chungnam region participating in the Hanwoo cow test project, as well as 49,723 calving interval data of these cows were used for analysis. Results: The most frequent AFC for Hanwoo cows was approximately 24 months (736 days). Reproductive efficiency was highest when AFC was close to 24 months, showing the shortest calving intervals. Superior performance in longevity and productive life was observed within the 22–25 month range of AFC. The heritability of AFC was 0.12, which was higher than that of the calving interval (0.08), indicating potential for genetic improvement through selection. Economic losses occurred if the age of first calving deviates from the appropriate age range. Conclusion: The study suggests selection index models that apply different economic weights based on 23 and 24 month split points of AFC data, where the genetic characteristics of AFC change significantly. In addition, each model assigns different economic weights for AFC according to the positive (+) and negative (−) values of the breeding value.

Objective: To investigate genetic correlation between calving ease (CE) and gestation length (GL) traits of Korean Holstein cattle to understand genetic structures of these two traits and their potential implications.Methods: Records of progenies from first parity (P1, N = 117,921) and second parity (P2, N = 141,104) Holsteins cows were used for analysis. All phenotypes (CE and GL) were considered as calf traits. The CE was an ordered categorical trait. It was scored from 1 (normal calving) to 4 (difficult calving). GL observations were restricted between 260 and 305 days. Variance components and genetic parameters were estimated through a bivariate animal model with a correlated maternal effect using the BLUPF90+ software package.Results: Heritability (h2) estimates of CE for direct and maternal effects were low (less than 0.01) in all parity calves. For GL, despite lower h2 of maternal effect (~0.03), the direct effect was moderately heritable (0.20 to 0.23) in this study. Direct and maternal effects of CE trait were weakly correlated (P1: 0.09±16.60, P2: −0.04±0.00). GL had similar correlation patterns (P1: 0.03±0.00; P2: −0.15±0.05) across parities. Direct genetic correlations of GL and CE were mostly weak (P1: 0.18±0.31; P2: −0.01±0.06), whereas maternal genetic correlations were moderate and positive (P1: 0.39±0.95; P2: 0.46±0.04). Although the genetic influence of GL on CE was not entirely clear due to large estimation errors for parameters, overall positive associations between direct effects and maternal effects essentially indicate a selection potential for GL as an indicator trait of CE.Conclusion: This is the first genetic correlation investigation of GL and CE in Korean Holstein cattle. It provides important insights into genetic architectures of GL and its future potential as an indicator trait for CE improvements in Korean Holsteins.