• Journal of Animal Science and Technology
• /
• v.51 no.5
• /
• pp.345-352
• /
• 2009

This study utilized 332,625 records of linear type scores consisting for 15 primary traits, 22,175 final score and 84,612 pedigree information of 22,175 Holstein cows from 1993 to 2007 in Korea to estimate genetic parameters for 16 type traits. Genetic and error (co)variances between two traits selected from 16 traits were estimated using bi-trait pairwise analyses with DFREML package. The estimated heritabilities for stature (ST), strength (STR), body depth (BD), dairy form (DF), rump angle (RA), thurl width (TW), rear legs side view (RLSV), foot angle (FA), fore udder attachment (FUA), rear udder height (RUH), rear udder width (RUW), udder cleft (UC), udder depth (UD), front teat placement (FTP), front teat length (FTL) and final score (FS) were 0.31, 0.21, 0.25, 0.10, 0.29, 0.19, 0.09, 0.06, 0.12, 0.13, 0.12, 0.08, 0.26, 0.20, 0.28 and 0.15, respectively. ST had the highest positive genetic correlation with BD (0.90), while RLSV had the highest negative genetic correlation with FA (-0.56). RA had negative genetic correlation with most udder traits (-0.17~-0.02). Especially, RUW had the higher positive genetic correlation with STR (0.60), BD (0.62), and TW (0.49), however, UD had the higher negative genetic correlation with STR (-0.40) and BD (-0.40). FTL had negative genetic correlation with FUA, RUH, RUW, UC and UD. FS had positive genetic correlation with UC, UD and FTP (0.12, 0.18 and 0.20). However, additional research is needed on the use of these parameters in the genetic evaluation because estimated genetic and error variance-covariance matrices were not positive definite.

• Journal of Animal Science and Technology
• /
• v.50 no.3
• /
• pp.285-292
• /
• 2008

Data were taken from the dairy herd improve- ment program from the year 2000, composed of 10,929 first lactation cows consisting of 290,144 test-day records and 37,723 udder type records. The objective of the study was to estimate genetic and phenotypic correlation between fore udder attachment, rear udder height, rear udder width, udder cleft, udder depth, and somatic cell score (SCS) and to calculate heritability of udder depth, front teat length and SCS in Holstein cattle in Korea. The variance component estima- tion using test day model was determined by a derivative-free algorithm-restricted maximum likeli- hood(DF-REML) analysis method. Generally phenotypic correlations were very low between udder traits and lactation SCS which varied from －0.03 to －0.06. Heritability of all type traits and SCS was smaller than 0.12. The results of this study would be applicable to SCS using linear genetic evaluation for future studies.

• Journal of Animal Science and Technology
• /
• v.48 no.1
• /
• pp.15-20
• /
• 2006

The data used in the study were taken from the national dairy genetic evaluation of bulls from 1986 up to 2001. It was conducted to compare the phenotypic performance and genetic merits in terms of production traits, linear traits and selection indexes of four types of dairy semen (TypeⅠ:semen from Korean proven bull, Type Ⅱ:semen from proven bull imported by National Agricultural Cooperative Federation(NACF), Type Ⅲ:semen imported from USA, Type Ⅳ:semen imported from Canada) used in Korea. The result of national dairy genetic evaluation was used to compare genetic merits. Type Ⅲ was superior in the phenotypic performance of milk yield, milk fat and milk protein and was significantly different from Type Ⅰ. Types of semen were not significantly different in fat when semen from bull born after 1991 were compared. Likewise, types of semen were not significantly different in the genetic merit for milk yield, milk fat, milk protein and milk protein %. Moreso, for profit index (MFP) and Korean type production index (KTPI) it was not statistically different. However type Ⅰ was superior in milk fat % and was significantly different from other types. Type Ⅳ was superior in Final Score of conformation test (FS) and Udder Composite Index (UDC) and significantly different from Type Ⅰ. When semen from bull born after 1991 were compared, types of semen were not significantly different in milk yield and milk protein, although type I was superior in milk fat, milk fat %, milk protein % and MFP and was significantly different from others. Moreover type Ⅲ and type Ⅳ was superior in UDC and were significantly different from others.