• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.83-90
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• 1986

This study was conducted to determine the main effects of year, month, sire and parity on certain reproduction and lactation traits on the basis of the data obtained from 1,510 head of Holstein cows at National Animal Breeding Institute from 1971 to 1981. The results obtained in this study are summarized as follows; 1. The conception interval and number of services per concetption were 124.10 days and 2.19 times, respectively. The effects of year, month and sire on the above traits were significant. 2. The birth weight and gestation length were 42.20kg and 281.52 days, respectively. The effects of year, month and parity on the birth weight, and year, sire and parity on gestation length were significant. 3. The yields of milk and milk fat in 305 days, and the fat percent were 4937.05kg, 174.43kg and 3.56%, respectively. The effects of year, month, sire and parity on the above traits were significant. 4. The peak yield and days reaching the peak yield were 26.46kg and 49.17 days, respectively. The effects of the sire and parity on above traits were significant.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.441-444
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• 1998

The negative direct-maternal genetic correlation $(r_{dm})$ for weaning weight is inflated when data are analyzed with model ignoring sire-by-year interactions (SY). An analytical study investigating the consequences of ignoring SY was undertaken. The inflation of negative correlation could be due to a functional relationship of design matrices for additive direct and maternal genetic effects to that for sire effects within which SY effects were nested. It was proven that the maternal genetic variance was inflated by the amount of reduction for sire variance; the direct genetic variance was inflated by four times the change for maternal genetic variance; and the direct-maternal genetic covariance was deflated by twice the change for maternal genetic variance. The findings were agreed to the results in previous studies.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.225-234
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• 1993

A total of 333 carcasses were evaluated for hindquarter traits: round weight, percent round, loin weight, percent loin, flank weight and percent flank. Other characteristics included: total retail, lean trim, fat trim, round steaks, rump, sirloin tip, loin steaks, percent loin steaks and flank steaks. Mating types included straightbred Angus and Santa Gertrudis, the reciprocal crosses of these two breeds and Gelbvieh ${\times}$ Angus. Breed of sire and breed of dam were significant for most of the traits evaluated. Calf year and slaughter group were also significant. This could be the result of environmental variations. Effect of sire within sire breed was non-significant for all the traits considered. Heterosis due to interaction between sire breed ${\times}$ dam breed was found significant for percent total retail cuts based on hindquarter weight. Generally, Santa Gertrudis purebreds were more desirable in cut out characteristics than all other breeding types followed by crossbreds of Angus ${\times}$ Santa Gertrudis.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.227-230
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• 2001

To know and apply the factors affecting calf's gender may increase our competitiveness of Hanwoo industry. Thus, this study was carried out to analyse the effect of expected factors on calf's gender and to make an alternative idea for desired calf's gender. Gender of calves born by AI was not affected by AI year and cow parity, but significantly affected by sire and farm. Therefore, to obtain calves' gender that we want, both selecting optimum sire for AI and providing optimum feeding environment for cow should be required.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.9
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• pp.1387-1392
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• 2018

Objective: In a nucleus breeding scheme, the sire of dam's pathway plays an important role in producing genetic improvement. Selection proportion is the key parameter for predicting selection intensity, through truncating the normal distribution. Semen sexing using flow cytometry reduces the number of vials of sperm that can be obtained from a proved bull. In addition, a lower fertility of this kind of sperm is expected because of the lower sperm dosage in sex sorted semen. Both of these factors could affect the selection proportion in the sire of dam's pathway ($p_{SD}$). Methods: In the current study, through a deterministic simulation, effect of utilizing sex sorted semen on selection ($p_{SD}$) was investigated in three different strategies including 1: continuous use of sex sorted semen in heifers (CS), 2: the use of sex sorted semen for the first two (S2) and 3: the first (S1) inseminations followed by conventional semen. Results: Results indicated that the use of sex sorted semen has a negative impact on the sire of dams (SD) pathway due to increase in selection proportion. Consequently selection intensity was decreased by 10.24 to 20.57, 6.38 to 8.87 and 3.76 to 6.25 percent in the CS, S2, and S1 strategies, respectively. Conclusion: Considering the low effect of sexed semen on genetic improvement in dam pathways, it is necessary to consider the joint effect of using sex sorted semen on the sire and dams pathway to estimate about the real effect of sexed semen on genetic improvement in a nucleus breeding scheme.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.6
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• pp.729-732
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• 2000

Weight records from birth to calving and calving scores of 407 two-year old heifers and weights of their offspring from birth to one year of age were used to study the effects of sire birth weight on maternal traits of their female progeny. The heifers (G1) were the progeny of 81 sires (G0) and were classified into three classes based on their sires' birth weights (High, Medium and Low). The heifers were from three distinct breed-groups and were mated to bulls with medium birth weights within each breed-group to produce the second generation (G2). The data were analyzed using a covariance model. The female progeny of high birth-weight sires were heavier from birth to calving than those sired by medium and low birth-weight bulls. The effect of sire birth weight on calving difficulty scores of their female progeny was not significant. Grand progeny (G2) of low birth-weight sires were lighter at birth than those from high birth-weight sires (p<0.05) but they did not differ significantly in weaning and yearling weights with the other two Grand progeny groups. The results indicated that using low birth weight sires would not result in an increase in the incidence of dystocia among their female progeny calving at two-year of age and would not have an adverse effect on weaning and yearling weights of their grand progeny.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1523-1526
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• 2002

Genetic parameters of carcass weight (CWT), dressing percent (DP), cook loss (CL), eye muscle area (EMA), back fat thickness (BFT), and meat tenderness in terms of mastication (MAS), shear force (SFR) and penetration (PEN) in Korean native cattle were estimated in this study. Effects of sire, location and their interaction on these traits were also evaluated. Sire effects were found to be significant on all the traits studied except for PEN. The CWT and DP were also significantly affected both by location (p<0.01) and by interaction effect between sire${\times}$location (p<0.05). The EMA was significantly (p<0.05) affected by location but not by interaction effect between sire${\times}$location. All the traits were positively correlated ($r_g$ and $r_p$) with each other except between CL and meat tenderness (negatively correlated). Moderate to high genetic correlations between CWT and other important traits were obtained; indicating that selection for CWT would lead to improve carcass quality. Heritability estimates were 0.64, 0.52, 0.37, 0.25, 0.19 and 0.18 for MAS, SFR, CWT, PEN, DP and EMA, respectively.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.231-235
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• 2001

Gestation duration of cow is an important economical trait. Shortening the gestation duration decreases the production cost and increases the competitiveness of Hanwoo industry. Thus, this study was carried out to analyse the effect of expected factors on gestation duration and make an alternative idea for reduced gestation duration. Gestation duration was not affected by cow-parity, but significantly affected by farm, Al year and sire. Therefore, reducing the gestation duration of Hanwoo may require both providing optimum feeding environment and nutrition management for cow and selecting optimum sire for AI.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.10
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• pp.1351-1358
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• 2009

Parentage tests using polymorphic DNA marker are commonly performed to avoid incorrect recording of the parental information of livestock animals, and single-nucleotide polymorphisms (SNPs) are becoming the method of choice. In Japanese Black cattle, parentage tests based on the exclusion method using microsatellite markers are currently conducted; however, an alternative SNP system aimed at parentage tests has recently been developed. In the present study, two types of simulations were conducted using the pedigree data of two subpopulations in the breed (subpopulations of Hyogo and Shimane prefectures) in order to examine the effect of actual genetic and breeding structures. The first simulation (simulation 1) investigated the usefulness of SNPs for excluding a close relative of the true sire; the second one (simulation 2) investigated the accuracy of sire identification tests for multiple full-sib putative sires by a combined method of exclusion and paternity assignment based on the LOD score. The success rates of excluding a single fullsib and sire of the true sires were, respectively, 0.9915 and 0.9852 in Hyogo and 0.9848 and 0.9852 in Shimane, when 50 SNPs with minor allele frequency (MAF: q) of 0.25${\leq}$q${\leq}$0.35 were used in simulation 1. The success rates of sire identification tests based solely on the exclusion method were relatively low in simulation 2. However, assuming that 50 SNPs with MAF of 0.25${\leq}$q${\leq}$0.35 or 0.45${\leq}$q${\leq}$0.5 were available, the total success rates including achievements due to paternity assignment were, respectively, 0.9430 and 0.9681 in Hyogo and 0.8999 and 0.9399 for Shimane, even when each true sire was assumed to compete with 50 full-sibs.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.1
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• pp.1-5
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• 2003

Genetic parameters of live weight at slaughter (LWT), quantity index (QIX), yield grade (YGD), quality grade (QGD), pH of meat, and boiled meat tenderness in terms of mastication (BMAS), shear force (BSFR) and penetration (BPEN) in Hanwoo steers were estimated. Effects of sire, location and their interaction on these traits were also evaluated. Sire effects were found to be significant on all the traits studied except for pH and BSFR. The LWT, QIX and QGD were also significantly affected both by location and by interaction effect between sire${\times}$location. The BSFR and BPEN were significantly (p<0.01) affected by location but not significantly by sire${\times}$location interaction. The boiled meat tenderness and pH were negatively correlated ($r_g$ and $r_p$) with LWT, QIX and QGD. All the other traits were positively correlated with each other. Positive and high genetic correlation (+0.56) between LWT and QGD was obtained indicating that selection for LWT would improve QGD. The $h^2$ estimates were 0.43, 0.37, 0.37, 0.35 and 0.32 for QGD, LWT, pH, BSFR and BPEN, respectively.