• Animal Bioscience
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• v.36 no.1
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• pp.63-74
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• 2023

Objective: The objective of this study was to investigate the effects of feeding active dry yeast (ADY) and yeast culture (YC) on fecal bacterial community in finishing bulls fed high-concentrate diets in the same experimental environment. Methods: Forty-five healthy finishing cattle (Simmental×Chinese Luxi yellow bulls; 24 months; 505±29 kg) were randomly divided into three groups: i) CON group (control group, only fed basal diet), ii) ADY group (fed basal diet + active dry yeast), and iii) YC group (fed basal diet + yeast culture). At the end of the trial, nine rectum fecal samples were randomly selected from each group for bacterial DNA sequencing. Results: There was no difference among groups about alpha diversity indices (all p>0.05), including ACE, Chao 1, Shannon, and Simpson indices. Principal component analysis and non-metric multidimensional scaling analysis showed a high similarity among three groups. Compared with CON group, ADY and YC groups had greater relative abundance of c_Clostridia, o_Oscillospirales, and f_Oscillospiraceae, but lesser relative abundance of g_Megasphaera, and s_Megasphaera_elsdenii (all p<0.01). And, the relative abundances of p_Firmicutes (p = 0.03), s_Prevotella_sp (p = 0.03), o_Clostridiales (p<0.01), g_Clostridium (p<0.01), f_Caloramatoraceae (p<0.01), and f_Ruminococcaceae (p = 0.04) were increased in the ADY group. The PICRUSt2 prediction results showed that the metabolic pathways had no significant differences among groups (p>0.05). Besides, the relative abundance of c_Clostridia (r = 0.42), and f_Oscillospiraceae (r = 0.40) were positively correlated to average daily gain of finishing bulls (p<0.05). Conclusion: Both of ADY and YC had no effect on diversity of fecal bacteria in finishing bulls, but the supplementation of ADY and YC can improve the large intestinal function in finishing bulls by increasing the abundance of cellulolytic bacteria and altering the abundance of lactic acid-utilizing bacteria.

• Journal of Embryo Transfer
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• v.31 no.2
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• pp.109-116
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• 2016

The recovery of epididymal sperm in animals is considered as one of the important tools to preserve high value or endangered species. However, there are no appropriate castrating indicators such as months of age in bull, sperm morphology, and motility, particularly in young Korean native bull (Hanwoo). Therefore, this study aimed to investigate sperm number, morphology, and motility of sperm in the epididymis tail of young Hanwoo bulls at 8 and 15 months of age. After castration, epididymal tails were collected and minced with blades to recover sperm. In experiments 1 and 2, sperm number, morphology, and motility were examined. Total number of sperm and percentage of normal sperm from bulls at 8 months of age was lower than that of bulls at 15 months of age after collection (P<0.05). Percentage of abnormal head, tail, proximal cytoplasmic droplet, dead and damaged acrosome of sperm from bulls at 8 months of age were higher than those of bulls at 15 months of age (P<0.05). In experiment 3, sperm motility from bulls at 8 and 15 months of age were examined before freezing and after thawing. Frozen-thawed sperm at 8 months of age showed low total motility and motile sperm with ${\geq}25{\mu}m/sec$ compared to those at 15 months of age and commercially-used sperm (P<0.05). In conclusion, sperm derived from the epididymal tail of bulls at 8 months of age showed high abnormal morphology and poor motility, which are not adequate for AI and IVF. On the other hand, sperm derived from the epididymal tail of bulls at 15 months of age showed high normal morphology and motility.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.450-455
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• 2010

The study had two objectives, namely, to estimate the andrological disorders leading to disposal of Karan Fries (KF), Sahiwal cattle and Murrah buffalo bulls and to study the effect of various factors (species/breeds, season of birth and period of birth) on male reproductive parameters. Records on occurrence of subfertility problems and disposal pattern of bulls maintained at the National Dairy Research Institute herd were collected for 15 years (1991 to 2005). Percentage of bulls producing freezable semen was less in the crossbred cattle (58.46%) as compared to Sahiwal (81.69%) and Murrah bulls (81.05%). Various subfertility traits like poor libido and unacceptable seminal profile were found to be the significant reasons (p<0.01) for culling of the breeding bulls. Inadequate sex drive was the main contributing factor for bull disposal in Sahiwal (22.55%) and Murrah bulls (15.12%) whereas poor semen quality and freezability were most frequently observed in KF bulls (24.29 and 7.29 percent, respectively). Least squares analyses of different male reproductive parameters showed that species/breeds had significant effect (p<0.05) on all traits except for frozen semen production periods (FSPP). Periods of birth were significantly different (p<0.05) for all traits except for semen volume. Age at first semen collection (AFSC), age at first semen freezing (AFSF) and age at disposal (AD) were highest in Murrah, while frozen semen production period (FSPP) and semen production period (SPP) were highest in KF and lowest in Sahiwal. The age at first semen donation and breeding period could be reduced by introducing the bulls to training at an early age. These results revealed a declining trend in AFSC, AFSF, FSPP, SPP and AD, thereby indicating an improvement in reproductive performance over the years. The age at first semen donation in bovines can be reduced by introducing the young male calves to training at an early age, which could increase the dosage of semen obtained from each male.

• Journal of Embryo Transfer
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• v.27 no.1
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• pp.29-35
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• 2012

The purpose of this study was to examine the effect of growing stages of the Korean Native Striped Bull (KNSB) on the freezability and fertility of frozen-thawed semen. First, we investigated the total motility (TM) and progressive motility (PM) according to the diluent used for semen freezing. Second, we examined the effect of the age of KNSB on semen volume, TM and PM of fresh and frozen-thawed semen. Third, we examined the effect of frozen semen from the different age of KNSB on the $in-vitro$ fertilization rate, and the artificial insemination pregnancy rate. The diluents used in this experiment were Triladyl$^{(R)}$ and Tris-egg yolk extender (EYE). Semen was collected from 5 KNSB in the growing stage (15 months) and 5 adult KNSB (36 months). When Triladyl or Tris-EYE extender was used for semen freezing, there was no difference of the mean TM and the mean PM. However, the mean TM was significantly higher in Bull No. 1885 than Bull No. 4283 ($p$ <0.05). The mean volume of semen collected from the 15-month-old bulls (2.3 ml) was significantly lower ($p$ <0.05) than that from the 36-month-old bulls (5.0 ml). The mean semen concentration was similar for the 15-month-old ($2.1{\times}10^9$ spermatozoa/ml) and 36-month-old ($1.8{\times}10^9$ spermatozoa/ml) bulls. For the 15-month-old and 36-month-old bulls, the mean TM of fresh semen were 93.7% and 88.3%, respectively, and the mean PM were 97.0% and 88.3%, respectively; the 15-month-old bulls showed a particularly high PM ($p$ <0.05). For the 15-month-old and 36-month-old bulls, the mean TM (56.0% and 58.0%, respectively) and the mean PM (64.0% and 70.7%, respectively) of frozen-thawed semen did not differ. The development rates of embryos after $in-vitro$ fertilization and the pregnancy rate after artificial insemination using frozen-thawed semen did not differ according to the bull's age. In summary, semen volume differed according to the bull's age, but semen concentration and survival rate, the $in-vitro$ fertilization rate, and the pregnancy rate did not differ according to the stripe bull's age. Accordingly, semen from bulls in the growing stage can be collected and frozen for the preservation and multiplication of rare livestock.

• Animal Bioscience
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• v.34 no.12
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• pp.1879-1885
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• 2021

Objective: Owing to the lack of a breeding index for efficient and quick fertility evaluations of Holstein bulls when using traditional or genome-wide detection methods, this study aimed to determine whether in vitro fertilization (IVF) could be used as an indicator of conception rate of artificial insemination (AI). Methods: Conventional and sexed frozen semen from nine bulls were used for IVF and AI. Results: The IVF and AI conception rates of each bull were confirmed to be positively correlated between the conventional frozen and sexed frozen semen. The correlation coefficient R values of nine bulls between IVF and AI methods were 0.73 and 0.97 for the conventional frozen and sexed frozen semen, respectively. The average conception rate of three bulls undergoing AI was 69.5% and 64.2%, 61.8% and 58.8%, and 48.2% and 46.2% in first-, second-, and third-born cows when conventional frozen and sexed frozen semen were used, respectively, which showed a positive correlation with the fertilization rate in the same parity. We propose an evaluation standard to assess the fertilization ability of bulls based on their IVF test results, which is categorized into three grades: grade one, normal fertility bull with an AI conception rate of 40%±5% and IVF rate of 45% to 60%; grade two, higher fertility bull with an AI conception rate of 50%±5% and IVF rate of 61% to 80%; and grade three, highest fertility bull with an AI conception rate of 60%±5% and IVF rate of >80%. Conclusion: These findings reveal that IVF results can be used as a breeding index for bulls to evaluate their AI conception ability, which may shorten the time required to select bulls for breeding.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.11
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• pp.1445-1454
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• 2010

Two separate animal trials were conducted to evaluate the coincidence of dry matter intake (DMI) and average daily gain (ADG) predicted by the Cornell Net Carbohydrate and Protein System (CNCPS) and observed actually in crossbred growing bulls kept in a traditionally confined feeding system in China. In Trial 1, 45 growing Simmental${\times}$Mongolia crossbred F1 bulls were assigned to three treatments (T1-3) with 15 animals in each treatment. Trial 2 was conducted with 60 Limousin${\times}$Fuzhou crossbred F2 bulls allocated to 4 treatments (t1-4). All of the animals were confined in individual stalls. DMI and ADG for each bull were measured as a mean of each treatment. All of the data about animals, environment, management and feeds required by the CNCPS model were collected, and model predictions were generated for animals on each treatment. Subsequently, model-predicted DMI and ADG were compared with the actually recorded results. In the three treatments in Trial 1, 93.3, 80.0 and 73.3% of points fell within the range from -0.4 to 0.4 kg/d for DMI mean bias; similarly, in the four treatments in Trial 2, about 86.7, 73.3, 73.3 and 80.0% of points fell within the same range. These results indicate that the CNCPS model can accurately predict DMI of crossbred bulls in the traditionally confined feeding system in China. There were no significant differences between predicted and observed ADG for T1 (p = 0.06) and T2 (p = 0.09) in Trial 1, and for t1 (p = 0.07), t2 (p = 0.14) and t4 (p = 0.83) in Trial 2. However, significant differences between predicted and observed ADG values were observed for T3 in Trial 1 (p<0.01) and for t3 in Trial 2 (p = 0.04). By regression analysis, a statistically different value of intercept from zero for the regression equation of DMI (p<0.01) or an identical value of ADG (p = 0.06) were obtained, whereas the slopes were significantly different (p<0.01) from unity for both DMI and ADG. Additionally, small root mean square error (RMSE) values were obtained for the unbiased estimator of the two variances (DMI and ADG). Thus, the present results indicated that the CNCPS model can give acceptable estimates of DMI and ADG of crossbred growing bulls kept in a traditionally confined feeding system in China.

• Journal of Animal Science and Technology
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• v.44 no.3
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• pp.341-350
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• 2002

Twenty four Hanwoo bulls(mean initial body weight 162$\pm$8.1kg) were employed to induce the regression equations on body weight gain and dry matter intake. The diets were fed in a 3${\times}$4 factorial arrangement; three roughage sources(rice straw, hay, corn silage) and four roughage ratios in ration(100, 60, 40, 20%). Bulls were alloted by incomplete turn over design with four replications. Daily body weight gain was greatest in bulls fed the corn silage as a roughage source and the 20% of roughage ratio, respectively. Bulls fed hay or corn silage only as feed kept in their body weight gain during the whole experimental period, however those fed rice straw only were in a negative body gain hereafter fatteningⅠperiod(350kg of body wt.). Dry matter intake per metabolizable body weight was decreased with increasing body weight. Dry matter intake was greatest in bulls fed the corn silage as a roughage source and the 20% of roughage ratio, respectively. The regression equations on daily body weight gain(DG, kg) and dry matter intake(DMI, kg/day) according to body weight(BW, kg) of Hanwoo bulls were derived as follows; DG = －0.842 + 17.5DMI/$BWkg^{0.75}$ DMI = 4.125 + 0.013BW + 1.075DG － 0.045NDF where, NDF is the percentage of neutral detergent fiber in ration.

• Journal of Animal Science and Technology
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• v.44 no.3
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• pp.279-288
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• 2002

This study was performed to discriminate defective loci by detection of congenital genetic disorder, to offer basic data for selection and improvement of Korean dairy cattle using frozen semen of Holstein bulls(16 proven and 93 candidate). The results obtained were as follows ; By the detection of DUMP(deficiency of uridine monophophate synthase) for 109 Holstein bulls(16 proven and 93 candidate), DUMP carrier was not found in whole animals. Also, it was possible to early detection of DUMP carrier by using PCR-RFLP(AvaⅠ). As the results of detection for BLAD(bovine leukocyte adhesion deficiency), BLAD carrier was not found in 16 proven bulls. But 5 candidtae bulls are discriminated to BLAD carrier, and it could be predicted to transmitted pathway of inherited loci by pedigree identification. Also, when digesting PCR products using restriction enzyme, results from TaqⅠ restriction enzyme were more efficient than that of HaeⅢ. After detection test of citrullinaemia, it was concluded that proven and candidate bulls were not. However, wide range of research and citrullinaemia genotyping should be performed. As a result of this study, the wide and various research should be performed in genetic disease of animal. And in the selection and breeding of animal, the breeding scheme by completely and continuously management of pedigree should be established.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.3
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• pp.382-389
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• 2020

Objective: This study was conducted to test the efficiency of genomic selection for milk production traits in a Korean Holstein cattle population. Methods: A total of 506,481 milk production records from 293,855 animals (2,090 heads with single nucleotide polymorphism information) were used to estimate breeding value by single step best linear unbiased prediction. Results: The heritability estimates for milk, fat, and protein yields in the first parity were 0.28, 0.26, and 0.23, respectively. As the parity increased, the heritability decreased for all milk production traits. The estimated generation intervals of sire for the production of bulls (L_SB) and that for the production of cows (L_SC) were 7.9 and 8.1 years, respectively, and the estimated generation intervals of dams for the production of bulls (L_DB) and cows (L_DC) were 4.9 and 4.2 years, respectively. In the overall data set, the reliability of genomic estimated breeding value (GEBV) increased by 9% on average over that of estimated breeding value (EBV), and increased by 7% in cows with test records, about 4% in bulls with progeny records, and 13% in heifers without test records. The difference in the reliability between GEBV and EBV was especially significant for the data from young bulls, i.e. 17% on average for milk (39% vs 22%), fat (39% vs 22%), and protein (37% vs 22%) yields, respectively. When selected for the milk yield using GEBV, the genetic gain increased about 7.1% over the gain with the EBV in the cows with test records, and by 2.9% in bulls with progeny records, while the genetic gain increased by about 24.2% in heifers without test records and by 35% in young bulls without progeny records. Conclusion: More genetic gains can be expected through the use of GEBV than EBV, and genomic selection was more effective in the selection of young bulls and heifers without test records.

• Journal of Animal Science and Technology
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• v.44 no.6
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• pp.693-700
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• 2002

The objects of this study were to estimate gene frequencies of the bovine growth hormone(bGH), and to investigate the relationship between the bGH polymorphism and semen characteristics in Hanwoo bull. One hundred nine heads of Hanwoo bulls were used to identify bGH genotypes by the PCR-RFLP, followed by digestion with Alu I restriction enzyme. The frequencies of leucine(Leu) and Valine(Val) alleles were 0.88 and 0.12, respectively. Observed number of LL, LV and VV genotypes were 83, 25 and 1, respectively. Semen characteristics(semen volume, sperm concentration) were analyzed by GH genotypes in 25,559 ejaculates of 109 heads. Although bGH genotypes showed no significant effects on semen characteristics, those of bulls with VV genotype were tended to be lower than those of other bulls with LL or LV genotypes. And, in 1998, total sperm number(60.47${\times}$$10^8$) of VV bulls were significantly lower(P<0.05) than those(86.21${\sim}$92.22${\times}$$10^8$) of other genotypes bulls. This results provide that the VV bull in bGH locus may be worse, under the LL and LV bulls on semen characteristics. However, the number of examined VV bulls was only one and further investigations are needed to confirm the results.