• Journal of Animal Science and Technology
• /
• v.66 no.5
• /
• pp.920-935
• /
• 2024

Embryo transfer plays a crucial role in enhancing the breeding value of livestock; it has been applied in Hanwoo cattle, which is a popular breed for beef production in Korea. Both in vivo-derived (IVD) and in vitro-produced (IVP) embryos are used for this purpose; however, IVP embryos have been preferred recently owing to advancements in ovum pick-up (OPU) technology and genomic selection. Despite technological advancements, comprehensive data on large-scale OPU/IVEP/embryo transfer in Hanwoo cows are lacking. In this study, 16 elite Hanwoo donor cows were selected on the basis of specific criteria. Oocytes were retrieved from 241 cows using OPU. The collected cumulus-oocyte complexes (COCs) were matured, fertilized, and cultured in vitro to produce transferable embryos. Embryos were classified according to their developmental stage and then transferred to 675 recipient cows. A total of 3,317 COCs were collected, with an average of 13.76 COCs per cow. The number of transferable embryos produced per cow was 3.7. Hanwoo OPU-derived IVP embryos exhibited a higher production yield than the global average, indicating a stable IVEP environment. Both fresh and frozen IVP embryos yielded similar conception rates; hence, the use of vitrified-thawed embryos in transfer plans feasible. However, frozen-thawed embryos at Stage 7 had a lower conception rate than those at earlier stages. There was no significant difference between the conception rates of sexually mature heifers and postpartum cows used as recipients. The male-to-female offspring ratio increased as the developmental stage progressed. Seasonal effects on conception rates were not observed; however, higher abortion rates and a higher proportion of male offspring were observed during winter. This study provides valuable data for the Korean embryo transfer industry, enabling more strategic growth of the domestic Hanwoo embryo industry.

• Korean Journal of Agricultural Science
• /
• v.43 no.2
• /
• pp.232-239
• /
• 2016

Recently, research has been focusing on high quality and safer animal production by utilizing natural functional materials. The aim of this study was to evaluate the effect of administration of natural Evening Primrose Oil (EPO) on gamma linolenic acid (GLA) levels in milk from Holstein dairy cows. Quality and quantity of milk as well as blood and fatty acids from Holstein cow fed diets supplemented with 2.7-4% calcium-salted EPO coated with palm stearin oil were analyzed. There was no significant difference in yield and composition of milk between control and EPO treatment. However, EPO treatment lowered blood aspartate aminotransferase (AST), somatic cell count (SCC), and cholesterol levels (p < 0.05) compared to untreated control. Blood urea nitrogen (BUN) level was decreased (p < 0.05) in GLA 1 and GLA 2 group when compared with control group. Non-esterified fatty acids (NEFA) concentration was lower (p < 0.05) in GLA 1 and GLA 2 groups than in control group. The level of GLA in milk was increased in EPO group when compared to control. Therefore, results from the present study demonstrate that supplementary EPO has beneficial effects on cow health, showing a decrease in somatic cell count and levels of blood cholesterol, alanine aminotransferase (ALT), and AST. Furthermore, supplementation of EPO improves milk quality with increased amounts of GLA.

• Food Science of Animal Resources
• /
• v.33 no.6
• /
• pp.708-714
• /
• 2013

This study was performed to investigate the influence of age on the physicochemical properties of strip loin (m. longissimus lumborum), chuck tender (m. supraspinatus), and eye of round (m. semitendinosus) of Hanwoo cows. Hanwoo cows (n=126; 24-194 mon; live weight, 270-500 kg) were slaughtered and three muscles were obtained according to 3 age groups (G1, < 5 years old; G2, 6-8 years old; G3, > 9 years old). The chuck tender had significantly higher protein contents in G3 than in G1 or G2 (p<0.05). For strip loin and chuck tender, G1 had significantly higher intramuscular fat contents than G3 (p<0.05). The chuck tender had significantly higher $b^*$ (yellowness) values for G2 than for G1 (p<0.05). The three muscles had significantly higher cooking loss (%) and lower WHC (%) in G3 than in G1 or G2 (p<0.05). WBS values of strip loin were significantly higher in G3 than in the other groups (p<0.05). The three muscles had higher C18:1n9 in G1 than that in the other groups. The total content of saturated fatty acids was significantly higher in G3 than in G1 for all 3 muscles (p<0.05). Regarding free amino acid contents, G1 had significantly higher contents of threonine, alanine, valine, methionine, phenylalanine, leucine, and lysine in the strip loin than G2 or G3 (p<0.05). In conclusion, young cow beef were higher in the WHC, intramuscular fat and free amino acids contents, whereas old cow beef had higher cooking loss and WBS (p<0.05).

• Food Science of Animal Resources
• /
• v.28 no.1
• /
• pp.45-50
• /
• 2008

This study was conducted to investigate the effect of different maturity scores [2 (bull), 2 (steer), 3-9 (cow)] and the number of extractions on water extract from Hanwoo shank bones (arm, fore shank, round and hind shank) with regard to sensory traits (white color, aroma, taste, overall acceptability). The white color of water extract from Hanwoo shank bones of maturity score 2 (bull and steer) was lighter than with maturity scores of 3-9 (cow) (p<0.05). The aroma of water extract from Hanwoo shank bones of maturity score 2 (bull and steer) was stronger than with other maturity scores 3-9 (cow) except for maturity score 5 (p<0.05). The taste and overall acceptability of water extract from Hanwoo shank bones of maturity score 2 (bull and steer) were higher than with maturity scores of 3-9 (cow) (p<0.05). The white color, aroma, taste and overall acceptability of water extract from Hanwoo shank bones of all maturity scores significantly decreased as the number of extractions (from 2nd to 4th) increased (p<0.05). In conclusion, there were significant differences between maturity scores 2 and maturity scores 3-9 (cow) with regard to sensory traits. Further studies need to address whether different maturity scores affect the price of shank bones in the meat industry.

• Journal of Animal Science and Technology
• /
• v.62 no.4
• /
• pp.449-459
• /
• 2020

Here, we investigated the effects of different nutrient requirements (NR) on blood metabolites, transferable embryo number after multiple superovulations with artificial insemination (AI), body condition score (BCS), and estrus cycle in Hanwoo cow. Nineteen Hanwoo cows were randomly divided into three groups (80%, 100%, and 120% NR, containing 6, 8, and 5 individuals, respectively) and fed based on the NR. In experiment 1, glucose, total cholesterol, triglyceride, blood urea nitrogen (BUN), aspartate aminotransferase (AST), alanine aminotransferase (ALT), non-esterified fatty acids (NEFA), albumin (ALB), and total protein (TP) were analyzed. In experiment 2, total number of recovered embryos and transferable embryos was examined after embryo recovery and multiple superovulations with AI. In experiment 3, body weight, BCS, and estrus cycle were examined. In experiment 1, total cholesterol was significantly different among the 80%, 100%, and 120% NR groups (126.5 ± 3.3, 152.6 ± 2.4, and 177.4 ± 1.8 mg/dL, respectively, p < 0.05). The triglyceride and BUN levels in the 120% NR group were significantly higher than those in the 80% and 100% groups (p < 0.05). The NEFA levels were significantly different among the 80%, 100%, and 120% NR groups (440.5 ± 18.2, 318.5 ± 23.1, and 195.1 ± 8.5 ЧEq/L, respectively, p < 0.05). The AST and TP levels in the 80% NR group were significantly lower than those in the 100% and 120% NR groups (p < 0.05). In experiment 2, the 120% NR group showed a higher percentage of transferable embryos than the 80% and 100% groups (p < 0.01). The mean body weight and BCS among the 80%, 100%, and 120% NR groups were significantly different (p < 0.05). The estrus cycle in the 80% NR group was delayed compared with the 100% and 120% NR groups (20.8 ± 0.2 and 21.2 ± 0.5 days, respectively). In conclusion, the blood metabolic tests proved that Hanwoo cows with 120% NR can produce a large number of transferable embryos. Thus, 120% NR is the appropriate feeding level for this type of cows as it results in the production of a large number of transferable embryos by multiple superovulations with AI.

• Korean Journal of Veterinary Service
• /
• v.43 no.2
• /
• pp.45-52
• /
• 2020

A grading system is implemented to evaluate the meat quality of Hanwoo. In the grading system, grade 1++A is the highest grade. Livestock farms breed Hanwoo with good quality feed in order to obtain the highest grade. In this process, the content ratios of muscles in individual regions can be changed. To find out the muscle distribution ratios of Hanwoo steers, grade 1A, 1+A, and 1++A Hanwoo steers were compared with grade 1+A Hanwoo female. Grade 1A Hanwoo steers had higher ratios of shank (SK), brisket and flank (BF), neck chain (NC), and inside skirt (IS) meats and a lower ratio of striploin (SL) meat compared to grade 1+A Hanwoo feamle. Grade 1++A Hanwoo steers had higher ratios of neck (NK) and loin (LN) meats and lower ratios of inside skirt (IS), tenderloin (TL), top round (TR), eye round (ER), bottom round (BR), bottom sirloin triangle (BST), and knuckle (K) meats compared to grade 1+A Hanwoo steers. In comparison between grade 1A and 1++A Hanwoo steers, the ratio of shank (SK) was significantly lower in higher quality meats. If the changes are continuously studied to improve the process so that the ratios of partial meats of the regions highly preferred by consumers can increase, it will contribute to increases in the incomes of livestock farms and enable Hanwoo to grow into a global brand.

• Journal of Embryo Transfer
• /
• v.21 no.2
• /
• pp.95-100
• /
• 2006

Thirty heads of proven bulls were used to identify the effects of mounting conditions (dummy cow vs. teaser bull) on semen characteristics in Hanwoo. Semen was collected from bulls daily two times with 1 h interval every $3{\sim}6$ days for 6 months. Bulls mounted dummy cow (BDC) had higher both the $1^{st}$ and the $2^{nd}$ sperm concentrations than in bulls mounted teaser bull (BTB), resulting in more total sperm number (p<0.05). The total sperm number in the $1^{st}$ collection was the highest in BDC with collection interval of 5 days. Total sperm number in the $1^{st}\;and\;2^{nd}$ collections tended to be more in the BDC of $4{\sim}5$ years old and BTB of $6{\sim}7$ years old. These results indicate that semen collection using dummy cow has a better effect than teaser bull on semen characteristics.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.2
• /
• pp.155-160
• /
• 2014

The purpose of this study was to estimate genetic parameters of ultrasound measurements for longissimus dorsi muscle area (LMA), backfat thickness (BFT), and marbling score (MS) in Hanwoo cows (N = 3,062) at the ages between 18 and 42 months. Data were collected from 100 Hanwoo breeding farms in Gyeongbuk province, Korea, in 2007 and 2008. The cows were classified into four different age groups, i.e. 18 to 22 months (the first pregnancy period), 23 to 27 (the first parturition), 28 to 32 (the second pregnancy), and 33 to 42 (the second parturition), respectively. For each age group, a multi-trait animal model was used to estimate variance components and heritabilities of the three traits. The averages of LMA, BFT, and MS measurements across the cows of all age groups were 50.1 $cm^2$, 4.62 mm, and 3.04, respectively and heritability estimates were 0.09, 0.10, and 0.08 for the respective traits. However, when the data were analyzed in different age groups, heritability estimates of LMA and BFT were 0.24 and 0.47, respectively, for the cows of 18 to 22 months of age, and 0.21 for MS in the 28 to 32 months old cows. When the cows of all age groups were used, the estimates of genetic (phenotypic) correlations were 0.43 (0.35), -0.06 (0.34) and 0.21 (0.32) between LMA and BFT, LMA and MS, and BFT and MS, respectively. However, in the cow age group between 28 and 32 (18 and 22) months, the estimates of genetic (phenotypic) correlations were 0.05 (0.29), -0.15 (0.24) and 0.38 (0.24), for the respective pairs of traits. These results suggest that genetic, environmental, and phenotypic variations differ depending on cow age, such that care must be taken when ultrasound measurements are applied to selection of cows for meat quality.

• Journal of Embryo Transfer
• /
• v.31 no.3
• /
• pp.273-279
• /
• 2016

The Korean native cattle, Hanwoo, is the most popular breed of beef cattle in Korea. However, the reproductive performance data are limited although reproduction is one of the most economically and biologically important in beef production. Therefore, this study was undertaken to investigate reproductive performance parameters including calving interval, parity for life time production. Data collected from 206,827 calvings were analyzed. There were no significant differences in calving interval and gestation days as parity increased from 2nd and 13rd parity cow, from spring to winter. However, we found a dramatic increase in calving interval after year 2000. About 1 month were increased per year ( y = 30.578x + 344.45 $R^2=0.9157$). Interestingly, we observed that parities for life time can be affected by birth weight. Calves with 23 kg at birth showed highest parities, $3.4{\pm}2.0$ times. In summary, this study provides valuable data on reproductive performance of Hanwoo and the data presented here can be used as a standard target for optimising and enhancing reproductive performance.

• Journal of Embryo Transfer
• /
• v.15 no.1
• /
• pp.1-8
• /
• 2000

The ultrasound-guided oocytes cllection (ovum pick-up ; OPU) has become a substitution for superovlation in cattle. The objective of this study was to examine the effect of OPU frequency on the in vitro production of embryos in Hanwoo cattle. Six cycling Hanwoo cows were distributed into two groups for either once or twice weekly OPU sessions. Oocytes were collected by ultrasound-guided follicle aspiration(SA600) using a 6.5HMz transducer and attached with 18 gauge needle, with vacuum pressure of 40 mmHg. The cumulus-oocyte complexes (COCs) collected from each donor were matured in TCM 199 supplemented with 10% fetal bovine serum at 5% CO2 in air at 38.5$^{\circ}C$ for 22h and in vitro matured oocytes were co-incubated with sperm(separated by Percoll gradient) for 6h. The zygotes were co-cultured on cumulus cell monolayer in 10ul droplets in the same culture medium and conditions used for IVM for 7 days. On Day 7 of culture, development to blastocysts was examined. Although the number of oocytes collected was variable depending on individuals, overall embryo production in the twice per week OPU sessions was better that in the once per week sessions(6~21 vs 2~7 blastocysts produced, respectively). Two cows(E, A) were good oocyte donors and embryo production was superior in cow C ; however, cow F was a poor donor as compared to the others. In conclusion, these results suggest that for embryo production, twice weekly OPU sessions were better than once per week for producing embryos in vitro from Hanwoo cattle.