• Journal of Animal Science and Technology
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• 제65권4호
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• pp.748-758
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• 2023

This study was conducted to investigate the change in activity and mounting behavior in Hanwoo (Korean Native Cattle) during the peri-estrus period and its application to estrus detection. A total of 20 Hanwoo cows were fitted with a neck-collar accelerometer device, which measured the location and acceleration of cow movements and recorded the number of instances of mounting behavior by the altitude data. The data were analyzed in three periods (24-, 6-, and 2-h periods). Blood samples were collected for 5 days after the prostaglandin F2α (PGF2α) injection, and the concentrations of estradiol, progesterone, follicle-stimulating hormone, and luteinizing hormone were determined by enzyme-linked immunosorbent assays. Activity and mounting behavior recorded over 2-h periods significantly increased as estrus approached and were more efficient at detecting estrus than over 24- and 6-h periods (p < 0.05). Endocrine patterns did not differ with the variation of individual cows during the peri-estrus period (p > 0.05). Activity was selected as the best predictor through stepwise discriminant analysis. However, activity alone is not enough to detect estrus. We suggest that a combination of activity and mounting behavior may improve estrus detection efficiency in Hanwoo. Further research is necessary to validate the findings on a larger sample size.

• Journal of Animal Science and Technology
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• 제65권4호
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• pp.818-837
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• 2023

Understanding adipocyte development in fetus during bovine pregnancy is important for strengthening fattening technology. Additionally, nutritional level of dams during pregnancy has the potential to improve offspring growth and fat development. The purpose of this study is to evaluate the intramuscular adipocyte development and expression level of related genes in bovine fetus, and the effect of increased crude protein (CP) intake during pregnancy on the growth performance and carcass characteristics of male offspring. Eighty six pregnant Hanwoo cows (average body weight, 551.5 ± 51.3 kg, age 5.29 ± 0.61 y) were used. Fetuses were collected at 90, 180 and 270 d of gestation from 18 pregnant Hanwoo cows. The remaining 68 pregnant cows were randomly assigned to 2 feeding groups. The control (CON) group was provided the standard protein diet (n = 34), and treatment (TRT) group was provided a diet with a 5% increase in CP intake (n = 34). Male offspring were divided into two groups according to protein treatment of the pregnant cows: CON male offspring (CON-O) and TRT male offspring (TRT-O). Intramuscular adipocytes were found in the fetal skeletal muscle after 180 days of gestation. Male calf's birth weight increased in the TRT group compared to that in the CON group (p < 0.002). The final body weight (p < 0.003) and average daily gain (p < 0.019) of male offspring were significantly higher in TRT-O than in CON-O. The feed conversion ratio was also improved by 10.5% in TRT-O compared to that in CON-O (p < 0.026). Carcass weight was significantly higher in the TRT-O group than that in the CON-O group (p < 0.003), and back fat was thicker in the TRT-O group (p = 0.07). The gross receipts and net income were higher in TRT-O than in CON-O (p < 0.04). Thus, fetal intramuscular fat can be formed from the mid-gestation period, and increased CP intake during pregnancy can increase net income by improving the growth and carcass weight of male offspring rather than intramuscular fat.

• Journal of Animal Science and Technology
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• 제55권6호
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• pp.501-508
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• 2013

This study was conducted to determine genetic correlations among carcass traits measured by ultrasound and real carcass measurements and to estimate indirect selection responses for real carcass traits based on ultrasound measurements in Hanwoo cows. To accomplish this, 22,080 ultrasound measurement records from 17,926 cows collected from 2001 to 2012 and 11,907 carcass records obtained from fattened cattle from 2008 to 2012 were used. Genetic parameters were estimated based on eye muscle area (EMA), backfat thickness (BF) and marbling score (MS) measured by ultrasound-scanning of live cows and using the official technique on chilled bovine half-carcasses after slaughtering. Heritability and genetic correlation for carcass traits were estimated using a mixed model equation that consisted of environmental effects as fixed parameters and additive genetic effects and residual effects as random parameters, assuming that traits were different between ultrasound and carcass measurements. This statistical method was applied to the average information restricted maximum likelihood method. The heritability of EMA, BF and MS measured by ultrasound were 0.33, 0.61 and 0.46, respectively, while the heritability estimates of the corresponding traits based on carcass measurements were 0.29, 0.40 and 0.38, respectively and the genetic correlation between ultrasound and carcass traits for EMA, BF and MS were 0.41, 0.78 and 0.67, respectively. The genetic correlation between ultrasound and carcass traits was highly positive. Additionally, the selection response for marbling score was estimated to be 0.42 per generation if the cows were selected based on the ultrasound scan marbling score with an assumed selection intensity of 0.8. Overall, these results indicate that the ultrasound scan technique would be applicable to judging cow selection for genetically improved meat quality.

• 농업과학연구
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• 제47권3호
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• pp.667-672
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• 2020

It is well known that intensive selection caused a decline in reproductive performance in dairy cattle. Interestingly, the reproductive performances including fertility and calving interval of Korean native beef cattle have declined in the last 20 years, suggesting that a breeding program focusing on carcass weight and intramuscular fat may affect the reproductive physiology in Korean native beef cattle, too. In this study, we analyzed the calving interval (CI) and selection index (SI) based on genome-wide association studies (GWAS) of Hanwoo cows for seven years (2013 - 2019). Multiparous cows (4.5 ± 0.11) were analyzed, which were bred by artificial insemination (AI). We first examined the distribution of the AIs and calving dates. About 40% of the AIs were carried out in May to June and October to December; subsequently, calving was observed from March to April and August to October, respectively, indicating the cows were seasonally bred. No correlation between CI and SI was found (y = 0.0459x - 17.64; R² = 0.0356), but the ratio of cows with a positive SI was higher in the longer CI group compared to the shorter group, suggesting that the selection for meat quality and quantity may affect the reproductive performances. In addition, the average value of SI was - 3.42 in the CI < 400 while + 5.79 in the CI > 400 although the values were not statistically significant. However, our results suggest that reproductive indices such as fertility and CI should be considered for sustainability in the Hanwoo breeding selection program.

• 생명과학회지
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• 제22권1호
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• pp.36-40
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• 2012

본 연구는 한우 암소의 산육 및 도체특성에 있어 오징어 부산물의 급여 효과를 알아보기 위해 수행되었다. 한우 16두(나이 7세, 체중$484.1{\pm}63.6$ kg)를 대조구 및 처리구(오징어 부산물 첨가), 등 2그룹(각각 8두)으로 완전임의 배치하였다. 사료급여는 두 그룹 모두 자유채식토록 하여 150일간 시험을 수행하였다. 일당증체량은 처리구가 대조구 보다 유의적으로 높았다(p<0.05). 시험기간 내 사료섭취량 및 사료요구율은 처리구가 대조구 보다 유의적으로 낮았다(p<0.05). 육량특성에 있어서, 등지방두께, 등심단면적 및 육량지수는 두 처리구간 비슷한 경향을 나타내었고, 도체중은 처리구가 363.4 kg 대조구 353.1 kg으로 처리구간 유의적 차이는 없었다. 육질특성에서는 육색, 지방색, 조직감 및 성숙도는 두 그룹간 유의적 차이가 없었다. 그러나 근내지방도 및 육질 1등급 이상 출현율은 대조구 보다 처리구가 높았다. 그러므로 본 연구의 결과 오징어부산물의 급여는 한우 암소의 산육 및 도체특성을 향상시키는 것으로 생각된다.

• 농업과학연구
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• 제43권3호
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• pp.369-378
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• 2016

Improving the reproductive traits of Hanwoo might decrease their production cost. Therefore, this study was conducted to investigate the effects of environmental factors [registration grade (basic, pedigree or advanced), birth year, birth season, parity, delivery year, and delivery season] on various reproductive traits (age at 1st service, age at 1st conception, age for 1st calving, days at 1st service postpartum, non-pregnant condition period, calving interval, gestation length, and number of services for conception) in Hanwoo (primiparous 12,219 heads, multiparous 10,471 heads). All data was acquired from Gyeongnam province areas which were surveyed from 2007 to 2015. All environmental factors significantly influenced (p < 0.01) reproductive traits of primiparous cows but, but not all environmental factors influenced multiparous cows. Primiparous cows registered as advanced grade showed significantly lower age at 1st service (by 15.36 days), age at 1st conception (by 8.66 days), and age for 1st calving (by 8.77 days) (p < 0.01) than those registered as basic grades. Age at 1st service, age at 1st conception and age for 1st calving were not significantly related to birth year in primiparous cows. As delivery years advanced from 2005 to 2012, all durations associated to reproductive traits tended to be shorter. Days at 1st service postpartum, non-pregnant condition period, and calving interval tended to be shortened as parity increased. Days at 1st service postpartum, days open, calving interval, and gestation in multiparous cows calved in winter were shorter than those in summer. The registration grade was not a effected with reproductive traits in Hanwoo.

• Journal of Animal Science and Technology
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• 제65권4호
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• pp.779-791
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• 2023

This study aimed to assess the effects of embryonic developmental stage, quality grade, and fresh or frozen/thawed conditions on the pregnancy rate and sex ratio of live offspring in Hanwoo (Bos taurus coreanae) cows. The quality and developmental stage of in vivo-derived (IVD) transferred embryos were evaluated using the standard criteria of the International Embryo Technology Society. The recipient cows were synchronized using conventional (estradiol benzoate and progesterone) protocols before embryo transfer. Embryos were transferred to 297 cows, and pregnancy was monitored for 60-70 days after embryo transfer. The pregnancy rates of fresh and frozen/thawed embryos were 56.90% and 52.49%, respectively. Pregnancy rates varied according to embryo quality (56.18% for grade 1 vs. 36.67% for grade 2). Pregnancy rates also varied by developmental stage and cryopreservation (67.86% vs. 63.49% for stage 4-1, 64.00% vs. 54.72% for 5-1, and 50.00% vs. 47.83% for 6-1, in fresh embryos vs. frozen/thawed embryos, respectively). For stage 7-1, the pregnancy rates were 72.73% for fresh embryos and 20.00% for frozen/thawed embryos. In 66 fresh embryos, the sex ratio of live offspring was 5:5, whereas it was 4(female):6(male) for frozen/thawed embryos among the 95 frozen/thawed embryos. The miscarriage rate was approximately 3% higher for frozen/thawed embryos than for fresh embryos (18.1% for fresh vs. 21.1% for frozen). Seasonal fertility rates were 33.3% in spring, 55.67% in summer, 52.8% in autumn, 60.0% in winter. The following male-to-female ratios were observed in different seasons: 6.7:3.3 in spring, 4.0:6.0 in summer, 5.5:4.5 in autumn, and 3.3:6.7 in winter. The current data revealed no significant differences in pregnancy rates between fresh and frozen/thawed IVD embryos. However, there was a lower pregnancy rate with advanced-stage frozen/thawed embryos (stage 7-1). The current study provides comprehensive results for the better optimization of embryo transfer in Hanwoo cattle to obtain the desired fertility rate, pregnancy rate, and sex ratio of calves. These results provide important insights into the factors that influence the viability and success of IVD embryo transfer in Hanwoo cows and may have practical applications for improving breeding programs and reducing production costs.

• 한국수정란이식학회지
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• 제25권3호
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• pp.141-144
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• 2010

In vivo embryo produced from Hanwoo donor cows were collected and transferred to Hanwoo recipients. Cows, at random stages of the estrous cycle, received Progesterone Releasing Intravaginal Device (CIDR-plus, InterAg, New Zealand) together with injection of 1 mg estradiol benzoate and 50 mg progesterone, and gonadotropin treatment began 4 day later. For superovulation, a total of 28 mg FSH was intramuscularly injected twice a day in the way of decreasing doses 4 day (5, 5, 4, 4, 3, 3, 2 and 2 mg). Twenty one Hanwoo donor cows were flushed on day 7 of estrus cycle with same FSH and artificial insemination by the same technicians. Embryos were recovered 7 days after the second insemination by flushing the uterus with Embryo Collection Medium. The results obtained were as follows: The rates of transferable embryos were 50.3%, and 78 fresh embryos at morulae and blastocysts stage were transferred into Hanwoo recipients on day 7 of estrus cycle. The pregnancy rates were first embryo transfer 55.6%, 2nd 62.9% and 3rd 57.9%, respectively. In conclusion, These results suggest that CIDR-based superovulation protocol may be effectively used for production of superior Hanwoo embryos. Also, since it seems the condition of recipient cows greatly affect pregnancy rate, it is very important to evaluate recipient for effective cattle production.

• 한국수정란이식학회지
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• 제26권1호
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• pp.27-32
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• 2011

본 연구는 OPU 유래 한우 수정란을 이식한 대리모의 품종이 임신 기간과 산자의 생시 체중에 미치는 영향을 분석하고자 6~7일차 OPU 유래 한우 체외수정란을 한우와 젖소 대리모에 이식하여 산자를 생산하였다. 1. 대리모에 따른 평균 임신 기간(젖소: $284.4{\pm}9.8$일, 한우: $280.9{\pm}6.2$일)과 산자의 생시 체중(젖소: $27.70{\pm}7.92\;kg$, 한우: $23.56{\pm}3.75\;kg$)에서 유의적인 차이가 없었다. 2. 임신 기간은 수송아지를 생산한 대리모(한우: $283.8{\pm}6.7$일, 젖소: $287.3{\pm}8.9$일)가 암송아지(한우: $277.3{\pm}3.3$일, 젖소: $280.1{\pm}9.9$일)를 임신한 대리모보다 유의적으로 길었다(p<0.05). 단태에서도 수송아지를 분만한 대리모의 임신 기간이 유의적인 차이가 있었다(p<0.05). 3. 산자의 성별에 따른 생시 체중은 암송아지(한우 대리모: $21.5{\pm}3.8\;kg$, 젖소 대리모: $21.5{\pm}6.1\;kg$)보다 수송아지(한우 대리모: $25.2{\pm}3.1\;kg$, 젖소 대리모: $32.3{\pm}6.0\;kg$)가 무거웠으며, 수송아지의 경우 품종간 유의적 차이를 보였다. 단태에서도 수송아지가 유의 하 게 높았다(p<0.05). 이상의 결과, OPU 유래 수정란을 이식한 대리모의 임신 기간은 대리모의 품종에 따른 차이는 없었으나, 분만된 산자의 성별에 따라 유의적인 차이기 있었다. 산자의 생시 제중은 수송아지가 유의적으로 높은 생시 체중을 보였고 임신 기간도 수송아지를 분만했을 때 유의적으로 길었다. 수송아지의 경우 품종간의 차이를 보였는데, 이러한 결과는 수정란이식에 의해 생산되는 송아지의 생시 체중과 대리모의 임신 기간은 태아의 품종보다 대리모의 품종이 영향을 미치는 것으로 판단된다. 본 연구에서 젖소 대리모가 한우 대리모보다 번식 적령기의 체중이 무거우므로 대리모의 품종이 산자의 생시 체중에 영향을 미치는 것으로 판단된다.

• 한국수정란이식학회지
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• 제30권3호
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• pp.189-193
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• 2015

Calculating break-even price of calf production is closely associated with reproductive efficiency. To determine the price, we need data from reproduction records including number of claves weaned, number of cows exposed for breeding, and annual cash coast per cow, and average weaning or market weight of claves sold and retained. Unfortunately, the data were not available in Korea native cow (Hanwoo). To evaluate the performance and the price, we collected calving interval from about 60,000 cows for last 10 years and estimated reproductive performance. Calving interval was increased 4.3% and pregnancy rate was decreased about 1.4~2.8% year-on-year. Increases in growth rates of number of cow and semen per calf supported the low reproductive performance. Finally, break-even price was calculated using estimated percent calf crop and demonstrated that growth rate of break-even price is larger than that of annual cash per cow, suggesting cow-calf profitability and financial efficiency in Korea native cow (Hanwoo) is getting worse.