Publications by authors named "Hong Gu Lee"

It is widely known that heat stress (HS) has negative effects on dairy cows, such as a reduction in milk production and milk protein. However, there has been no research yet on the effects of HS at the bovine mammary epithelial cells (MAC-T) level and the function of L-leucine (LEU) and sodium acetate (ACE) in reducing HS. In this study, we evaluated the negative effects of HS at various temperatures on MAC-T and verified whether LEU and ACE are effective at reducing HS and increasing protein synthesis.

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  • The study examined how different incubation temperatures affect ruminal fermentation and microorganisms in an in vitro setup, using rumen inoculum from Holstein heifers.
  • Results indicated that higher incubation temperatures increased NH-N concentrations and total volatile fatty acids (TVFAs), while decreasing liquid-associated bacterial amounts, with notable interactions between protein and energy levels.
  • The findings highlighted the complexities of ruminal metabolism under varying conditions, suggesting that while dietary adjustments can influence fermentation and microbial activity, in vitro experiments might not fully capture the physiological responses of the entire organism.
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Objective: This study evaluated the effects of increased levels of dietary total digestible nutrient (TDN) and crude protein (CP) using protected fat (PF), soybean meal (SB), and heat-treated soybean meal (HSB) on performance, physiological parameters, and behavioral measurements of early-fattening Hanwoo steers under heat stress conditions.

Methods: Thirty-six steers (480.9±58.

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  • The study researched how different temperatures affect muscle differentiation in bovine muscle cells, particularly looking at the effects of heat stress levels (mild vs. severe) and the protective role of vitamin E as an antioxidant.
  • Results indicated that mild heat stress (39°C) promoted early muscle differentiation, while severe heat stress (41°C) had detrimental effects on muscle-specific gene expression by day 6.
  • Vitamin E treatment showed potential in mitigating some negative impacts of severe heat stress on gene expression and protein content, highlighting its role in muscle cell health under stress conditions.
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Rice is a staple crop in Asia, with more than 400 million tons consumed annually worldwide. The protein content of rice is a major determinant of its unique structural, physical, and nutritional properties. Chemical analysis, a traditional method for measuring rice's protein content, demands considerable manpower, time, and costs, including preprocessing such as removing the rice husk.

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  • The study focused on the effects of 7 days of heat stress on early lactating Holstein cows in controlled settings, comparing low-temperature, low-humidity (LTLH) and high-temperature, high-humidity (HTHH) conditions.
  • The HTHH group experienced significant negative impacts, including a 12% drop in dry matter intake, a 23% increase in water intake, and reductions in milk yield and protein production by 10% and 20%, respectively.
  • Additionally, physiological changes were noted in the HTHH group, such as altered blood parameters (reduced white blood cells and increased glucose), heightened stress indicators (elevated cortisol), and increased body temperatures, demonstrating their greater vulnerability to heat stress compared
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Objective: This study aimed to determine the effects of increasing energy and protein levels in diets by including protected fat (PF), glycerol (GL), and soybean meal (SBM) on growth performance, physiological parameters, carcass characteristics, and behavioral measurements of late-fattening Hanwoo steers under heat stress conditions.

Methods: Thirty-six steers (initial body weight, 724.9±58.

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Climate change increases global temperatures, which is lethal to both livestock and humans. Heat stress is known as one of the various livestock stresses, and dairy cows react sensitively to high-temperature stress. We aimed to better understand the effects of heat stress on the health of dairy cows and observing biological changes.

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The objective of this study was to determine whether adding phytoncide oil (PO) and soybean oil (SBO) to the dairy cow diet could increase milk conjugated linoleic acid (CLA) and depress methane (CH) emissions in Holstein dairy cows. Rumen fermentation was conducted at four levels of SBO (0, 1, 2, and 4%, on DM basis) and two levels of PO (0 and 0.1%, on DM basis) with in vitro experiment.

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  • - The review focuses on the impact of methane emissions from livestock, especially cattle, on climate change, noting that methane accounts for 14-16% of global emissions.
  • - It assesses both traditional and AI-based methods for measuring methane emissions, stressing the need for region-specific approaches and accurate data collection.
  • - The study underscores the importance of integrating effective measurement techniques for methane in livestock management to enhance climate change mitigation efforts.
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  • The study assessed the impact of a complex natural feed additive on rumen fermentation, growth performance, and carcass quality in Korean-native steers over two separate experiments.
  • Results showed that adding the feed additive increased total gas production and volatile fatty acids, especially butyrate, indicating enhanced rumen fermentation.
  • However, the treatment group exhibited lower average daily gain and reduced backfat thickness, suggesting that while the additive affects fermentation positively, it may negatively influence growth.
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In this study, we examined the effects of rumen-protected L-tryptophan supplementation on the productivity and physiological metabolic indicators in lactating Holstein cows under heat stress conditions. The study involved eight early lactating Holstein cows (days in milk = 40 ± 9 days; milk yield 30 ± 1.5 kg/day; parity 1.

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Objective: This study was conducted to assess effects of heat stress on growth performance, physiological parameters, and blood profiles of Hanwoo steers during early-fattening period in climate chambers.

Methods: Four Hanwoo steers (body weight, 454.3±10.

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  • The study examined how varying dietary energy levels impacted the growth and stress response of Korean native calves under heat stress.
  • Calves were divided into three energy groups (low, medium, high) and exposed to different heat stress levels, revealing that severe heat stress negatively affected growth metrics and increased certain blood metabolites.
  • Findings suggest that higher energy intake may enhance calves' ability to cope with heat stress by reducing muscle degradation and promoting glucose production.
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  • The study evaluated rumen temperature and behavior in estral and non-estral Korean Native cattle using bolus sensors.
  • Estrus cattle showed significantly higher mounting behavior, vaginal temperature, and lower mucus resistance compared to non-estral cattle.
  • Findings suggest that monitoring rumen activity and temperature can be an effective method for detecting estrus in cattle.
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The process of myogenesis, which involves the growth and differentiation of muscle cells, is a crucial determinant of meat yield and quality in beef cattle. Essential nutrients, such as vitamins D and A, play vital roles in the development and maintenance of various tissues, including muscle. However, limited knowledge exists regarding the specific effects of vitamins A and D in bovine muscle.

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This study was conducted to investigate the effect of heat stress (HS) on physiological, blood, and behavioral parameters, according to the temperature-humidity index (THI), in beef steers. Twelve Korean native beef steers (342.7 ± 13.

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The purpose of this study was to investigate the effect of cold stress (CS) on the physiological, blood, and behavioral parameters of beef cattle according to their growth stage. Twelve calves in the growing stages (220.4 ± 12.

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This study investigated the effects of L-glutamine (Gln) supplementation on growth performance, physiological traits, heat shock proteins (s), and gene expression related to muscle and adipose tissue development in Hanwoo steers under heat stress (HS) conditions. Eight Hanwoo steers (initial body weight [BW] 570.7 ± 43.

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Excessive endogenous or exogenous levels of the stress hormone cortisol have negative effects on various tissues, including the skin. (IP), used in traditional medicine and perfumes, exhibits biological activities, such as antioxidant and anti-inflammatory activities. In this study, we aimed to investigate the inhibitory effect of IP extract (IPE) on cortisol activity in human skin cells.

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  • Understanding the classification of stress types is essential for recognizing the difference between beneficial (eustress) and harmful (distress) stress in animals.
  • Non-intrusive methods for assessing animal stress levels and identifying the most appropriate type of stress for their environment are crucial for accurate measurements.
  • The review emphasizes various body matrices, like hair, saliva, and urine, for evaluating stress hormones, highlighting hair's reliability for assessing long-term stress despite some skepticism in existing literature.
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The interest in cultured meat is increasing because of the problems with conventional livestock industry. Recently, many studies related to cultured meat have been conducted, but producing large-sized cultured meat remains a challenge. It is aimed to introduce 3D bioprinting for producing large cell aggregates for cultured meat production.

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This survey investigated, using robotic milking and rumen sensors, the effects of an adjusted temperature−humidity index (THI) in different geographical areas on milk yield, fat and protein, rumen temperature, and activity in lactating Holstein cows. We additionally explored the effect of parity on milk and rumen temperature and activity under different THI levels during the summer. From January to September 2020, four farms (276 dairy cows) were subjected to the use of robot milking machines, and two farms (162 dairy cows) to the use of rumen sensors.

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In three consecutive studies, we evaluated the effects of noni (Morinda citrifolia) meal on rumen fermentation and degradation characteristics, production performance, physiological parameters, and milk fatty acid profile in Holstein dairy cows. In in vitro (first study) and in situ (second study) experiments, rumen fluids from two fistulated Holstein dairy cows were used. The concentration of noni meal added was 0 (control), 1, 3, 5, or 7% of the basal diet (DM basis).

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