Korean Native Black Goat: A Review on Its Characteristics and Meat Quality

Three predominant KNBG strains—Jangsu, Tongyeong, and Dangjin— are recognized as Korean purebred goats in the Domestic Animal Diversity Information System (DAD-IS) of the Food and Agriculture Organization of the United Nations (FAO; Lee et al., 2020b). The Jangsu strain is prevalent in Beo-nam-myeon, Jangsu-gun, Jeollabuk-do Province; the Tongyeong is concentrated in Yokjido, Tongyeong, Geongsangnam-do Province; and the Dangjin strain is commonly found in Anmyeondo, Taean, Chungcheongnam-do Province. Morphologically, Jangsu and Tongyeong strains typically characterized by black coat color, while the Dangjin strain often exhibits long black or dark brown coats (Fig. 1; Lee et al., 2019b). The strains also show differences in features such as wattles, horns, ears, tails, and beards, which aid in their identification. Recently, a new strain, the Gyeongsang-National-University (GNU) strain, was developed at Gyeongsang National University. This strain demonstrates exceptional genetic diversity, particularly in comparison to the Dangjin strain. Its development addresses the increasing demand for high-quality KNBG meat and aims to enhance the breed’s traits (Kim et al., 2020c).

Fig. 1. Three main strains of Korean native black goat. (A) Jangsu strains, (B) Tongyeong strains, and (C) Dangjin strains. Adapted from Kim and Lee (2020) with CC-BY-NC.

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KNBGs comprise approximately 80% of South Korea’s total goat population, highlighting their vital role in maintaining the country’s livestock biodiversity (Saturno et al., 2020). To preserve the unique genetic resources of KNBGs, various studies have employed microsatellite markers to evaluate genetic diversity across strains (Kang et al., 2021; Kang et al., 2023; Lee et al., 2020a; Park et al., 2019; Suh et al., 2012). Suh et al. (2012) used 30 microsatellite markers to analyze the genetic diversity of three major KNBG strains, identifying 277 distinct alleles, 102 of which were strain-specific. Expanding on this, Kang et al. (2021) provided a comprehensive evaluation of genetic diversity, including the GNU strain, through comparative analyses with crossbred goats in Korea. Using Neighbor-Joining tree analysis, the study revealed significantly greater genetic distances in crossbred goats compared to KNBG strains (Fig. 2). Additionally, the GNU strain exhibited closer genetic proximity to the Jangsu and Tongyeong strains than to the Dangjin strain. This difference is likely due to the geographical proximity of these regions, which facilitates gene flow and results in closer genetic clustering.

Fig. 2. Neighbor-Joining tree method among individuals, using Nei’s DA genetic distance index analysis results from 11 microsatellite loci. Adapted from Kang et al. (2021) with CC-BY-NC. TY, Tongyeong strain; JS, Jangsu strain; DJ, Dangjin strain; GNU, Gyeongsang-National-University strain; FG, crossbred line.

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Effective KNBG productivity is influenced by several critical factors, including housing, feeding, and reproduction management. Each of these factors plays a distinct role in optimizing growth, health, and reproductive success. Housing systems are particularly important in KNBG management, with two main approaches commonly utilized: extensive open sheds for shelter and intensive pens designed to optimize population density (Song et al., 2006). Given that many goat farms in Korea are situated in remote areas (Son et al., 2021), approximately 45% of KNBGs are raised on small-scale farms employing diverse housing methods (Son, 1999). For example, a farm in Cheongju, Chungcheongbuk-do, features a barn with a natural soil foundation, rice straw bedding, vinyl-enclosed walls, and an iron panel roof with transparent plastic plates (Byeon et al., 2020). In research settings, metabolic cages are frequently employed for dietary experiments (Cho et al., 2017).

Feeding practices play a vital role in influencing KNBG productivity, particularly through targeted dietary strategies. Recent studies highlight the benefits of high-protein diets incorporating a mix of roughage and concentrated feed. Typically, KNBGs are raised on pasture, with rice straw serving as the primary roughage, supplemented with commercial pellets after weaning (Lee et al., 2019a). During the growing period, they are provided with high-protein alfalfa grass, with alfalfa hay introduced during the finishing stage.

Productivity metrics, such as birth weight and weaning weight, serve as critical indicators of early growth and overall performance. For instance, birth weights for KNBG strains range from 1.9 to 2.3 kg for Dangjin, 2.0 to 2.1 kg for Jangsu, and 1.8 to 2.0 kg for Tongyeong (Table 1). Although KNBGs generally have lower birth weights compared to Boer and Saanen goats, their weaning weights (at 3 months of age) are comparable to Boer goats. This observation suggests their viability as meat-producing goats when appropriate feeding strategies are employed to improve growth and productivity.

However, KNBGs tend to exhibit slower growth rates compared to other breeds (Lee et al., 2019b). Research on growth performance has produced mixed findings. Some studies report no significant difference in daily weight gain (Choi et al., 2007) while others indicate improved performance with specific dietary treatment (Ahmed et al., 2015; Hwangbo et al., 2009). These results point to the need for optimizing diet formulations to enhance growth performance and strengthen the economic potential of KNBGs for meat production.

Reproductive management is another key factor in maximizing KNBG productivity. Female KNBGs reach puberty earlier than other breeds, typically experiencing their first estrus between 121 and 176 days, with cycles lasting 17–25 days (Song, 2003). This early maturity allows for first gestation to occur at 6–8 months, with an average gestation period of 150 days. The initial kidding usually occurs at 382.0±25.2 days in intensive systems and 412.1±32.7 days in extensive systems (Song et al., 2006). Challenges such as delayed reproductive cycles in twin-born females are addressed through strategies like estrus synchronization and semen collection with cryopreservation, which aim to enhance the KNBG population size and improve breeding efficiency (Kim et al., 2021a; Kim et al., 2021b; Kim et al., 2022b; Lee et al., 2018).

Future research should prioritize standardizing methodologies to reduce variability in studies of growth performance and reproductive efficiency in KNBGs. Furthermore, implementing genetic conservation practices for each strain is essential to protect and preserve genetic diversity. These practices should focus on strain-specific growth rates and the potential of crossbred animals, thereby optimizing overall performance of KNBGs.

Skeletal muscle contains three primary fiber types: Type I (slow-twitch oxidative), Type IIA (fast-twitch oxidative-glycolytic), and Type IIB (fast-twitch glycolytic). Type I fibers, darker in color due to high myoglobin content, support endurance and are found in muscles used for sustained activities, such as legs. Type IIA fibers balance endurance and strength with moderate oxidative and glycolytic capacity. Type IIB fibers, lighter in appearance and relying on anaerobic glycolysis, are found in muscles used for rapid and powerful contractions, such as the shoulders and back (Brooke and Kaiser, 1970). The distribution of these fibers affects muscle function and meat quality, influencing tenderness, juiciness, and flavor (Joo et al., 2013).

Extensive research has been conducted on muscle fiber composition in Korean livestock (Table 2), including Korean native beef cattle (Hanwoo beef; Hwang et al., 2010; Kim et al., 2000), pork (Cho et al., 2019; Eom et al., 2024; Hwang et al., 2018b), and KNBGs (Bakhsh et al., 2019; Hwang et al., 2017; Hwang et al., 2019). Observed muscles include the longissimus dorsi (LD), longissimus lumborum (LL), longissimus thoracis (LT), psoas major (PM), semimembranosus (SM), and gluteusmedius (GM). These studies have elucidated differences in muscle fiber types across species, with implications for meat quality attributes such as tenderness, flavor, and overall acceptability.

For KNBGs, the muscle fiber composition offers insights into meat quality across different ages (Table 2). Young goats tend to exhibit a balanced distribution of fiber types, particularly in muscles like the LD and GM, suggesting that their meat provides a desirable mix of tenderness and flavor suitable for a various culinary application. However, adult goats show a higher proportion of Type IIB fibers, particularly in the SM and GM muscles, which may result in tougher, leaner meat. These changes highlight the need for specific cooking methods, such as slow cooking, to enhance tenderness and improve overall eating quality of the meat (Hwang et al., 2019).

Studies on KNBG muscle fiber have shown variations across muscles and slaughter ages (Figs. 3A, B, C, and D). Research by Hwang et al. (2017) revealed significant differences in muscle fiber area among LL, PM, SM, and GM muscles (p<0.05). The PM muscle exhibited the highest area of Type I fibers, while LL and SM had lower percentages. LL had the largest percentage of Type IIA fibers, while SM had the highest percentage of Type IIB fibers, and PM h (p<0.05). Slaughter age also significantly impacted muscle fiber characteristics, with adult (18 mon) KNBGs showing larger muscle fibers compared to young (9 mon) goats.

Fig. 3. Serial sections of muscles from Korean native black goat, longissimus lumborum (LL; A), longissimus dorsi (LD; E, I), psoas major (PM; B, F, J), semimembranosus (SM; C, G, K), and gluteus medius (GM; D, H, L) stained for myosin ATPase reactivity after pre-incubation at pH 4.6 (A–D) and pH 4.5 (E–L). Magnification of 100× was used (bar=50 μm). (A–D) Adapted from Hwang et al. (2017) with CC-BY-NC; (E–L) Adapted from Hwang et al. (2019) with CC-BY-NC.

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The physicochemical properties of meat encompass both its physical and chemical characteristics, each playing a vital role in determining overall meat quality (Anneke et al., 2019). Key physical attributes include color, texture, and pH, while nutrient composition, fat content, and fatty acid profile represent important chemical characteristics. Among these factors, meat color is a critical quality indicator highly valued by consumers. In KNBG meat, color metrics such as CIE L*, CIE a*, and CIE b* are significantly influenced by the animal’s slaughter age (Table 3; Choi et al., 2023). Younger goats produce meat with a lighter, pinkish-red hue, attributed to lower myoglobin levels —the protein responsible for red color of muscle tissue (Saccà et al., 2019). As KNBG goats mature, increased myoglobin accumulation results in darker, more intensely red meat. Additional factors, including nutrition, cooling rate, muscle type, muscle pH, post-mortem storage conditions, oxygen exposure, and myoglobin concentration, also influence meat color (Jaramillo-López et al., 2021). Intramuscular fat content contributes to CIE b* in KNBG meat, with higher fat levels producing a more pronounced yellow hue (Choi et al., 2023).

Apart from age, meat color and overall quality are influenced by breed, diet, and processing methods. For instance, a low-energy diet can result in darker meat, likely due to reduced glycogen reserves, which subsequently lower pH and alter lactic acid production (Gardner et al., 2014). Consumer preferences often favor darker meat, which can be influenced by dietary and processing factors (Hughes et al., 2020). Variations in pH levels are also observed based on sex and rearing conditions, with males typically exhibiting lower pH values than females. Notably, Choi et al. (2023) reported significant reduction in pH levels in the LL muscle of female KNBG×Boer crossbreds slaughtered at a later stage. In contrast, by Bakhsh et al. (2018) found no significant differences in pH, color, or water-holding capacity between head-only electrical stunning and stunning-free methods.

The proximate analysis evaluates the primary components of meat, including moisture, crude protein, crude fat, ash, carbohydrate, and fiber. Research indicates no significant differences in crude protein and fat content between male and female KNBGs (Kim et al., 2020a). This consistency persists across various dietary enhancements, including browses, green tea by-products, alfalfa, or commercial concentrates (Ahmed et al., 2015; Choi et al., 2006; Hwang et al., 2018a; Kim et al., 2022a). KNBG meat is notably leaner than beef, pork, and chicken (Table 4) with protein content ranging from 17.23% to 21.27%, and relatively low fat levels (0.80% to 9.98%). Its high levels of UFAs, particularly oleic acid, enhance its umami taste and overall palatability of the meat (Table 5; Kim et al., 2022a).

KNBG meat is also rich in essential minerals such as potassium, sodium, phosphorus, calcium, and iron, which support skeletal structures, nerve transmission, and overall physiological functions. These minerals concentration vary across muscle types, slaughter ages, and cooking methods (Hwang et al., 2017; Hwang et al., 2018a; Kim et al., 2020a; Kim et al., 2020b; Kim et al., 2022a; Table 6). The meat’s high bioavailability of heme iron and low sodium content make it particularly beneficial for addressing deficiencies in vulnerable populations, such as infants, adolescents, pregnant women, and the elderly (Wood, 2017).

Research on KNBG initially focused on its extract, revealing significant mineral content and health benefits. Early studies, such as those by Kim et al. (1998), examined the mineral and fatty acid profiles of KNBG extract. Park and Kim (2000a) and Park and Kim (2000b) further confirmed its rich mineral composition, including calcium, potassium, phosphorus, magnesium, and sodium. Building on this foundation, subsequent innovations included Song and Jung (2002) KNBG granular tea infused with traditional herbs, and Song et al. (2004) KNBG pills enriched with danggui, licorice, perilla, and ginger. Yang et al. (2011) developed an herbal KNBG extract with potential obesity-suppressing properties, while Ha (2017) introduced a KNBG extract combining bones, vegetables, and mushrooms. Finally, studies by Lee (2017) and Lee (2019) led to the development of KNBG black soup with Epimedium koreanum, noted for its antioxidant and antidiabetic effects. KNBG meat, particularly in traditional Korean black goat soup (heukyeomso-tang), offers a low-fat, low-cholesterol, high-calcium, and high-iron alternative to beef and pork, renowned for its unique flavors and health benefits (Lee and Kim, 2008).

Consumer preferences for KNBG products reveal a variety of usage patterns and motivations. These preferences are primarily driven by the meat’s nutritional profile, low-fat content, and rich umami flavor. Consequently, it appeals to health-conscious consumers seeking alternatives to more common meats such as beef and pork. A comprehensive survey on KNBG meat consumption by Choi et al. (2022b) explored preparation preferences, reasons for selection, and influencing factors. Results showed that 38.2% of consumers prefer KNBG meat in soup, 28% grilled, and 19.9% in tonic extract, with other preferences also noted. Health benefits were cited by 27.9% of respondents as the primary reason for choosing KNBG meat, while 21.1% valued its suitability for families, and 15.8% appreciated its local availability. Positive feedback highlights the meat’s nutritional benefits, whereas its distinctive smell and tougher texture are often noted as drawbacks compared to other meats. Additionally, research on KNBG meat has increasingly focused on its application in various meat-based dishes, such as jerky (Baek and Kim, 2024) and sausage (Park et al., 2020). It has also explored its integration into traditional Korean recipes like bulgogi (Choi et al., 2022a) and tteokgalbi (Lee et al., 2023b).

KNBG meat is a notable source of bioactive compounds - naturally occurring substances that exert positive physiological effects on the body and contribute to various health benefits. Key bioactive components in KNBG meat include L-carnitine, creatine, creatinine, and anserine, each offering distinct advantages. L-carnitine, commonly found in meat and dairy, plays a crucial role in lipid metabolism and has been associated with weight management in obesity (Lee et al., 2016). Creatine supports energy metabolism and shows therapeutic potential in enhancing muscle strength and mass, particularly in elderly populations with age-related muscle wasting and neuromuscular disorders (Chrusch et al., 2001). Creatinine, a byproduct of muscle metabolism, serves as an indicator of renal function and is influenced by muscle mass and high-protein diets (Piéroni et al., 2017). Additionally, anserine and carnosine, found in skeletal muscle and nerve tissues, provide buffering and anti-inflammatory properties (Kaneko et al., 2017). Supplementation with these compounds may enhance cognitive functions and improve blood flow in certain brain regions among older adults.

The levels of these bioactive compounds in KNBG meat are influenced by factors such as sex, castration, dietary composition, and storage conditions (Table 7). Female and castrated goats generally exhibit higher concentrations of bioactive compounds compared to intact goats (Aung et al., 2023). Additionally, goats fed a low-alfalfa diet tend to have elevated levels of these compounds compared to those on a high-alfalfa diet (Kim et al., 2022a). Further studies are needed to elucidate the metabolic mechanisms under different dietary conditions and interventions.

The antioxidant potential of KNBG meat has been evaluated using assays, such as including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, ferric reducing ability of plasma (FRAP) activity, and oxygen radical absorbance capacity (ORAC). KNBG rib cuts show the highest ORAC activity compared to leg, neck, and loin cuts, exceeding the antioxidant capacity of Korean native black pig meat (Moon et al., 2021). The FRAP assay highlights that KNBG neck cuts possess significantly higher antioxidant activity than other cuts (Kim et al., 2022a). Kim et al. (2022a), noted that the antioxidant activity in KNBG meat may be enhanced by endogenous antioxidants present in concentrated diets, with differences observed between low- and high-pasture-fed goats.

Recent research has extended the focus of KNBG meat to its osteoprotective properties. Akter et al. (2024) investigated the effects of KNBG extract derived from leg and rib bones, highlighting its estrogen-like activity and potential benefits for bone health. The extract demonstrated anti-menopausal effects by promoting MCF-7 cell proliferation and upregulating estrogen-related genes (ERα, ERβ, and pS2). Furthermore, KNBG extract enhanced osteogenesis and mineralization in MC3T3-E1 cells by modulating the Wnt/β-catenin pathway, increasing levels of Runt-related transcription factor 2, osteoprotegerin, and collagen type 1. It also inhibited osteoclastogenesis by reducing the formation and activity of osteoclasts in RAW264.7 cells and downregulating key signaling molecules, including receptor activator of nuclear factor κB and tumor necrosis factor receptor-associated factor 6.

Although current research underscores the potential of KNBG meat bioactive compounds, in vivo studies remain limited and warrant further expansion. Future research should aim to bridge in vitro findings with practical applications in human health through well-designed in vivo models. Specifically, studies should evaluate the impacts of these compounds on lipid metabolism, muscle function, cognitive health, and bone density. Additionally, long-term investigations into the dietary incorporation of KNBG meat could provide critical insights into its potential as a functional food. Such research would not only substantiate its health-promoting claims but also enhance its value in both scientific and consumer domains.

Goat meat, particularly from intact buck goats such as KNBGs, is known for its distinctive aroma which can attract or deter consumers (Aung et al., 2023). This aroma and its associated flavor are largely influenced by VOCs, which are organic chemicals contributing to sensory qualities. Cooking methods further modulate the flavor profile, enhancing sweetness, saltiness, bitterness, or sourness—flavors often linked to high iron content (Flores, 2023). Advanced analytical techniques, such as electronic nose systems (Kang et al., 2013) and gas chromatography-mass spectroscopy (Kim et al., 2020a; Lee et al., 2023a) have provided detailed insights into the VOC composition of KNBG meat. Table 8 summarizes the VOCs identified under various treatments.

Studies highlight the impact of processing and physiological factors on KNBG VOC profiles. Kang et al. (2013) observed significant differences in VOC profiles between high-pressure processed (HPP) and untreated KNBG meat samples. Compounds such as 9,12-octadecadienoic acid, octadecanoic acid, and 2,6-nonadienal were notably prominent in HPP samples. The oxidation of n-3 long-chain fatty acids produces 2,6-nonadienal, which strongly influences goat meat’s flavor due to its low olfactory threshold (Paleari et al., 2008). Indole, a compound linked to boar taint odor, was also detected and is associated with elevated gonadal hormone levels in intact males, leading to consumer aversion due to its fecal-like smell (Flores, 2023; Zhao et al., 2017).

Sex and diet significantly influence VOC profiles within KNBG breeds. Kim et al. (2020a) demonstrated that intact males exhibited higher levels of VOCs, such as 1-hydroxy-2-propanone and 2,4-octadiene, compared to castrated males and females. These differences can be leveraged in marketing strategies to cater to diverse consumer preferences. Additionally, a high-forage diet reduces levels of 2,4-octadiene, contributing to milder flavor profiles in castrated and intact goats (Lee et al., 2023a). Compounds like 1-hydroxy-2-propanone, derived from glucose degradation, impart sweet, caramel-like odors, whereas 2,4-octadiene, linked to fatty acid oxidation, contributes to broader flavor complexity (Piveteau et al., 2000).

Comparative analyses have revealed significant variations in VOC profiles between intact males and female KNBGs. Female rib cuts exhibit higher concentrations of aromatic ethanol and 2-butanol, contributing sweet and oily aromas, respectively (Aung et al., 2023). In contrast, intact males demonstrate elevated levels of 1-octene, a compound associated with irradiation odors in goat meat, and 2,3-octanedione, known for its contribution to a pungent, cheesy aroma (Kim et al., 2020a). Branched-chain fatty acids, particularly those prominent in intact males, further contribute to the development of boar taint odor, influencing the characteristic flavor of KNBG meat (Paleari et al., 2008).

4-Methyloctanoic acid (4-MOA), a branched-chain fatty acid, is another key contributor to the distinct aroma of goat meat, often described as “gamey” or “sweaty” (Chen et al., 2012). Its concentration varies based on factors such as age, sex, and diet, with higher levels observed in older intact males due to increased lipid oxidation and hormonal influences (Tangkham, 2018). 4-MOA’s low olfactory detection threshold amplifies its sensory impact, often leading to consumer aversion, particularly in markets unaccustomed to goat meat flavors (Salvatore, 2003). Mitigation strategies focus on dietary manipulation, as forage-based diets have shown potential in reducing 4-MOA levels in goat fat (Tangkham, 2018). These dietary adjustments, combined with advanced cooking techniques offer effective strategies to balance goat meat’s natural flavor profile and improve consumer acceptance.