Comprehensive Analysis of Feed Barley
Comprehensive Analysis of Feed Barley: Genetic Types, Geographical Origins, and Quality Strategies in Livestock and Poultry Feed Formulation
A. Abstract
Feed barley (Hordeum vulgare) is considered a strategic and essential ingredient in the livestock and poultry feed supply chain, playing a significant role in dietary energy and fiber management. This article provides a comprehensive analysis of barley types based on genetic classification (two-row and six-row barley), geographical origin (major global producers), and their impact on nutritional quality. Findings indicate that barley quality should be evaluated beyond price, based on key technical parameters such as test weight (hectoliter weight) and beta-glucan content. Two-row barley, due to its higher kernel weight and better uniformity, is the preferred option in markets where energy density is critical, while the presence of beta-glucan limits its application in poultry diets unless appropriate enzymes are used. Continuous monitoring of mycotoxin contamination (particularly aflatoxin B1), considering logistical risks at Iranian ports, is an essential requirement in barley trade. Overall, adopting a purchasing strategy based on detailed technical analysis is necessary to ensure economic efficiency and maintain animal health.
B. Introduction: Strategic Importance of Feed Barley in the Feed Supply Chain
1. Historical Importance and the Role of Barley in Food Security
Barley (Hordeum vulgare) is one of the oldest cereal crops cultivated by humans, with a history dating back approximately 10,000 years [1], [2]. Researchers consider its probable origin to be the Zagros Mountains in western Iran, southern Anatolia, and Palestine [2]. Throughout history, barley has been used not only as a human food source but also as an energy-rich feed ingredient for livestock and as a raw material for fermented products [2]. Historical evidence suggests that even Roman gladiators consumed barley due to its high energy supply [2]. Today, this cereal is recognized as a strategic feed ingredient that, with a moderate crude protein content of approximately 11–12%, is considered an ideal feed component for both ruminants and non-ruminants [3, 4].
Due to climatic limitations in domestic production of feed ingredients, Iran has a strong dependence on imports to meet the requirements of animal protein production [5, 6]. Barley, along with corn and soybean meal, is among the country’s major and widely consumed imported feed ingredients [6]. Sustainable production of meat, milk, and eggs in Iran is directly dependent on the continuous supply of high-quality feed ingredients [5]. Significant fluctuations in global production markets [7, 8] and changes in trade routes (such as the impact of the Ukraine war on grain markets [8]) can directly affect protein supply security and production costs within the country. Therefore, accurate knowledge of imported barley types, technical characteristics, and quality evaluation methods is essential for managing supply chain risks in domestic markets.
Section 1: Scientific Fundamentals and Morphological Classification of Feed Barley
The classification of feed barley based on spike structure directly influences its nutritional composition and application in feed formulation. The two primary classification systems include genetic differences (two-row and six-row barley) and grain structure differences (hulled and hulless barley).
1.1. Two-Row vs. Six-Row Barley: Differences in Uniformity, Kernel Weight, and Adaptability
Based on spike structure, barley is divided into two main groups: two-row barley and six-row barley [9, 10]. These two groups possess different genetic structures that influence developmental processes and quantitative traits [9, 10].
In six-row barley, all three spikelets located at each node of the spike axis are fertile, whereas in two-row barley, only the central spikelet is fertile [9, 10, 11]. This morphological difference results in key variations in grain quality:
Kernel Weight and Uniformity: Two-row barley generally has significantly higher 100-kernel weight and better uniformity compared with six-row barley [9, 11]. This characteristic is attributed to the smaller size of lateral florets in six-row barley [11]. Higher uniformity is particularly important for industrial feed processing operations (such as grinding and pelleting), where consistency in particle size distribution is required.
Yield Potential and Adaptability: Six-row barley generally demonstrates higher yield potential, particularly under high-input conditions (such as adequate access to fertilizers and water) [10]. In contrast, two-row barley shows greater adaptability to environmental stresses and variable growing conditions [10].
Nutritional Composition: In terms of protein content, six-row varieties generally contain higher protein levels and are often preferred for animal feed, whereas two-row varieties typically have lower protein content and are primarily used for malt production [1].
From a feed formulation management perspective, these differences directly affect feed cost and final efficiency. Two-row barley, due to its better uniformity and higher kernel weight, provides greater nutrient density. This characteristic is particularly important in poultry diets or high-producing dairy cattle diets, where concentrated energy supply is required. The lower uniformity of six-row barley may create challenges in industrial processing and increase the cost per unit of dietary energy. Additionally, regarding anti-nutritional factors, two-row varieties often contain higher levels of beta-glucan [12], which requires special consideration in poultry diet formulation.
1.2. Hulled vs. Hull-less Barley: The Impact of Hull Presence on Energy Value and Digestibility
Another important classification of barley is based on the presence or absence of the hull (outer covering) of the grain. Conventional barley contains a tough hull that accounts for approximately 10–14% of the grain weight [13]. This hull contains high levels of fiber (crude fiber) and has low digestibility.
In contrast, hull-less barley lacks this outer covering, and its kernels are released from the hull during maturity, similar to wheat grains, allowing for easier separation [13].
Differences in this structure result in significant nutritional implications:
Nutritional Value and Energy: Due to the removal of the outer hull, hull-less barley contains lower crude fiber levels and higher amounts of starch, protein, and the amino acid lysine [13]. This directly increases its metabolizable energy (ME) value.
Application in Poultry Nutrition: Hull-less barley has higher digestibility and energy availability in poultry diets and can provide up to 82% of the energy supplied by imported corn [13]. This represents a major advantage compared with conventional barley, which has greater limitations in poultry nutrition.
This difference creates a strategic decision for importers. While conventional barley, due to its higher physical fiber content, is beneficial for ruminants (such as cattle), hull-less barley is a superior option for providing energy in monogastric animal diets (such as poultry) and reduces challenges associated with anti-nutritional factors. Therefore, if an importing company aims to target the poultry market, importing hull-less barley (despite its higher cost) can provide a significant competitive advantage compared with conventional barley.
Section 2: Feed Chemistry and Nutritional Value of Barley
2.1. Macronutrient Composition: Comparison of Barley Protein, Starch, and NDF with Reference Cereals (Corn and Wheat)
The chemical composition of feed barley demonstrates that this cereal is an important source of energy and fiber. On average, barley contains approximately 86% dry matter, 12.3% crude protein, 57% starch, and 2.5% fat [4]. However, comparing these values with other cereals helps determine its role in feed formulation.
Compared with wheat, barley contains higher fiber and lower starch levels [3]. This difference results in lower digestibility of barley in monogastric animals (such as poultry) compared with wheat [3].
In ruminants, barley is rapidly fermented in the rumen due to its high starch content, producing considerable energy that contributes to increased milk protein production and accelerated growth [3]. This energy is mainly derived from starch. However, analyses show that quality variations in barley can be significant, with crude protein levels ranging from 6% to 14% [3]. Such variation in protein and starch content directly affects the quality of the final concentrate feed, demonstrating that relying solely on the name “barley” is insufficient for precise feed formulation. Suppliers should provide detailed batch analyses (including protein, fiber, and starch percentages) to allow farmers to accurately calculate the cost of dietary energy and protein.
2.2. Micronutrient Profile and Nutritional Limitations
In addition to providing energy and protein, barley contains various micronutrients, although certain limitations should be considered.
From a protein perspective, barley, like other cereals, has moderate protein quality and is particularly deficient in the essential amino acid lysine [2, 3]. Lysine is an essential amino acid that is highly important for growth and performance, especially in poultry and swine.
Regarding vitamins and minerals, barley is generally poor in fat-soluble vitamins (A, D, and E) and the mineral calcium [2, 3]. Notably, processing wet barley grains with propionic acid can further reduce the vitamin E content of barley [3].
These nutritional limitations highlight the necessity of specialized supplementation in barley-based diets, particularly when barley is included at high levels. Deficiencies in calcium and vitamins [3] mean that feed manufacturers must incorporate vitamin premixes and mineral supplements (such as dicalcium phosphate) when using barley to ensure nutritional balance. This creates a potential market opportunity for the import and supply of complementary feed products alongside primary feed ingredients by major companies such as Zarrin Gheleh.
Section 3: Geographical Origin and Global Trade Standards
The sustainability of barley supply in the Iranian domestic market is highly dependent on understanding global sources and strictly applying physical quality standards in international trade.
3.1. Key Global Producers and Exporters
Global barley production is highly concentrated. According to 2024/2025 data, the European Union accounts for 35%, Russia for 11%, and Australia for 9% of global barley production, making them the largest players in the barley market [14]. Other important global supply sources include Canada, Ukraine, and Argentina [14].
Barley trade, like other grains, is strongly influenced by geopolitical risks. Dependence on major sources such as Russia and Ukraine exposes importers to significant global market fluctuations and supply chain disruptions [8], [15]. Under these conditions, supply diversification becomes a strategic priority for Iranian importers. The objective is to reduce dependence on a single region and explore alternative sources (such as Canada or Kazakhstan) to maintain supply stability under changing conditions.
3.2. Key Physical Indicator: Test Weight (Hectoliter Weight)
Test weight (hectoliter weight) is one of the most important and widely used physical indicators in global barley trade. This parameter, which measures the weight of 100 liters of barley [16], is used as a rapid indicator for estimating grain density and barley starch/energy content due to its ease of measurement [17].
International and domestic standards classify barley based on this indicator as follows:
Table 1: Key Physical Indicators of Feed Barley (Test Weight)
| Quality Parameter | Reference Standard | High Grade [kg/hl] | Minimum Commercial Standard (Good Feed) [kg/hl] |
|---|---|---|---|
| Test Weight (Hectoliter Weight) | ISIRI 3106 | > 65 [17] | 60–65 [17] |
A test weight below 60 kg/hl indicates poor quality [17]. Barley with a lower test weight generally has lower starch content and, consequently, a higher proportion of fiber/hull [17]. This reduction in energy density directly decreases the economic value of the feed ingredient, as nutritionists must add larger amounts of energy supplements (such as corn or fat powder) to achieve the desired dietary energy level. Therefore, importers should establish minimum test weight benchmarks in purchase contracts to prevent the importation of “light barley” with low economic efficiency.
Section 4: Quality Challenges and Anti-Nutritional Factors (Risk Management)
Quality management in barley imports is not limited to controlling physical indicators; precise control of anti-nutritional factors and contaminants is also critically important.
4.1. Beta-Glucans: Anti-Nutritional Effects and Enzymatic Solutions
One of the major technical challenges in barley utilization, particularly in monogastric animal diets, is the presence of beta-glucans. Beta-glucans are polysaccharides found in the cell walls of barley [18].
These compounds have anti-nutritional effects:
Intestinal Viscosity: Beta-glucans increase the viscosity (stickiness) of the gastrointestinal contents [3, 12].
Reduced Performance: This increased viscosity reduces nutrient absorption and negatively affects growth performance and weight gain, especially in broiler chickens [3, 19].
The beta-glucan content of barley can vary due to genetic and environmental factors. Two-row barley varieties generally contain higher levels of beta-glucans compared with six-row varieties [12]. Additionally, cultivation under hot and dry conditions during the grain-filling stage can increase beta-glucan levels [12].
To overcome this challenge, the use of beta-glucanase enzyme (Glucanase) is essential [3, 19]. Research has shown that using an appropriate enzyme dosage (such as 0.05% of the diet) can allow barley to completely replace corn in broiler diets without significant differences in growth performance compared with the control group [19]. This demonstrates that successful marketing of barley to the poultry industry requires not only supplying the ingredient but also providing technical recommendations or complementary enzyme solutions; otherwise, it may create significant technical risks for customers.
4.2. Mycotoxin Risk Management (Aflatoxin and DON)
Mycotoxin contamination is one of the most serious threats to livestock and poultry health, transmitted through feed ingredients [20, 21]. Barley, similar to corn and wheat, is susceptible to contamination by toxins such as DON (vomitoxin) and aflatoxin B1 [22, 21].
The contamination risk in Iran increases due to logistical challenges, as imported feed ingredients stored at major ports, which are often located in hot and humid regions, are exposed to greater fungal contamination risks during transportation, storage, and distribution [20, 21].
National and international standards define strict permissible limits to protect animal health. According to Iranian national standards (such as ISIRI 5925/6401), the maximum allowable concentration of aflatoxin B1 in livestock and poultry feed is 20 ppb (nanograms per gram) [20, 21, 23].
Table 2: Maximum Allowable Mycotoxin Limits in Livestock and Poultry Feed (Based on Iranian National Standards)
| Mycotoxin Type | Reference Standard | Maximum Allowable Level in Animal Feed (ppb) | Impact on Animal Health |
|---|---|---|---|
| Aflatoxin B1 | ISIRI 5925/6401 [16, 23] | 20 [20, 21] | Causes disease, reduces production, and threatens human health [20, 21] |
| Ochratoxin | ISIRI 5925/6401 [23] | 50 [20, 21] | — |
| DON (Vomitoxin) | ISIRI 5925/6401 [23] | 1000 [20, 21] | — |
Importers must ensure compliance with these permissible limits through continuous specialized testing (such as High-Performance Liquid Chromatography (HPLC) in accordance with Standard 6401 [23]) at multiple stages, including the origin country, port of entry, and storage facilities. This strict quality control process strengthens the company’s competitive advantage in Iran’s animal feed ingredient market.
Section 5: Application of Barley in Specialized Feed Formulation
Due to its unique composition (energy, protein, and fiber), barley has diverse applications in animal nutrition and feed formulation. However, species-specific limitations must also be considered.
5.1. Application in Ruminants (Dairy and Beef Cattle)
Barley is considered a desirable and high-energy feed ingredient for ruminants [3]. The starch in barley is extensively fermented in the rumen, providing the energy required for milk production and accelerated growth [3]. Furthermore, barley silage can contribute to increasing milk fat percentage [24].
Main limitation: Excessive barley intake may lead to ruminal acidosis (reduction in rumen pH) and bloat [3, 25].
Optimal inclusion level: The maximum recommended level of barley in diets for dairy cattle, finishing calves, and ewes is approximately 50% of the concentrate portion, while for finishing lambs it is 25%, and for growing and finishing diets it is around 30% [6].
Technical recommendation: To improve digestibility and reduce the risk of acidosis, barley should be properly processed (such as coarse grinding or flaking), and its inclusion level should be increased gradually in the diet [3].
5.2. Application in Monogastric Animals (Poultry and Swine)
The main challenge associated with the use of barley in poultry and swine diets is the presence of beta-glucans, which can negatively affect nutrient absorption and growth performance [3, 19].
Enzymatic solution: To overcome this limitation, the use of the enzyme beta-glucanase is essential [3, 19]. Research has shown that with an appropriate enzyme dosage (such as 0.05% of the diet), barley can completely replace corn in broiler diets without causing significant differences in growth performance compared with control groups [19].
Comparison with corn: Although corn remains the primary choice for poultry due to its higher metabolizable energy content [13], hull-less barley can be considered a competitive and economical alternative due to its favorable energy and protein value.
Table 3: Barley Inclusion Limitations in Key Animal Diets
| Animal Species | Maximum Recommended Level in Complete Diet (%) | Main Limitation | Technical Solution |
|---|---|---|---|
| High-producing dairy cattle | Up to 50% of concentrate [6] | Risk of ruminal acidosis and bloat [3] | Coarse grinding or flaking |
| Finishing lambs and sheep | 25–30% [6] | Acidosis and excessive softening of carcass fat [3] | Use of buffers and gradual adaptation to the diet |
| Broilers | Limited (usually <20%) [3] | Intestinal viscosity caused by beta-glucans [19] | Mandatory use of beta-glucanase enzyme [19] |
C. Conclusion
Feed barley, as a critical component of the animal feed supply chain, requires a multidimensional evaluation that goes beyond market price. Accurate analysis of technical characteristics and geographical origin is the key to risk management and optimized feed formulation.
Strategic Purchasing Criteria for Feed Barley
Genetic prioritization:
When targeting high-performance markets (poultry and high-producing dairy cattle), preference should be given to importing two-row barley (due to its higher grain uniformity and kernel weight) or hull-less barley (due to its higher metabolizable energy value) [11, 13].Control of physical quality indicators:
Verification of a test weight above 65 kg/hl, as an indicator of desirable energy density, should be incorporated as a minimum commercial standard in purchasing contracts [17].Health risk management:
Implementation of strict quality control procedures to ensure compliance with the maximum permitted level of Aflatoxin B1 (20 ppb) at both origin and destination points is essential for protecting animal health and maintaining company reputation [21, 23].Sustainable supply and source diversification:
Considering dependence on major global suppliers and geopolitical risks, adopting a diversified sourcing strategy (beyond the European Union and Russia) and managing alternative logistics routes are critical for maintaining supply stability in the Iranian market [14, 8].
D. References
Agronomic barley: Comparison of the structure and nutritional composition of two-row and six-row barley.
https://ijfcs.ut.ac.ir/article_84347.htmlHistory, origin, and medicinal properties of barley.
https://rasekhoon.net/article/show/126648Nutritional advantages, limitations (beta-glucan and lysine), and challenges of high barley inclusion in ruminant diets.
http://feedonline.ir/Chemical analysis of feed barley (protein, starch, and dry matter).
https://gandomineh.com/Food security, animal protein production, and dependence on imported feed ingredients in Iran.
https://biofinance.ir/Global barley production distribution statistics (2024/2025) and key producing countries.
https://www.fas.usda.gov/Impact of geopolitical changes on global grain markets and supply chain disruptions.
https://davannews.ir/Comparison of grain weight, uniformity, and yield components in two-row and six-row barley.
https://journals.ut.ac.ir/article_84347.htmlChanges in barley beta-glucan content under genetic and environmental influences.
http://rap.sanru.ac.ir/Differences between hull-less and conventional barley and their metabolizable energy value in poultry nutrition.
https://vj.areeo.ac.ir/Methods for determining grain bulk density and aflatoxin measurement according to Standard 6401.
https://old.iranslal.com/Barley purchasing checklist.
https://tdanehk.ir/buy-barley-checklist/Chemical structure of beta-glucans and their presence in cereals such as barley.
https://fartakadd.com/betaglucan/Effect of beta-glucanase enzyme on broiler performance in diets containing high levels of barley.
https://civilica.com/Fungal toxins and their impact on feed safety and quality.
http://smsm.ir/Mycotoxin contamination of feed ingredients (barley) and its impact on animal feed safety.
https://vj.areeo.ac.ir/Maximum barley inclusion levels in animal nutrition (dairy cattle and fattening animals) and related limitations.
https://pasadtrade.com/Effects of replacing corn silage with barley silage on dairy cow performance (increase in milk fat percentage).
https://ijas.ut.ac.ir/Risk of feed contamination at import ports and in warm and humid regions.
https://bbk-iran.com/
