Hazem Khaled Ataya
Executive Manager
Al-Khawas Feed Mill

Efficiency in modern feed manufacturing relies not on optimizing standalone machines, but on controlling the entire process chain as a unified system from raw material intake and conditioning to pelleting and SCADA-driven data management. Minimizing process variation, ensuring equipment reliability, and maintaining consistent quality are only possible when data is transformed into an active tool for continuous operational improvement.

Feed manufacturing is no longer simply the process of mixing raw materials to meet a nutritional formula. It is an integrated industrial system in which raw-material characteristics, particle size, weighing accuracy, mixing uniformity, steam conditioning, pelleting, cooling, screening, packaging, equipment reliability, quality control, and production data continuously interact. A change in one process can affect several others; therefore, efficient feed production requires control of the entire process rather than optimization of individual machines.

FROM RAW MATERIALS TO A FINISHED FEED 

The process begins with receiving, conveying, storage, cleaning, weighing, grinding, and batching. Conveyors, bucket elevators, silos, bins, feeders, and weighing systems must operate as a coordinated material-flow system. Dosing systems commonly use separate weighing arrangements for macro- and micro-ingredients, and advanced systems can weigh several ingredients simultaneously. Batch size depends on scale capacity, mixer volume, bulk density, and required production rate; weighing capacities may range from approximately 0.5 to 5 tonnes or more depending on plant design.

Grinding is critical because particle size affects mixing, conditioning, pelleting, energy consumption, and final feed quality. Hammermills and roller mills are selected according to raw-material characteristics and the required particle-size distribution. In post-grinding systems, grinding time can become a major limitation of batch-cycle time; maintaining hammers, screens, aspiration, and feed rate is therefore essential for maintaining throughput.

MIXING UNIFORMITY AND LIQUID ADDITION

Mixing aims to distribute all ingredients uniformly throughout the batch. Paddle, ribbon, and vertical mixers are commonly used, with single- or twin-shaft paddle configurations depending on design. An indicative mixer fill level is approximately 75%, with about 30 seconds of dry mixing, followed by approximately 20–30 seconds after liquid addition. A complete mixing cycle may be around 3 minutes, excluding discharge, although actual settings must be validated for each mixer and formulation.

Mixing performance is commonly evaluated using the Coefficient of Variation (CV). Approximately ten samples from different locations within the mixer can be used for a uniformity test. As an operational guide, CV values of ≤5% indicate highly uniform mixing, >5–10% represent acceptable-to-good uniformity, >10–15% require investigation and improvement, while >15% indicate a significant uniformity problem. The standard statistical definition is CV = Standard Deviation ÷ Mean × 100.

A high CV may originate from incorrect dosing, differences in particle size or density, inadequate mixing time, poor micro-ingredient distribution, liquid spray problems, residual material inside the mixer, or leakage through discharge gates. Importantly, poor mixing must be distinguished from segregation after mixing, which can occur during conveying, transfer, storage, or loading even when the initial mixer CV is satisfactory.

STEAM CONDITIONING AND THERMAL PROCESSING

Steam conditioning connects mixing with pelleting and strongly influences pellet quality and production capacity. The main variables are steam quality, pressure, temperature, moisture addition, retention time, and feed response.

Indicative conditioning parameters include a retention time of 45–60 seconds and a conditioning temperature of approximately 72–90°C, depending on formulation and equipment. Starch gelatinization begins at approximately 72°C. A representative calculation in the process data gives a post-conditioning feed temperature of approximately 76°C, with moisture gain of roughly 0.7 percentage points for each 10°C temperature increase under the stated conditions.

Steam pressure after the pressure-reducing valve is typically around 1–1.5 bar, while steam temperature at the conditioner may be approximately 105–110°C. The distance between the pressure-reducing valve and conditioner may be approximately 3–20 m, depending on plant design. The boiler operating range described is approximately 6–15 bar, with about 60–70% water filling in the example system, leaving the remaining volume for steam generation. Steam demand must be calculated according to production rate and process conditions; the example for a 10 t/h line indicates approximately 500–600 kg/h before allowance for losses.

PELLETING: PRESSURE, DIE AND ROLL CONTROL

Pelleting transforms conditioned meal into compact particles through mechanical pressure and friction. Ring-die pellet mills are widely used, while flat-die systems are applied in specific applications.

The roll-to-die gap is an important operating parameter, with an indicative range of approximately 100–300 μm. Die temperature may reach approximately 95°C, depending on pressure and raw-material characteristics. Die compression ratio is expressed as:

CR = L ÷ D 

where L is the effective die-hole length and D is the hole diameter.

Typical die-hole diameters vary with animal species and product. Poultry-feed dies may commonly use approximately 3–4 mm, ruminant-feed dies approximately 6–8 mm, and some livestock applications may reach 12 mm. Fish-feed dies can start at approximately 1 mm, depending on product requirements. An example service life for a die is approximately 30,000 tonnes, although actual life depends strongly on raw materials, formulation, operating conditions, and maintenance.

Metal protection is also essential. A magnet installed before the pellet mill helps prevent metallic contamination from reaching the die and rolls, reducing the risk of severe equipment damage.

COOLING, CRUMBLING AND SIEVING

Fresh pellets may leave the press at approximately 80°C, with moisture commonly around 14–16%, and in some conditions reaching approximately 17%. Cooling reduces both temperature and moisture before storage or further processing. A practical target for final poultry-feed moisture is approximately 12–12.5%, while the final product temperature may be targeted at approximately ambient temperature ±5°C.

Cooling performance depends on the interaction between airflow, bed depth, production rate, discharge rate, and residence time. Increasing bed depth excessively can restrict airflow through the product, whereas excessive airflow through a shallow bed can cause over-cooling and unnecessary moisture loss. Therefore, airflow cannot be optimized independently from production rate and cooler loading.

Cooler performance should be evaluated using several parameters rather than outlet temperature alone: inlet and outlet temperature, moisture before and after cooling, moisture loss, production rate, product level, residence time, extracted-air quantity, static pressure, filter differential pressure, extracted fines, PDI, and water activity.

For young poultry, cooled pellets may pass through a crumbler to produce a smaller particle size. The relationship between cooling and crumbling is important: excessive moisture may produce soft and irregular crumble, while excessive drying may increase brittleness and fines.

Sieving then separates acceptable particles from fines and oversized material. Example quality targets include ≤10% fines below 1 mm, while particle-size distributions must be adapted to animal age and product specification. For example, an illustrative distribution for starter feed may contain approximately 70% of particles within 1–3 mm.

POST-PELLET LIQUID ADDITION AND PACKAGING

Some additives, particularly heat-sensitive ingredients, are better incorporated after pelleting. Drum coaters, paddle coaters, and vacuum coaters provide different approaches for applying liquids to cooled pellets.

Packaging requires precise control of feed rate, weighing, discharge, bag clamping, and sewing. Filling systems may use a single or double weigher. A two-weigher arrangement can improve throughput by allowing one side to fill while the other is being prepared. Fast and slow filling stages are commonly used: high flow provides rapid filling, followed by reduced flow near the target weight to improve accuracy. An example packaging tolerance is ±50 g, depending on product specification and weighing-system accuracy.

Bulk loading requires similar attention to weighing accuracy, material flow, dust collection, and segregation. Differences in particle size, density, and shape can cause segregation during transportation, storage, and loading.

SCADA AND INTEGRATED PROCESS CONTROL

Modern feed mills use SCADA (Supervisory Control and Data Acquisition) to connect material handling, dosing, grinding, mixing, conditioning, pelleting, cooling, crumbling, screening, and final discharge.

SCADA can monitor equipment status, temperatures, levels, alarms, discharge cycles, production sequences, and process parameters. In the cooler, for example, the system can display product temperature, sensor status, discharge-gate condition, and discharge frequency. Protective logic can stop upstream feeding when abnormal product accumulation occurs, preventing severe blockage and equipment damage.

The value of SCADA extends beyond automation: it creates a historical database that can be used to identify process losses, compare production shifts, investigate deviations, and establish meaningful performance indicators.

QUALITY CONTROL AND QUALITY ASSURANCE 

Feed quality requires both Quality Control (QC) and Quality Assurance (QA). Physical QC includes fines, particle-size distribution, hardness, and Pellet Durability Index (PDI). An indicative hardness range is approximately 3.5–4.5 kgf, depending on the measurement method. Chemical control includes moisture, protein, minerals, amino acids, and mycotoxins. A commonly referenced moisture range is 10–12%, while water activity may be approximately 0.5–0.7, depending on product and storage conditions.

Indicative analytical targets include protein deviation from formulation of approximately 0.5–1%, protein availability of ≥95%, aflatoxin of ≤20 ppb, and ochratoxin of ≤5 ppb, subject to the applicable product specification and market requirements. Particle-size analysis may use sieves such as 0.6, 1.0, 1.7, 2.8, and 3.3 mm. NIR analysis can provide rapid routine assessment when supported by appropriate calibration and laboratory validation.

QA extends beyond laboratory testing to pre-operational inspections, production documentation, maintenance procedures, warehouse controls, shipping, traceability, ISO 9001, and HACCP. Thus, quality must be built into the process rather than inspected only at the end.

MAINTENANCE, KPIs AND DATA-DRIVEN MANAGEMENT

Equipment reliability directly affects capacity, cost, and quality. MTBF (Mean Time Between Failures) is calculated as: 

MTBF = Operating Time ÷ Number of Failures 

while MTTR (Mean Time to Repair) is: 

MTTR = Corrective Maintenance Time ÷ Number of Repairs 

MTBF reflects reliability, whereas MTTR reflects the speed of restoring equipment after failure. Preventive-maintenance compliance, recurring failures, lubrication intervals, spare-parts consumption, and corrective-maintenance frequency should also be monitored.

Production performance can be summarized through Availability, Performance, and Quality:

Availability (%) = Operating Time ÷ Planned Time × 100

Performance (%) = Actual Rate ÷ Ideal Rate × 100

Quality (%) = Good Quantity ÷ Total Quantity × 100 

where: 

Good Quantity = Total Production − (Rework + Reject)

These indicators combine into:

OEE = Availability × Performance × Quality. 

Additional management indicators include Loss Tons, calculated as potential production minus actual good production; Rework; Compliance Rate; and Stock Coverage, calculated as available stock divided by daily demand. 

CONCLUSION

Efficient feed manufacturing depends on controlling the complete chain rather than optimizing isolated operations. Grinding determines particle characteristics; mixing determines uniformity; conditioning prepares the feed for pelleting; the die and rolls determine pellet formation; cooling controls final temperature and moisture; crumbling and screening determines particle distribution; packaging and transportation influence final integrity; and SCADA transforms process events into usable operational data.

The integration of process parameters, quality measurements, equipment reliability, maintenance indicators, production KPIs, inventory information, and management analysis creates a practical framework for continuous improvement. The objective is not simply maximum throughput, but stable production of the required feed specification with controlled variation, reliable equipment, efficient resource utilization, and traceable performance.

The fundamental principle is simple: control the process, measure the variation, understand the losses, and use the data to improve the next production cycle.