# Swine Feeding Management for Grow-Finish Pigs ## Key Takeaways - Grow-finish pig diets require phased nutrition, typically 3-4 diets with gradually decreasing lysine and crude protein levels (e.g., 1.15-1.30% lysine for early growers, 0.70-0.85% for late finishers) to match declining lean gain potential and optimize cost. - Feed intake is paramount, driven by feeder adjustment (maintaining 30-50% trough coverage), water availability (0.3-0.4 gallons per pound of feed), and appropriate stocking density (8-10 sq ft per pig for finishers). - Monitoring daily feed intake per pig and weekly feed conversion ratio (target 2.6-3.2 lbs feed/lb gain) are critical early warning systems for health or management issues, with deviations often preceding visible symptoms. - Water quality is crucial; high levels of total dissolved solids (>3000 ppm) or sulfates (>500 ppm) can reduce intake and performance, necessitating testing and potential treatment. - Mycotoxin contamination from moldy feed ingredients (e.g., DON, aflatoxin) significantly reduces feed intake and growth, requiring testing and the use of binders or dilution strategies. - Split-sex feeding, where gilts receive higher amino acid diets than barrows, can improve feed conversion by 3-5% by matching nutrient supply to sex-specific growth patterns. --- Feeding grow finish pigs is the most expensive part of pork production, often accounting for 65 to 75 percent of total production costs. This guide covers the complete grow-finish pig feeding program, from diet formulation and feed budgets to bunk management, water intake, and troubleshooting poor performance. It is written for swine producers, farm managers, and employees who want practical, field-ready guidance on swine grow finish nutrition and feeding management. ## At a Glance - Grow-finish phase typically covers pigs from 50 to 60 pounds up to market weight at 270 to 290 pounds. - Feed cost is the largest single expense in grow-finish production. Precision feeding and waste reduction directly improve profitability. - Pigs need separate diet phases during grow-finish. A typical program uses three to four diets with gradually declining lysine and crude protein levels. - Feed intake drives growth. Manage feeder adjustment, water availability, and pen stocking density to maximize intake. - Feed budget for a pig going from 55 to 285 pounds is roughly 700 to 800 pounds of feed, depending on genetics and diet energy. - Monitor daily feed intake per pig and [feed conversion ratio](/knowledge/animal-farming/poultry/feed-conversion-ratio-measuring-improving-poultry-efficiency) weekly. Changes in intake are early warning signs of health or management problems. - Water is the most important nutrient. Pigs need about 0.3 to 0.4 gallons of water per pound of feed consumed. - Mycotoxin risks, feed ingredient variation, and feeder adjustment are common causes of reduced intake and poor gain. - Work with a swine nutritionist to formulate diets for your specific genetics, facility type, and target market weight. ## Understanding the Grow-Finish Phase The grow-finish phase is the final stage of pork production. It begins when pigs leave the nursery and ends when they go to market. This phase covers a wide weight range, usually from about 50 pounds to 270 pounds or heavier depending on your packer and market. During this period, pigs undergo major changes in body composition. Early in the grow-finish phase, pigs deposit mostly lean tissue. As they approach market weight, the rate of lean deposition slows and fat deposition increases. This shift has direct consequences for diet formulation. Grower diets need higher amino acid concentrations to support muscle growth. Finisher diets can use lower amino acid levels because the pig's genetic potential for lean gain has declined. The grow-finish phase lasts about 16 to 20 weeks for most operations. The exact duration depends on your starting weight, genetics, diet quality, facility conditions, and target market weight. A typical growth curve shows pigs gaining about 1.8 to 2.2 pounds per day during this phase, with feed conversion ratio ranging from 2.6 to 3.2 pounds of feed per pound of gain. Understanding the biology of this phase helps you make better feeding decisions. Pigs have a limited daily feed intake capacity. As they grow, their intake increases, but not as fast as their body weight. This is why diet nutrient density must change over time. A diet that is adequate for a 60 pound pig is too concentrated for a 200 pound pig, and a diet that fits a 200 pound pig does not support maximum lean gain in a 60 pound pig. ## Diet Formulation for Grow-Finish Pigs ### Nutrient Requirements by Phase Swine grow finish nutrition is built around matching dietary nutrients to the pig's changing requirements. Most nutritionists divide the grow-finish period into phases. A common three phase program looks like this: | Phase | Weight Range | Lysine Level | Crude Protein | |---|---|---|---| | Early grower | 50 to 90 lbs | 1.15 to 1.30% | 18 to 20% | | Late grower | 90 to 150 lbs | 1.00 to 1.15% | 16 to 18% | | Early finisher | 150 to 220 lbs | 0.85 to 1.00% | 14 to 16% | | Late finisher | 220 lbs to market | 0.70 to 0.85% | 12 to 14% | These ranges are starting points. Your nutritionist will adjust them based on your pig genetics, feed ingredient prices, facility type, and target market weight. Some operations use more phases, especially in late finishing, to reduce feed costs without sacrificing performance. Lysine is the first limiting amino acid in swine diets. It is used as the reference for all other amino acid levels. Diets should be formulated on a standardized ileal digestible (SID) basis, not on total amino acid content. This ensures the pig actually absorbs the amino acids it needs. Other essential amino acids include threonine, methionine, tryptophan, valine, and isoleucine. These are typically balanced as ratios to lysine. For example, SID threonine is usually set at about 62 to 65 percent of SID lysine, and SID methionine plus cysteine at about 55 to 60 percent of lysine. Crystalline amino acids allow nutritionists to reduce crude protein levels while maintaining amino acid adequacy, which lowers diet cost and reduces nitrogen excretion. ### Energy Sources Corn is the primary energy source in most grow-finish diets. It provides starch, which is highly digestible and supports good feed intake. Corn also contributes some protein, oil, and fiber. The energy value of corn varies with growing conditions, storage, and processing. Other energy sources include: - Bakery meal and other food processing byproducts - Wheat and barley in regions where they are economical - Fat and oil additions to increase energy density - Distillers dried grains with solubles (DDGS) which provide energy, protein, and phosphorus Adding fat to finisher diets increases energy density and improves feed conversion. Common fat sources include choice white grease, poultry fat, and vegetable oils. Fat inclusion rates typically range from 2 to 6 percent of the diet. Higher fat levels can reduce feed intake slightly because pigs eat to meet their energy needs. This is acceptable if the diet is properly balanced. ### Protein Sources Soybean meal is the standard protein supplement in U.S. swine diets. It has an excellent amino acid profile and high digestibility. Other protein sources include canola meal, field peas, and synthetic amino acids. The goal is to meet the pig's amino acid requirements at the lowest cost per unit of gain. Soybean meal levels are highest in grower diets and decline as pigs move through the finish phases. This matches the pig's declining amino acid requirements. Using crystalline lysine, threonine, methionine, and tryptophan allows the nutritionist to reduce soybean meal inclusion and lower diet cost. ### Fiber and Gut Health Fiber levels in grow-finish diets have increased in recent years due to the use of DDGS and other byproducts. Moderate fiber levels are acceptable and may support gut health. However, high fiber levels reduce energy density and increase feed intake requirements. This can hurt feed conversion and increase gut fill at market weight. Typical total dietary fiber in grow-finish diets ranges from 3 to 5 percent for corn soybean meal diets and can reach 6 to 8 percent when DDGS is included at moderate levels. Avoid excessive fiber in late finisher diets because it increases the weight of intestinal contents, which can reduce carcass yield at the packer. ### Vitamins and Minerals Grow-finish diets require a complete vitamin and mineral premix. Key vitamins include vitamin A, D, E, K, and the B complex. Key minerals include calcium, phosphorus, sodium, chloride, potassium, zinc, copper, manganese, iron, and selenium. Calcium and phosphorus are critical for bone development. The calcium to phosphorus ratio should be about 1.1 to 1.25 to 1. Excess calcium can interfere with phosphorus absorption and reduce performance. Phytase enzymes are commonly added to release phosphorus from plant sources, reducing the need for supplemental inorganic phosphorus. Zinc and copper are important for immune function and growth. Pharmacological levels of zinc (2000 to 3000 ppm) and copper (125 to 250 ppm) have growth promoting effects, but these are being phased out in some markets due to environmental concerns. Work with your nutritionist to determine appropriate levels for your operation. ### Feed Additives Several feed additives are used in grow-finish diets to improve performance and health. These include: - Antibiotic growth promoters where still permitted - Probiotics and prebiotics for gut health - Organic acids for feed preservation and gut health - Enzymes such as phytase and xylanase - Mycotoxin binders when ingredient quality is uncertain - Feed flavoring agents to improve palatability Not all additives are justified in every operation. Work with your nutritionist and veterinarian to select additives that address specific needs in your herd. Track the cost of each additive against the expected return in performance or health. ## Developing a Pig Feeding Program ### Phase Feeding Strategies The number of diet phases in your grow-finish program depends on your facility design, feed system capacity, and management capability. More phases allow you to match diets more closely to pig requirements, which reduces feed cost and nutrient excretion. However, more phases require additional feed bins, more diet changeovers, and more careful management. A standard three phase program works well for many operations. A four phase program allows a more gradual reduction in amino acid levels in late finishing. Some operations use as many as six to eight phases, especially when feed prices are high and the value of precision feeding justifies the extra management. The key is to change diets at the right pig weights. Do not change diets based on calendar dates alone. Pig weights vary within a barn, and the average weight may not reflect the true nutritional needs of the group. Weigh pigs at each diet change to confirm the group is on track. ### Split Sex Feeding Barrows and gilts have different growth patterns and nutrient requirements. Barrows eat more, gain faster, and deposit more fat. Gilts have a higher lean gain potential and are more efficient. Split sex feeding allows you to feed each sex a diet that matches its requirements. In a split sex program, gilts receive a higher amino acid diet than barrows at the same weight. This supports their greater lean growth potential. Barrows receive a lower amino acid diet, which reduces cost and prevents excess fat deposition. The performance advantage of split sex feeding is typically 3 to 5 percent improvement in feed conversion and lean gain. Split sex feeding requires separate pens and separate feed systems for barrows and gilts. If your facility does not support this, you can still sort pigs by sex at placement and feed the same diet to both. The benefit is reduced but still positive. ### Precision Feeding Precision feeding is an emerging approach that adjusts diet composition daily or weekly based on the pig's predicted requirements. This is different from phase feeding, which uses a few fixed diets. Precision feeding can reduce feed cost by 5 to 10 percent and nitrogen excretion by 20 to 30 percent compared to conventional phase feeding. Precision feeding requires automated feeding systems that can mix and deliver multiple diets. It also requires accurate growth models and real time weight estimation. This technology is becoming more common in large operations but is not yet practical for all producers. A simpler approach is to increase the number of diet phases and change diets more frequently. This captures some of the benefits of precision feeding without the investment in automated systems. ### Diet Changeover Procedures Changing diets too quickly can cause a drop in feed intake. Pigs need time to adjust to a new diet, especially if the ingredient composition changes significantly. Follow these steps for smooth diet transitions: 1. Mix the new diet before the old diet runs out completely. This allows feed in the bin to blend naturally during the transition. 2. When possible, use a transition diet that is a blend of the old and new diets. Feed the blend for two to three days before switching completely. 3. Check feeder adjustment after each diet change. Feed flow characteristics can change with diet composition, especially with fat or fiber additions. 4. Monitor feed intake for two to three days after the change. A slight dip is normal, but a sustained drop indicates a problem. 5. Record the date and pig weight at each diet change for your records. ## Feed Budgets and Cost Management ### Calculating Feed Needs A feed budget tells you how much feed you need for a group of pigs from placement to market. This helps with feed purchasing, bin capacity planning, and cost projections. To calculate a feed budget, you need three numbers: - Starting weight - Target market weight - Expected feed conversion ratio The formula is simple: Feed needed = (Target weight minus starting weight) multiplied by feed conversion ratio For example, if pigs start at 55 pounds, go to 285 pounds, and have a feed conversion of 2.9, the feed needed is: (285 minus 55) multiplied by 2.9 = 230 multiplied by 2.9 = 667 pounds per pig Add 3 to 5 percent for feed waste and spillage. This brings the budget to about 685 to 700 pounds per pig. Actual feed conversion varies with genetics, health status, diet quality, facility conditions, and management. Track your own feed conversion over time to build accurate budgets for your operation. ### Feed Cost per Pig Feed cost per pig is the product of feed per pig and average feed price. If feed costs $0.10 per pound and pigs need 700 pounds, feed cost is $70 per pig. This is the single largest cost in grow-finish production. To reduce feed cost per pig, focus on two levers: 1. Reduce feed conversion ratio through better management and health 2. Reduce diet cost per ton through ingredient selection and formulation Both levers matter. A small improvement in feed conversion can save more money than a small reduction in diet cost, because feed conversion affects every pound of feed the pig eats. ### Ingredient Price Monitoring Feed ingredient prices fluctuate. Corn and soybean meal prices are the main drivers of feed cost. Monitor these prices weekly and work with your nutritionist to adjust formulations when prices shift. When corn prices are high, consider: - Using more byproduct feeds such as DDGS or bakery meal - Reducing diet energy density slightly - Feeding more phases to avoid overfeeding amino acids When soybean meal prices are high, consider: - Using more crystalline amino acids to reduce soybean meal inclusion - Using alternative protein sources - Reducing crude protein levels while maintaining amino acid adequacy The best formulation depends on current prices and the nutrient content of available ingredients. Your nutritionist can run least cost formulations to find the cheapest diet that meets the pig's requirements. ## Feeding Systems and Equipment ### Types of Feeders Several types of feeders are used in grow-finish barns. The right choice depends on your facility, group size, and management style. Dry feeders are the most common. They store feed in a hopper and deliver it to a trough as pigs eat. Dry feeders can be single sided or double sided. Single sided feeders are placed along a wall or pen divider. Double sided feeders serve two pens and are placed between pens. Wet dry feeders mix feed and water in the trough. Pigs eat a wet mash rather than dry feed. Wet dry feeders can improve feed intake and reduce dust, but they require careful adjustment to prevent feed waste. Liquid feeding systems mix feed with water and deliver a slurry through pipes. These systems are common in Europe and are gaining interest in the United States. Liquid feeding allows the use of liquid byproducts such as whey and can improve feed efficiency. However, these systems have higher capital costs and require careful management to prevent feed spoilage. ### Feeder Adjustment Feeder adjustment is one of the most important management tasks in grow-finish barns. A poorly adjusted feeder either restricts intake or allows excessive feed waste. Both problems reduce profitability. The goal is to keep about 30 to 50 percent of the feeder trough bottom covered with feed. If the trough is empty, pigs are restricted and intake drops. If the trough is overflowing, feed is being wasted. Check feeders daily and adjust them based on feed coverage. The adjustment mechanism varies by feeder type. Most feeders have a flow gate or agitator that controls feed delivery. Turn the adjustment down slightly when feed accumulates, and up when the trough runs empty. Feed wastage is a hidden cost. A 5 percent feed waste rate on a barn that uses 700 pounds of feed per pig adds 35 pounds of wasted feed per pig. At $0.10 per pound, that is $3.50 per pig in wasted feed. On a 1000 head barn, that is $3500 per turn. ### Feed Storage and Delivery Feed bins should be checked regularly for bridging, mold, and insect infestation. Bridging occurs when feed forms a crust and does not flow into the auger. This restricts feed delivery and can cause pigs to go without feed. Inspect bins before each load of feed is delivered. Clean out old feed and remove any caked material. Check bin vents and lids to prevent water entry. Moisture in feed bins promotes mold growth and mycotoxin production. Feed delivery systems should be checked for wear and proper operation. Augers that run too fast can damage feed and create fines. Fines accumulate in feeders and reduce intake. Use a fines elimination system or adjust auger speed to minimize fines. ## Water Intake and Management ### Water Requirements Water is the most important nutrient for pigs. Grow-finish pigs need about 0.3 to 0.4 gallons of water per pound of feed consumed. A pig eating 5 pounds of feed per day needs 1.5 to 2.0 gallons of water. A pig eating 7 pounds of feed per day needs 2.1 to 2.8 gallons. Water intake is closely tied to feed intake. If water is restricted, feed intake drops. This directly reduces growth rate and increases days to market. Ensure pigs always have access to clean, fresh water. ### Water Quality Water quality affects intake and health. Test your water supply at least annually for minerals, bacteria, and nitrates. Key parameters to check include: - Total dissolved solids below 3000 ppm - Nitrate nitrogen below 10 ppm - Sulfate below 500 ppm - Iron below 0.3 ppm - Hardness below 300 ppm - Coliform bacteria below 1 colony per 100 mL High mineral levels can reduce water intake and cause diarrhea. Sulfate levels above 1000 ppm are especially problematic and can cause loose stools and reduced performance. If water quality is poor, consider water treatment or an alternative water source. ### Water Delivery Systems Nipple drinkers are the most common water delivery system in grow-finish barns. They should be adjusted to the right height for pig size. For grow-finish pigs, nipples should be at shoulder height of the smallest pig in the pen. Water flow rate is critical. Nipple drinkers should deliver at least 1 cup (8 ounces) per minute for grower pigs and 2 cups per minute for finisher pigs. Low flow rates restrict intake and reduce performance. Check water delivery systems daily. Look for leaks, blocked nipples, and low pressure. Clean water lines regularly to prevent biofilm buildup. Water medication systems should be checked and calibrated before each use. Placement of drinkers matters. At least one drinker should be within 10 feet of the feeder. Pigs eat and drink in cycles, and they prefer to drink near where they eat. Drinkers should be placed away from dunging areas to maintain water quality. ## Feeder Space and Pen Management ### Feeder Space Requirements Feeder space affects intake and performance. Too little feeder space restricts intake, especially for the most aggressive pigs. Too much feeder space wastes pen space and can increase feed waste. A common recommendation is one feeder space per 4 to 5 pigs for single sided feeders and one per 8 to 10 pigs for double sided feeders. A feeder space is roughly 12 to 15 inches of trough length per pig. Monitor pigs at the feeder to check for crowding. If pigs are waiting to eat, feeder space is inadequate. If feed is being wasted, feeder space may be excessive. ### Stocking Density Stocking density affects feed intake and growth. Pigs housed at high density have reduced feed intake and slower growth. They also have more aggressive interactions and greater variation in performance. For pigs up to 100 pounds, provide at least 6 to 7 square feet per pig. For pigs from 100 to 150 pounds, provide 7 to 8 square feet. For pigs over 150 pounds, provide 8 to 10 square feet. These are minimum recommendations. More space is better for performance, especially in hot weather. In fully slatted floors, space requirements are slightly lower than in solid floor barns. However, do not reduce space below the minimums listed above without good reason. ### Environmental Effects on Intake Temperature and ventilation affect feed intake. Pigs are comfortable in a narrow temperature range. The thermoneutral zone for grow-finish pigs is roughly 60 to 75 degrees Fahrenheit, depending on pig weight and air speed. When temperatures rise above the thermoneutral zone, pigs reduce feed intake to lower heat production. This reduces growth rate. At 85 degrees, feed intake can drop by 10 to 20 percent. At 95 degrees, intake can drop by 30 percent or more. Cooling strategies include: - Increasing air speed over pigs with fans - Using drip coolers or sprinklers - Providing more floor space per pig - Feeding during cooler parts of the day - Increasing diet nutrient density to compensate for lower intake Cold temperatures increase maintenance energy needs. Pigs eat more but gain less efficiently. Provide bedding or heat lamps if needed in cold weather. Adjust diet energy content to match the environmental conditions. ## Monitoring Performance ### Daily Feed Intake Track daily feed intake per pig. This is the most sensitive indicator of pig health and management. A drop in intake often precedes visible signs of disease by one to two days. To calculate daily feed intake per pig, weigh feed deliveries to the barn and subtract feed remaining. Divide by the number of pigs. Compare this number to your expected intake curve. Expected intake varies with pig weight. A 60 pound pig eats about 3 to 4 pounds per day. A 120 pound pig eats about 5 to 6 pounds per day. A 200 pound pig eats about 6 to 7 pounds per day. A 270 pound pig eats about 7 to 8 pounds per day. If intake drops by more than 5 percent from the previous day, investigate the cause. Check feeders, water, ventilation, and pig health. Early intervention prevents small problems from becoming large ones. ### Feed Conversion Ratio Feed conversion ratio is pounds of feed per pound of gain. It is calculated by dividing total feed consumed by total weight gain. Track this weekly for each barn. Feed conversion is affected by: - Genetics - Health status - Diet quality - Environmental conditions - Feed waste - Weight range A feed conversion of 2.7 to 2.9 is typical for grow-finish pigs in good conditions. Values above 3.2 indicate a problem. Investigate causes and take corrective action. ### Average Daily Gain Average daily gain is pounds of gain per day. Calculate it by dividing total weight gain by the number of pig days. Track this weekly as well. Expected average daily gain for grow-finish pigs is 1.8 to 2.2 pounds per day. Values below 1.5 indicate a problem. Values above 2.4 are excellent. Weigh pigs at placement, at each diet change, and at market. Use a scale that is accurate and calibrated. Weigh a sample of 5 to 10 percent of pigs if you cannot weigh the entire group. ### Growth Curves Plot your pigs' weight against age to create a growth curve. This helps you identify when growth is below expectation. It also helps you plan diet changes and market dates. A typical growth curve shows pigs gaining weight at a steady rate through the grow-finish phase. Deviations from the curve indicate problems. Investigate any group that falls more than 5 percent below the expected curve. ## Common Feeding Mistakes ### Overfeeding Amino Acids Feeding more amino acids than pigs need is a waste of money. Excess amino acids are deaminated and excreted as urea. This costs energy and increases nitrogen excretion. Use the lowest amino acid level that supports the desired growth rate. Work with your nutritionist to fine tune amino acid levels for your genetics and management system. ### Underfeeding Amino Acids Underfeeding amino acids reduces lean gain and increases fat deposition. Pigs may look healthy but carry excess fat at market weight. This reduces carcass value and feed efficiency. Signs of amino acid deficiency include: - Reduced growth rate - Increased backfat - Reduced feed intake - Poor feed conversion If you see these signs, check diet formulations and feed delivery. Confirm pigs are getting the correct diet for their weight. ### Ignoring Feed Waste Feed waste is a silent profit killer. A 5 to 10 percent waste rate is common in poorly managed barns. This adds 35 to 70 pounds of wasted feed per pig. Check feeders daily and adjust them properly. Repair damaged feeders promptly. Consider wet dry feeders if waste is a persistent problem. Train employees to watch for feed waste and correct it immediately. ### Changing Diets Too Quickly Pigs need time to adjust to diet changes. A sudden change can cause a drop in intake and a mild digestive upset. This reduces performance for several days. Use transition diets when possible. Blend old and new diets over two to three days. Monitor intake closely after each change. ### Using Poor Quality Ingredients Feed ingredient quality varies. Moldy corn, rancid fat, and heat damaged soybean meal reduce intake and performance. Test ingredients for quality before use. Check for mold and mycotoxins, especially in years with poor growing conditions. Store feed ingredients properly to prevent spoilage. Use mycotoxin binders when ingredient quality is uncertain. ### Inconsistent Feeding Schedules Pigs thrive on routine. Inconsistent feeding schedules cause stress and reduce intake. Feed at the same times each day. Keep feed in the feeder at all times. If you use restricted feeding, be consistent with the amount and timing. Changes in feeding schedule can cause digestive upset and aggressive behavior. ## Troubleshooting Poor Performance ### Low Feed Intake Low feed intake is the most common cause of poor growth in grow-finish pigs. When intake drops, gain drops and days to market increase. Check these factors in order: 1. Feeder adjustment. Is feed accessible to pigs? 2. Water supply. Are drinkers working and delivering adequate flow? 3. Feed palatability. Does the feed smell or taste normal? 4. Environmental temperature. Is the barn too hot or too cold? 5. Health status. Are pigs showing signs of disease? 6. Stocking density. Are pigs overcrowded? Correct the most likely cause first. Monitor intake for 24 to 48 hours to confirm improvement. ### Poor Feed Conversion Poor feed conversion means pigs are eating more than expected for the gain they produce. This is often caused by feed waste, but it can also result from health problems or environmental stress. Check feed waste first. Weigh feed delivered to the barn and compare to feed consumed. Inspect feeders for leaks and overflow. Then check pig health and environmental conditions. ### Variable Pig Weights Variable weights within a pen are common but can be reduced with good management. Causes include: - Inadequate feeder space - Aggressive pigs dominating feeders - Health problems in individual pigs - Inconsistent feed delivery Sort pigs by weight at placement. Remove sick or slow growing pigs to a hospital pen. Provide adequate feeder and floor space for all pigs. ### Pigs Going Off Feed A sudden drop in feed intake across a barn is a red flag. It often signals a disease outbreak or a feed quality problem. Check feed quality first. Look for mold, off odors, or changes in ingredient composition. Then check water supply and environmental conditions. If no cause is found, contact your veterinarian. ## Mycotoxin Management ### Common Mycotoxins in Swine Feed Mycotoxins are toxic compounds produced by molds that grow on feed ingredients. They are a common cause of reduced feed intake and poor performance in grow-finish pigs. Key mycotoxins affecting swine include: - Aflatoxin, produced by Aspergillus species - Deoxynivalenol (DON or vomitoxin), produced by Fusarium species - Zearalenone, produced by Fusarium species - Fumonisin, produced by Fusarium species - Ochratoxin, produced by Penicillium and Aspergillus species Each mycotoxin has different effects. Aflatoxin causes liver damage and immune suppression. DON causes feed refusal and vomiting. Zearalenone causes reproductive problems in gilts. Fumonisin affects the lungs and liver. ### Testing Feed for Mycotoxins Test feed ingredients and complete feeds for mycotoxins, especially in years with drought, excess rain, or poor storage conditions. Use a reputable laboratory that specializes in mycotoxin analysis. Sampling is critical. Mycotoxins are not evenly distributed in grain. Take multiple samples from different locations in the bin or truck. Mix samples thoroughly and submit a representative subsample to the lab. ### Managing Contaminated Feed If mycotoxin levels exceed safe thresholds, take action: 1. Dilute contaminated grain with clean grain to reduce toxin levels 2. Add mycotoxin binders to reduce absorption 3. Increase diet nutrient density to compensate for reduced intake 4. Monitor pig performance closely Mycotoxin binders include clay products such as bentonite and aluminosilicates, as well as yeast cell wall products. Binders are not equally effective for all mycotoxins. Select a binder that targets the specific toxin you are dealing with. ### Preventing Mycotoxin Problems Prevention is better than treatment. Follow these practices: - Harvest grain at proper moisture and dry it quickly - Store grain at 13 to 14 percent moisture or lower - Keep storage bins clean and free of old grain - Control insects and rodents in storage areas - Rotate grain inventory to use older grain first - Inspect feed bins regularly for moisture and mold ## Feed Ingredient Quality Assurance ### Evaluating Corn Quality Corn quality affects pig performance and feed cost. Key factors include: - Moisture content, target below 15 percent - Test weight, target above 54 pounds per bushel - Broken kernels and foreign material - Mold and mycotoxin contamination - Storage time and conditions High moisture corn requires more drying and can spoil during storage. Low test weight corn has less energy per bushel. Broken kernels are more susceptible to mold and reduce feed quality. ### Evaluating Soybean Meal Quality Soybean meal quality varies with processing. Key factors include: - Crude protein content, typically 46 to 48 percent - Urease activity, an indicator of proper heat processing - Particle size and uniformity - Color and odor Under processed soybean meal has low urease activity and contains antinutritional factors. Over processed meal has reduced lysine availability. Test soybean meal regularly to ensure quality. ### Using Byproduct Feeds Byproduct feeds can reduce diet cost but require careful management. Common byproducts include: - Distillers dried grains with solubles (DDGS) - Bakery meal - Wheat middlings - Rice bran - Corn gluten feed Byproducts vary in nutrient content and quality. Test each load before use. Introduce byproducts gradually to allow pigs to adapt. Monitor performance closely when byproduct inclusion rates change. DDGS deserves special attention. It is high in protein, fat, and phosphorus, but it is also high in fiber and variable in quality. Typical inclusion rates in grow-finish diets range from 10 to 30 percent. Higher rates can reduce feed intake and increase manure volume. ## Record Keeping for Feeding Management ### What to Record Good records are essential for managing feed costs and pig performance. Track the following for each barn or group: - Pig numbers and weights at placement - Diet formulations and feed deliveries - Feed consumption by phase - Pig weights at each diet change - Pig weights at market - Feed conversion ratio - Average daily gain - Feed cost per pig - Health treatments and mortality Record this information daily or weekly. Use a spreadsheet or a commercial record keeping system to organize the data. ### Analyzing Records Review records at least monthly. Compare current performance to historical averages and to your targets. Look for trends that indicate problems. Key questions to ask: - Is feed intake per pig on target? - Is feed conversion improving or worsening? - Are pigs reaching market weight on schedule? - Is feed cost per pig within budget? - Are any barns or groups performing below average? Use this analysis to make adjustments. Small improvements in feed conversion or days to market have a large impact on profitability. ### Using Records for Decision Making Records help you make better decisions about diet formulations, feeder management, and market timing. For example, if feed conversion has worsened over several groups, investigate the cause. It may be time to adjust the feeding program or improve feeder management. Records also help you evaluate new products and practices. Compare performance before and after a change to determine if the change was beneficial. ## When to Call a Veterinarian or Extension Agent ### Signs That Require Veterinary Attention Contact your veterinarian if you see any of these signs: - Sudden drop in feed intake across multiple pens - Multiple pigs showing signs of respiratory disease - Pigs with diarrhea, vomiting, or neurological signs - Mortality above 1 to 2 percent per month - Pigs that are reluctant to stand or move - Any unusual signs that you cannot explain Early veterinary intervention reduces the impact of disease outbreaks. Do not wait until the problem is severe. ### Working with Your Veterinarian Your veterinarian should be part of your feeding management team. They can help you: - Diagnose health problems that affect feed intake - Adjust diets for sick or recovering pigs - Develop treatment protocols for common diseases - Review feed additive programs - Monitor antimicrobial use and resistance Share your feeding records with your veterinarian. This information helps them understand what is happening in your herd. ### When to Contact an Extension Agent Extension agents and swine specialists can help with feeding management questions that are not health related. Contact them for help with: - Diet formulation and feed budgeting - Feed ingredient evaluation - Mycotoxin management - Facility design for feeding systems - Economic analysis of feeding programs - Interpreting feed test results Extension specialists have access to current research and can connect you with other producers facing similar challenges. Many states have swine extension specialists who provide free or low cost assistance. ### Preparing for a Consultation Before calling your veterinarian or extension agent, gather the following information: - Pig numbers and weights - Feed intake data for the last week - Diet formulations and feed delivery records - Water quality test results - Environmental conditions in the barn - Treatment records and mortality data The more information you provide, the better advice you will receive. Do not wait until the problem is severe to seek help. ## Frequently Asked Questions ### How much feed does a grow-finish pig eat per day? A grow-finish pig eats about 3 to 4 pounds of feed per day at 60 pounds, increasing to 6 to 7 pounds per day at 200 pounds, and 7 to 8 pounds per day at 270 pounds. Daily feed intake depends on genetics, diet energy density, environmental temperature, and health status. Track your own intake patterns to establish a baseline for your operation. ### What is a good feed conversion ratio for grow-finish pigs? A feed conversion ratio of 2.7 to 2.9 pounds of feed per pound of gain is typical for grow-finish pigs in good conditions. Genetics, health status, diet quality, and feed waste all affect feed conversion. Values above 3.2 indicate a problem that needs investigation. ### How many diet phases should I use in the grow-finish period? Most operations use three to four diet phases during grow-finish. More phases allow you to match diets more closely to pig requirements, which reduces feed cost and nutrient excretion. The number of phases you can use depends on your feed system capacity and management ability. ### Should I feed barrows and gilts separately? Split sex feeding allows you to feed each sex a diet that matches its requirements. Gilts need higher amino acid levels than barrows. The performance advantage is typically 3 to 5 percent improvement in feed conversion and lean gain. This practice requires separate pens and feed systems. ### How often should I adjust feeders? Check feeders daily and adjust them based on feed coverage in the trough. The goal is to keep about 30 to 50 percent of the trough bottom covered with feed. Adjust the flow gate or agitator as needed to maintain this coverage. ### What causes pigs to go off feed suddenly? Sudden feed refusal can be caused by feed quality problems, water restriction, heat stress, or disease outbreaks. Check feed for mold or off odors first. Then check water supply and environmental conditions. If no cause is found, contact your veterinarian. ### How do I know if my water quality is adequate for pigs? Test your water supply at least annually for minerals, bacteria, and nitrates. Key parameters include total dissolved solids below 3000 ppm, nitrate nitrogen below 10 ppm, sulfate below 500 ppm, and coliform bacteria below 1 colony per 100 mL. High mineral levels reduce water intake and can cause diarrhea. ### What should I do if I suspect mycotoxin contamination in my feed? Test the feed for mycotoxins immediately. If toxin levels exceed safe thresholds, dilute contaminated grain with clean grain, add mycotoxin binders, and monitor pig performance closely. Work with your nutritionist and veterinarian to manage contaminated feed safely. ## Related Farming Guides This section will be populated with links to related farming guides on swine production, including nursery pig management, sow feeding programs, and pork marketing strategies. ## Related Clinical & Scientific Guides * [Pig Enrichment Programs and Behavior Monitoring](/knowledge/animal-farming/swine/pig-enrichment-programs-and-behavior-monitoring) * [Swine Handling Facility Design for Safe Pig Movement](/knowledge/animal-farming/swine/swine-handling-facility-design-safe-pig-movement) * [Pig Farm Cost of Production Records](/knowledge/animal-farming/swine/pig-farm-cost-of-production-records) ## References - National Pork Board: https://www.pork.org/ - USDA APHIS Swine Health: https://www.aphis.usda.gov/livestock-poultry-disease/swine - FAO Pig Production: https://www.fao.org/pig-production-and-products/en/ - FAO Animal Production and Health: https://www.fao.org/animal-production/en/ - WOAH (World Organisation for Animal Health): https://www.woah.org/en/home/ > This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.