# Nursery Pig Feed Formulation and Nutrient Requirements ## Key Takeaways - Nursery pig digestive systems are immature at weaning, necessitating highly digestible ingredients like dried whey, plasma protein, and specialty soy products in early diets (Phase 1) to support gut health and nutrient absorption during the critical first 5-10 days post-weaning. - Energy density should be high initially (1,500-1,550 kcal/lb DE) and gradually decrease as pigs grow, while standardized ileal digestible (SID) lysine requirements decline from approximately 1.50% in Phase 1 to 1.15% in the final nursery phase. - Phase feeding, utilizing 5-7 distinct diets from weaning to 60 lbs, is crucial for matching nutrient complexity to the pig's evolving digestive capacity, thereby optimizing growth, minimizing feed cost per pound of gain, and reducing nutrient excretion. - Water is a critical nutrient; early nursery pigs require approximately 0.5 gallons/day, increasing to 1.5 gallons/day by the end of the nursery phase, with water quality and consistent access being paramount drivers of feed intake. - Pharmacological levels of zinc oxide (2,000-3,000 ppm) are commonly used for the first 10-14 days post-weaning to mitigate diarrhea and support intake, though regulatory restrictions are leading to reduced levels or alternative strategies. --- Nursery pig feed formulation is one of the most financially and biologically sensitive decisions a swine producer makes. The nursery phase, typically covering pigs from weaning at about 3 to 4 weeks of age through 10 to 12 weeks of age, sets the trajectory for lifetime growth performance, health, and carcass quality. This guide covers the nutrient requirements of nursery pigs, the principles of phase feeding, practical feed formulation strategies, common formulation mistakes, and monitoring practices. It is written for independent producers, farm managers, feed mill operators, and students of swine nutrition who need a working reference for making sound feeding decisions. ## At a Glance - Nursery pigs need 5 to 7 distinct diet phases from weaning to about 60 pounds body weight. - Weaned pigs have immature digestive systems. Feed intake in the first week after weaning is the single biggest driver of nursery success. - Digestible energy density should start high, around 1,500 to 1,550 kcal/lb (3,300 to 3,400 kcal/kg), and decline as pigs grow. - Lysine is the first limiting amino acid. Standardized ileal digestible (SID) lysine requirements range from about 1.50% in phase 1 down to about 1.15% in the final nursery phase. - Complex ingredients such as dried whey, fish meal, plasma protein, and specialty soy products support intake and gut health in the first two phases. - Phase feeding matches diet complexity to the pig's changing digestive capacity and reduces feed cost per pound of gain. - Water is a nutrient. Pigs need about 0.5 gallons per day in early nursery, rising to 1.5 gallons by the end of the phase. - Feed budget per pig weaned is roughly 60 to 80 pounds of complete feed across all nursery phases. - Antibiotic-free and reduced-zinc programs require extra attention to ingredient quality, feed processing, and barn hygiene. - Work with a swine nutritionist or extension specialist to validate formulations and adjust for your specific genetics and health status. ## Understanding Nursery Pig Digestive Development The nursery phase is defined by a dramatic transition in the pig's digestive system. At birth, the piglet relies on sow milk, which is highly digestible and rich in fat and lactose. The digestive enzymes needed to break down complex carbohydrates and plant proteins are present only at low levels at birth. They increase gradually over the first several weeks of life. At weaning, typically 18 to 28 days of age, the pig is suddenly expected to consume dry feed. This feed contains complex starches, plant proteins, and fibers that the pig's digestive system is not yet fully equipped to handle. The result is a period of low feed intake, reduced growth, and increased susceptibility to diarrhea and other digestive disturbances. This post-weaning growth lag is normal to some degree, but good feed formulation minimizes its duration and severity. The small intestine undergoes physical and chemical changes in the first week after weaning. The villi, which are fingerlike projections that absorb nutrients, shorten and become less efficient. The crypts, where new cells are produced, deepen. This remodeling takes 5 to 10 days. During this time, the pig's ability to digest and absorb nutrients is reduced. Feed formulation for the first nursery phase must account for this temporary impairment by using highly digestible ingredients. Enzyme production also shifts. Lactase, the enzyme that digests lactose from milk, declines after weaning. However, the pig retains some ability to use lactose for several weeks. Pancreatic enzymes such as amylase, trypsin, and chymotrypsin increase gradually. By about 6 to 8 weeks of age, the pig can handle a mostly corn and soybean meal diet. By 10 to 12 weeks, the digestive system is functionally mature for a growing pig. Gastric acidity is another factor. Young pigs produce limited stomach acid, which reduces protein digestion and allows harmful bacteria to survive. Acidifiers such as organic acids are sometimes added to nursery diets to support protein digestion and gut health. ## Nutrient Requirements for Nursery Pigs Nutrient requirements for nursery pigs are expressed on a standardized ileal digestible (SID) basis for amino acids. This system accounts for the fact that not all protein in feed ingredients is digested and absorbed by the pig. Using SID values allows more accurate formulation and reduces excess nitrogen excretion. ### Energy Energy is the foundation of the nursery diet. Weaned pigs need high energy density to support rapid growth and to compensate for the low feed intake typical in the first week after weaning. The primary energy sources in nursery diets are corn, fat or oil, dried whey, and specialty protein ingredients. Recommended digestible energy (DE) values by phase are approximately: - Phase 1 (weaning to 7 days): 1,500 to 1,550 kcal/lb (3,300 to 3,400 kcal/kg) - Phase 2 (7 to 21 days post-weaning): 1,480 to 1,530 kcal/lb (3,260 to 3,370 kcal/kg) - Phase 3 (21 to 42 days post-weaning): 1,450 to 1,500 kcal/lb (3,200 to 3,300 kcal/kg) - Phase 4 (42 to 63 days post-weaning): 1,420 to 1,470 kcal/lb (3,130 to 3,240 kcal/kg) Adding 2% to 5% fat or oil increases energy density and reduces dust. Common choices are choice white grease, poultry fat, and vegetable oil. Fat quality matters. Rancid fat reduces feed intake and can destroy fat-soluble vitamins. ### Protein and Amino Acids Amino acids are the building blocks of muscle. Lysine is the first limiting amino acid in corn and soybean meal based diets. All other amino acid requirements are expressed relative to lysine. The ideal protein concept states that amino acids should be supplied in the exact proportions the pig needs for maintenance and growth. SID lysine recommendations by phase are approximately: - Phase 1: 1.45% to 1.55% - Phase 2: 1.35% to 1.45% - Phase 3: 1.25% to 1.32% - Phase 4: 1.12% to 1.20% These values assume average genetics and moderate health status. High health herds with superior genetics may benefit from levels at the upper end of the range. Low health herds or challenging environments may see no benefit from higher lysine because other factors limit growth. Other critical amino acids and their SID ratios relative to lysine for nursery pigs are approximately: - Threonine: 60% to 64% - Methionine plus cysteine: 56% to 60% - Tryptophan: 17% to 19% - Valine: 66% to 70% - Isoleucine: 52% to 56% Synthetic amino acids allow diet formulation to meet these ratios precisely. L-lysine HCl, DL-methionine, L-threonine, and L-tryptophan are commonly used. Valine and isoleucine products are available but are used less frequently because typical diets meet requirements with adequate intact protein. Crude protein levels in nursery diets typically range from 18% to 22%. Excess protein increases nitrogen excretion and can contribute to ammonia levels in the barn. Formulating to SID amino acid requirements rather than crude protein minimums reduces waste and supports gut health. ### Calcium and Phosphorus Calcium and phosphorus are critical for bone development and many metabolic functions. Nursery pig requirements are expressed as available phosphorus or standardized total tract digestible (STTD) phosphorus. Recommended levels by phase are approximately: - Calcium: 0.80% to 0.90% in phase 1, declining to 0.65% to 0.75% by phase 4 - STTD phosphorus: 0.45% to 0.50% in phase 1, declining to 0.38% to 0.42% by phase 4 The calcium to phosphorus ratio should be maintained between 1.1:1 and 1.25:1. Excess calcium can reduce phosphorus absorption and form insoluble complexes with other minerals. Phytase is an enzyme that releases phosphorus from plant ingredients. Most commercial nursery diets include phytase at levels that reduce the need for inorganic phosphorus supplementation. When using phytase, follow the manufacturer's matrix values for phosphorus release and adjust calcium accordingly. Over-supplementation of calcium in phytase diets reduces enzyme efficacy. ### Trace Minerals Zinc and copper are the trace minerals of greatest interest in nursery nutrition. Both have roles beyond simple nutrient deficiency. At pharmacological levels, they support growth and reduce diarrhea. Zinc oxide is commonly added at 2,000 to 3,000 ppm zinc for the first 10 to 14 days after weaning. This practice reduces the incidence and severity of post-weaning diarrhea and supports feed intake. However, high zinc levels are increasingly restricted by regulation in some regions due to environmental concerns. Many producers now use lower levels, around 1,000 to 1,500 ppm, or use alternative strategies. Copper is added at 100 to 250 ppm in nursery and grower diets. At these levels, copper acts as a growth promoter. Copper sulfate is the most common source. Copper also has antimicrobial properties in the gut. Other trace minerals required in nursery diets include iron, manganese, iodine, and selenium. Iron is particularly important for nursing pigs but is less critical in the nursery phase because most pigs receive an iron injection at birth. Selenium is typically added at 0.30 ppm. Organic trace mineral sources are more bioavailable than inorganic sources but are more expensive. They are often used at lower inclusion rates. ### Vitamins Nursery pigs require all fat-soluble vitamins (A, D, E, K) and the B-complex vitamins. Commercial vitamin premixes are designed to meet requirements with a margin of safety. Typical nursery vitamin premix inclusion is 0.10% to 0.25% of the diet. Vitamin E is of particular interest because it supports immune function. Levels of 40 to 100 IU per pound of feed are common in nursery diets. Vitamin D is critical for calcium and phosphorus metabolism. The use of 25-hydroxy vitamin D3 is increasing because it is more efficiently utilized than standard vitamin D3. Biotin and folic acid are sometimes added at higher levels for hoof health and growth, though research support for these additions in nursery diets is limited. ### Water Water is the most essential nutrient and is often overlooked in feed formulation discussions. Weaned pigs need immediate access to clean, fresh water. Water intake drives feed intake. Pigs that do not drink do not eat. Estimated water requirements by phase are: - Phase 1: 0.3 to 0.6 gallons per pig per day - Phase 2: 0.5 to 1.0 gallons per pig per day - Phase 3: 0.8 to 1.3 gallons per pig per day - Phase 4: 1.0 to 1.6 gallons per pig per day Water quality matters. High mineral content, bacterial contamination, or poor palatability reduces intake. Test water sources annually and after any change in source. Provide at least one nipple drinker per 10 pigs and position drinkers at the correct height for pig size. ## Phase Feeding Programs for Nursery Pigs Phase feeding is the practice of changing diet formulations as pigs grow to match their changing nutrient requirements and digestive capacity. This approach reduces feed cost, improves growth performance, and minimizes nutrient excretion. A typical nursery phase feeding program uses 4 to 7 diets. The exact number depends on barn turnover, feed delivery systems, and management preferences. More phases allow closer matching of nutrients to requirements but create more feed changes and inventory complexity. ### Phase 1: The Weaning Diet Phase 1 is fed for the first 5 to 10 days after weaning. Its purpose is to encourage immediate feed intake and support the transitioning gut. This is the most expensive diet on a per ton basis and the most important for setting up the rest of the nursery period. Key characteristics of a phase 1 diet: - High digestibility ingredients such as dried whey, spray-dried plasma, fish meal, and specialty soy protein concentrate - High lactose content, typically 15% to 25% - Low crude fiber - Added zinc oxide at pharmacological levels unless restricted - Acidifiers such as formic, citric, or fumaric acid - Flavoring agents to enhance palatability - Fine grinding of ingredients Spray-dried plasma is one of the most effective ingredients for supporting feed intake and reducing diarrhea in newly weaned pigs. It is expensive, typically 10% to 20% of the phase 1 diet. It provides immunoglobulins that offer passive protection against pathogens. Dried whey provides lactose, which is highly palatable and easily digested. Lactose also promotes the growth of beneficial lactic acid bacteria in the gut. A phase 1 diet with 15% to 25% dried whey is standard. Some producers use higher levels when weaning very young pigs. Fish meal provides high quality protein with an excellent amino acid profile. It is highly palatable and digestible. Inclusion rates of 3% to 8% are common in phase 1 and phase 2 diets. Use only high quality, low ash fish meal to avoid off flavors and excess minerals. Specialty soy products such as soy protein concentrate, fermented soybean meal, or enzyme-treated soybean meal are used to replace some or all of the conventional soybean meal in early nursery diets. These products have reduced levels of antinutritional factors that can cause digestive upset in young pigs. ### Phase 2: The Transition Diet Phase 2 is typically fed from about day 7 to day 21 post-weaning. Pigs are consuming more feed and their digestive systems are adapting. Diet complexity decreases but remains higher than grower diets. Key characteristics of a phase 2 diet: - Reduced lactose, typically 10% to 15% - Reduced plasma protein, typically 0% to 5% - Increased soybean meal, up to 20% to 25% of the diet - Continued use of fish meal at 3% to 5% - Zinc oxide may be reduced to 1,000 to 1,500 ppm - Acidifiers and flavors may be reduced or eliminated The goal of phase 2 is to transition pigs from highly digestible specialty ingredients to a more conventional corn and soybean meal based diet while maintaining growth and gut health. ### Phase 3: The Grower-Nursery Diet Phase 3 is typically fed from about day 21 to day 42 post-weaning. Pigs weigh approximately 25 to 40 pounds. The digestive system is now capable of handling a mostly corn and soybean meal diet. Key characteristics of a phase 3 diet: - Lactose eliminated or reduced to 5% or less - Conventional soybean meal as the primary protein source - Fish meal eliminated or reduced to 2% to 3% - Added fat at 2% to 4% - Standard trace mineral and vitamin premises - No pharmacological zinc oxide unless specifically needed ### Phase 4: The Pre-Grower Diet Phase 4 is optional but common in operations that feed multiple nursery diets. It is typically fed from about day 42 to day 63 post-weaning, taking pigs from 40 to 60 pounds. This diet is very similar to an early grower diet. Key characteristics of a phase 4 diet: - Corn and soybean meal as the primary ingredients - 1% to 3% added fat - Amino acid supplementation to reduce crude protein - Standard mineral and vitamin levels for growing pigs Some operations skip phase 4 and move pigs directly to a grower diet at 40 to 50 pounds. This works well when the grower diet is well formulated and the transition is managed carefully. ### Alternative Phase Feeding Schedules Some producers use a simpler 3-phase program, particularly in smaller operations or when feed delivery systems limit the number of diets. A 3-phase program might be: - Phase 1: Weaning to 14 days - Phase 2: 14 to 35 days post-weaning - Phase 3: 35 days to 60 pounds Other producers use a 6 or 7 phase program, especially in high health herds with superior genetics where maximizing growth is the priority. Each additional phase allows a closer match of nutrients to requirements but adds complexity and cost. The decision on number of phases should be based on: - Barn capacity and pig flow - Feed delivery and storage capacity - Labor availability - Genetic potential of the pigs - Health status of the herd - Feed cost and ingredient availability ## Step-by-Step Guide to Formulating Nursery Pig Diets Feed formulation requires a systematic approach. The following steps provide a practical framework for developing nursery diets. Work with a swine nutritionist or use a reputable feed formulation software program for the actual calculations. ### Step 1: Define the Target Pig and Performance Goals Start by defining the weight range, age, genetic potential, and health status of the pigs. Establish clear performance goals for average daily gain, feed efficiency, and mortality. These goals guide nutrient specifications. For example, a typical nursery goal might be: - Weaning weight: 12 to 14 pounds at 21 days of age - Nursery exit weight: 55 to 60 pounds at 63 days of age - Average daily gain: 0.7 to 0.9 pounds per day - Feed efficiency: 1.3 to 1.5 pounds of feed per pound of gain - Mortality: less than 2% ### Step 2: Select the Phase Feeding Program Decide on the number of phases and the weight or day ranges for each phase. Consider your feed delivery system, storage capacity, and labor. A 4-phase program is a good starting point for most operations. ### Step 3: Establish Nutrient Specifications For each phase, establish target levels for: - Digestible energy - SID lysine and other essential amino acids - Calcium and STTD phosphorus - Trace minerals and vitamins - Lactose and specialty ingredient inclusions - Maximum crude fiber Use the values provided in this guide as starting points. Adjust based on your genetics, health status, and performance goals. ### Step 4: Select Ingredients Choose ingredients based on availability, cost, quality, and suitability for the phase. Common nursery ingredients include: - Corn or other cereal grains - Soybean meal (conventional or specialty) - Dried whey - Spray-dried plasma - Fish meal - Fat or oil - Synthetic amino acids - Dicalcium phosphate or monocalcium phosphate - Limestone - Salt - Vitamin and trace mineral premises - Phytase and other feed enzymes - Acidifiers - Zinc oxide and copper sulfate Ingredient quality is critical. Test incoming ingredients for moisture, protein, and key nutrients. Reject ingredients that show signs of spoilage, mold, or contamination. ### Step 5: Calculate the Diet Use a feed formulation program to calculate the diet that meets all nutrient specifications at the lowest cost. The program will solve for ingredient inclusion rates while meeting all constraints. If formulating manually, use a spreadsheet. Start with the major ingredients, then add supplements to meet requirements. Check all nutrients, not just the ones you targeted. Excesses of some nutrients can be as problematic as deficiencies. ### Step 6: Review and Adjust Review the finished formulation for practical issues: - Does the diet have acceptable pellet quality or meal texture? - Are ingredient inclusions within practical limits? - Is the cost per ton reasonable for the phase? - Does the diet meet all nutrient requirements without excesses? Make adjustments as needed. Small changes in ingredient inclusion can have significant effects on cost and performance. ### Step 7: Test and Monitor Feed the new diet to a group of pigs and monitor performance. Compare actual results to your goals. Watch for signs of poor palatability, digestive upset, or reduced growth. Adjust formulations based on what you observe. ## Ingredient Selection and Quality Control Ingredient quality varies widely and directly affects nursery pig performance. Poor quality ingredients reduce feed intake, cause digestive upset, and increase the risk of disease. Implement a quality control program for all feed ingredients. ### Corn and Cereal Grains Corn is the primary energy source in most nursery diets. It should be clean, dry, and free from mold and mycotoxins. Test corn for moisture, test weight, and mycotoxin levels. Reject corn with more than 15% moisture or visible mold. Grinding corn to the proper particle size is critical. Nursery diets should be ground to 600 to 700 microns for meal diets and 500 to 600 microns for pelleted diets. Fine grinding increases digestibility but creates dust and can cause stomach ulcers if too fine. ### Soybean Meal Conventional soybean meal contains antinutritional factors that can cause digestive upset in young pigs. Use only high quality, properly processed soybean meal. Look for a light color, uniform particle size, and no burnt or toasted odor. For phase 1 and phase 2 diets, consider using specialty soy products that have been processed to reduce antinutritional factors. These products are more expensive but support better performance in young pigs. ### Dried Whey Dried whey is a byproduct of cheese production. It provides lactose and high quality protein. Quality varies by source. Look for a consistent cream to light tan color and a sweet, clean odor. Reject whey that is brown, clumped, or has an off odor. Lactose content of dried whey is typically 65% to 75%. The protein content is about 11% to 12%. Dried whey is highly hygroscopic, meaning it absorbs moisture. Store it in a dry area and use it quickly after opening. ### Spray-Dried Plasma Spray-dried plasma is produced from porcine or bovine blood. It is highly palatable and provides immunoglobulins that support gut health. It is the most expensive ingredient in nursery diets. Quality varies significantly by source. Look for a consistent light color and a clean, slightly sweet odor. Reject plasma that is dark, clumped, or has a burnt odor. Store in a cool, dry place and use within 6 months of production. ### Fish Meal Fish meal provides high quality protein with an excellent amino acid profile. Quality varies by fish species, processing method, and storage. Use only high quality, low ash fish meal. Look for a consistent brown color and a fishy but not rancid odor. Reject fish meal that is dark, has a strong ammonia odor, or shows signs of insect infestation. Fish meal can oxidize and become rancid, which reduces palatability and destroys vitamins. ### Fats and Oils Added fat increases energy density and reduces dust. Common sources include choice white grease, poultry fat, and vegetable oil. Fat quality is critical. Rancid fat reduces feed intake and can destroy fat-soluble vitamins. Test fats for free fatty acids, peroxide value, and moisture. Reject fats with high free fatty acids or peroxide values. Store fats in clean, sealed containers and use within 30 days of delivery. ### Synthetic Amino Acids Synthetic amino acids allow precise formulation and reduce crude protein levels. L-lysine HCl, DL-methionine, L-threonine, and L-tryptophan are commonly used. These products are highly concentrated and consistent in quality. Check the concentration of the active ingredient. L-lysine HCl is typically 78.8% lysine. Methionine products vary in concentration. Store in a dry area and use before the expiration date. ### Feed Enzymes Phytase is the most common enzyme in nursery diets. It releases phosphorus from plant ingredients, reducing the need for inorganic phosphorus. Other enzymes such as xylanase and beta-glucanase are sometimes added to improve energy digestibility. Follow the manufacturer's recommendations for inclusion rates and matrix values. Store enzymes according to manufacturer instructions. Most are stable in feed for 30 to 60 days. ## Feed Processing for Nursery Pigs Feed processing affects nutrient digestibility, feed intake, and health. The two main processing options for nursery diets are meal and pellets. ### Meal Diets Meal diets are simpler and less expensive to produce. The key to a good meal diet is uniform particle size. Grind corn to 600 to 700 microns and mix thoroughly. Poor mixing can cause nutrient segregation and variable intake. Meal diets are more dusty than pellets, which can increase respiratory issues in the barn. Adding 1% to 2% fat or oil reduces dust. Some producers also add molasses or other binding agents. ### Pelleted Diets Pelleting improves feed efficiency by 3% to 8% compared to meal diets. The heat and pressure of pelleting gelatinizes starch, which improves digestibility. Pellets also reduce waste and dust. The downside of pelleting is cost. Pelleting adds expense for equipment, energy, and labor. Pellets can also be too hard or too soft, which affects intake. Feed mills need to adjust steam and pressure settings for nursery diets. For nursery pigs, pellets of 3/16 inch diameter are appropriate. Avoid fines, which reduce intake and increase waste. A good pellet has less than 10% fines. ### Feed Form and Intake The form of feed affects intake, particularly in the first days after weaning. Some producers use a crumbled pellet for phase 1, which is a pellet that has been broken into smaller pieces. Crumbs are easier for small pigs to eat than whole pellets. Other producers use a gruel or slurry feeding system, where feed is mixed with water before feeding. This can improve intake in the first days after weaning but requires additional equipment and labor. ## Common Mistakes in Nursery Pig Feed Formulation Many feeding problems trace to avoidable formulation errors. The following are the most common mistakes observed on farms. ### Mistake 1: Skimping on Phase 1 Diet Quality The phase 1 diet is the most expensive diet in the nursery program, but it is also the most important. Cutting corners on ingredient quality or nutrient levels in phase 1 reduces intake, slows recovery from weaning stress, and increases the risk of diarrhea. The cost of a poor phase 1 diet is not just in the nursery phase. Pigs that start poorly often never fully catch up. They reach market weight later, have lower average daily gain throughout the grow-finish phase, and may have poorer feed efficiency. Do not reduce plasma, whey, or specialty soy levels below recommended ranges to save cost. Instead, look for savings in later phases where ingredient quality matters less. ### Mistake 2: Abrupt Diet Changes Pigs need time to adapt to diet changes. Abrupt switches from a complex phase 1 diet to a simple phase 2 diet can cause a drop in intake and digestive upset. This is often called a "post-weaning lag" but it can happen at any diet transition. Manage transitions by: - Mixing old and new diets for 2 to 3 days - Using a transition diet that is intermediate in complexity - Monitoring intake daily during transitions - Ensuring fresh, clean water is always available Some operations use a "bridge" diet that is fed between phases. This adds complexity but can smooth transitions and maintain performance. ### Mistake 3: Ignoring Water Quality and Access Water is the most important nutrient, yet it is often the most neglected. Poor water quality, insufficient drinker space, or incorrect drinker height all reduce water intake, which reduces feed intake. Test water for: - Total dissolved solids (TDS) below 3,000 ppm is acceptable, below 1,000 ppm is ideal - Nitrate nitrogen below 10 ppm - Sulfate below 500 ppm - Iron below 0.3 ppm - Bacterial contamination, especially coliforms Provide at least one drinker per 10 pigs. Position drinkers at shoulder height of the smallest pig in the pen. Clean drinkers regularly and check flow rates. A nipple drinker should deliver 0.5 to 1.0 quart per minute. ### Mistake 4: Over-Supplementing or Under-Supplementing Minerals Mineral imbalances cause a range of problems. Excess calcium reduces phosphorus absorption and can cause rickets. Excess zinc can interfere with copper absorption. Copper deficiency causes anemia and poor growth. Follow recommended mineral levels and use quality premixes. If you add extra minerals for specific reasons, such as pharmacological zinc, understand the risks and monitor pig performance. ### Mistake 5: Poor Ingredient Quality Control Using moldy corn, rancid fat, or degraded protein sources wastes money and harms pigs. Mycotoxins in moldy corn reduce feed intake, damage the liver, and suppress immunity. Rancid fat destroys vitamins and reduces palatability. Test ingredients regularly and reject those that do not meet quality standards. Store ingredients properly to prevent spoilage. Use a first in, first out inventory system. ### Mistake 6: Formulating for Average Pigs Only A feed formulation based on average requirements assumes all pigs are the same. In reality, pigs vary in weight, health, and growth potential. A formulation that meets the needs of the average pig will under-feed some and over-feed others. Consider the variation in your herd. If you wean pigs at a wide range of ages and weights, consider sorting into weight groups and feeding different diets. This is not always practical, but it can improve overall performance. ### Mistake 7: Neglecting Feed Budgets A feed budget is a plan for how much feed each pig will consume in each phase. Without a budget, it is easy to run out of a phase 1 diet or to feed phase 2 too long. Typical feed budgets per pig weaned: - Phase 1: 5 to 8 pounds - Phase 2: 15 to 20 pounds - Phase 3: 25 to 35 pounds - Phase 4: 30 to 40 pounds Adjust these budgets based on your actual performance. Monitor feed usage and adjust orders accordingly. ## Decision Thresholds and When to Adjust Formulations Not every growth problem is a nutrition problem. Before changing formulations, determine the cause of poor performance. The following decision framework helps distinguish nutritional issues from other problems. ### Feed Intake Below Expectations If feed intake is below expectations in the first week after weaning, check: - Water availability and quality - Feeder adjustment and accessibility - Barn temperature and drafts - Health status of the pigs - Diet palatability If water, environment, and health are adequate, consider diet palatability. Pigs may reject feed with rancid fat, poor quality protein, or excessive mineral levels. Try adding a flavoring agent or switching to a different feed form. ### Diarrhea in Nursery Pigs Diarrhea in the nursery phase has many causes. Before changing feed, rule out infectious causes. Work with your veterinarian to diagnose the cause. Nutritional causes of diarrhea include: - Excess protein, particularly poor quality protein - Excess lactose - Excess minerals, particularly magnesium and potassium - Mycotoxins - Abrupt diet changes - Poor ingredient quality If diarrhea is associated with a recent diet change, consider going back to the previous diet and transitioning more slowly. If diarrhea persists, have the feed tested for mycotoxins and nutrient content. ### Poor Growth Without Diarrhea If pigs are eating well but not growing, the diet may be deficient in energy or amino acids. Check: - Actual nutrient levels versus formulated levels - Feed intake per pig per day - Average daily gain versus goals - Feed efficiency If intake is adequate but gain is poor, increase energy density or amino acid levels. If intake is low, address palatability or environmental issues first. ### When to Call a Veterinarian or Extension Agent You should call a veterinarian if you observe: - Sudden increases in mortality or morbidity - Diarrhea that does not respond to dietary changes within 48 hours - Neurological signs such as tremors, incoordination, or paralysis - Respiratory distress - Skin lesions or discoloration - Any signs of a notifiable disease You should call an extension agent or swine nutritionist if you observe: - Persistent poor growth without an obvious cause - Feed intake that is consistently below targets - Feed efficiency that is consistently worse than targets - Difficulty formulating diets or selecting ingredients - Questions about new regulations affecting feed additives ## Monitoring and Recordkeeping Good recordkeeping is essential for evaluating feed formulation success. Without records, you cannot know whether changes are helping or hurting. ### Key Records to Maintain Maintain the following records for each group of nursery pigs: - Weaning date and average weaning weight - Feed budget and actual feed delivered by phase - Feed intake per pig per day by week - Average daily gain by week - Feed efficiency by phase - Mortality and culling rates by week - Medication and treatment records - Water intake if meters are available - Barn temperature and ventilation settings - Diet formulations and ingredient sources ### Using Records to Improve Formulations Review records at the end of each nursery group. Compare actual performance to goals. Identify phases where performance was below expectations and investigate causes. Look for patterns across groups. If the same phase consistently underperforms, the formulation may need adjustment. If problems appear only in certain seasons, environmental factors may be involved. ### Feed Sampling and Analysis Sample feed regularly to verify nutrient content. Take samples from the feeder or feed line, not just from the bag or bulk bin. Submit samples to a commercial feed testing laboratory for analysis. Test for: - Moisture - Crude protein - Calcium and phosphorus - Key amino acids if concerns exist - Mycotoxins if mold is suspected - Particle size for meal diets Compare test results to formulation targets. Investigate any significant deviations. ## Economics of Nursery Pig Feed Formulation Feed is the largest cost in nursery pig production, typically 60% to 70% of total nursery costs. Feed formulation decisions directly affect profitability. ### Cost per Ton versus Cost per Pound of Gain The cheapest diet per ton is not always the most economical. A more expensive diet that improves feed efficiency or average daily gain can reduce the cost per pound of gain. Calculate the cost per pound of gain for each phase: Cost per pound of gain = Feed cost per pound x Feed efficiency For example, if a diet costs $0.15 per pound and feed efficiency is 1.4, the cost per pound of gain is $0.21. If a more expensive diet costs $0.17 per pound but improves feed efficiency to 1.3, the cost per pound of gain is $0.221. The cheaper diet is more economical in this case. ### Value of Early Growth Growth in the nursery phase has a compounding effect on later performance. Pigs that are heavier at the end of the nursery phase tend to reach market weight sooner and may have better feed efficiency in the grow-finish phase. Research on this topic is limited and results vary, but many producers find that investments in nursery nutrition pay off in reduced days to market. Consider the value of earlier market weight when evaluating nursery feed costs. ### Ingredient Price Volatility Feed ingredient prices fluctuate significantly. Corn, soybean meal, and specialty ingredients all vary in price. A formulation that is economical today may not be economical next month. Work with your feed supplier or nutritionist to review formulations regularly and adjust for ingredient price changes. Consider alternative ingredients when prices are favorable. ## Special Considerations for Antibiotic-Free and Reduced Zinc Programs Consumer demand and regulatory pressure are driving changes in nursery pig nutrition. Many producers are raising pigs without antibiotics or with reduced levels of zinc oxide. These programs require extra attention to nutrition and management. ### Antibiotic-Free Programs Removing antibiotics from nursery diets requires a comprehensive approach: - Start with high health pigs from disease-free herds - Optimize the environment to reduce stress - Use high quality, highly digestible ingredients - Consider alternative feed additives such as organic acids, probiotics, prebiotics, and plant extracts - Monitor health closely and intervene early if problems arise Organic acids such as formic, citric, and benzoic acid are commonly used in antibiotic-free programs. They reduce the pH of the gut, which inhibits harmful bacteria and supports protein digestion. Probiotics and prebiotics support beneficial gut bacteria. Results vary by product and farm. Work with a nutritionist to select products with research support. ### Reduced Zinc Programs Zinc oxide at pharmacological levels is increasingly restricted in some regions. Producers need alternative strategies for supporting gut health after weaning. Options include: - Lower levels of zinc oxide (1,000 to 1,500 ppm) combined with other gut health strategies - Copper at higher levels (150 to 250 ppm) - Organic acids - Probiotics and prebiotics - Plant extracts such as oregano oil and garlic - Improved barn hygiene and management These strategies are not as effective as pharmacological zinc in supporting growth, but they can be effective when combined with good management. ## Frequently Asked Questions ### What is the ideal weaning age for nursery pigs? Most commercial operations wean pigs at 19 to 24 days of age. Weaning before 18 days requires more complex and expensive nursery diets. Weaning after 28 days reduces the number of litters per sow per year and may not be economical. The ideal weaning age depends on your facility, health status, and management capabilities. If you wean at a younger age, plan for a longer phase 1 with higher levels of plasma, whey, and specialty protein ingredients. ### How much feed does a nursery pig eat per day? Feed intake depends on age, weight, and diet palatability. In the first 3 days after weaning, intake may be very low, often less than 0.2 pounds per pig per day. By the end of the first week, intake should rise to about 0.5 to 0.8 pounds per day. By the end of the nursery phase at 55 to 60 pounds, intake is typically 3.0 to 3.5 pounds per pig per day. Monitor intake daily in the first week after weaning, as low intake is the most common cause of poor nursery performance. ### Should I use pelleted or meal feed for nursery pigs? Pelleting improves feed efficiency by 3% to 8% and reduces waste and dust. The heat of pelleting also gelatinizes starch, which improves digestibility. The main disadvantage is cost. Pelleting adds expense for equipment, energy, and labor. For phase 1 and phase 2 diets, many producers use crumbled pellets, which are easier for small pigs to eat. For later phases, either form works well. If you use meal diets, grind corn to 600 to 700 microns and mix thoroughly. ### How do I know if my nursery diet has too much or too little protein? Signs of excess protein include increased water intake, wetter manure, higher ammonia levels in the barn, and potentially more diarrhea. Excess protein increases nitrogen excretion, which is an environmental concern. Signs of protein deficiency include poor growth, reduced feed intake, and pale pigs. The best approach is to formulate to SID amino acid requirements rather than crude protein levels. Test feed regularly to verify protein and amino acid content. ### What is the difference between SID and total amino acid requirements? SID stands for standardized ileal digestible. It represents the portion of an amino acid that is digested and absorbed by the pig, accounting for the basal endogenous losses from the digestive tract. Total amino acid values include both digestible and indigestible portions. Formulating to SID values is more accurate because it accounts for differences in ingredient quality. Most modern feed formulation programs use SID values. If you are using total amino acid values, your formulations will be less precise and may have excess or deficiency of some amino acids. ### How long should I feed the phase 1 diet? Feed phase 1 for 5 to 10 days after weaning. The exact duration depends on the age and weight of the pigs at weaning and their intake. Younger and lighter pigs need a longer phase 1. Monitor intake and pig condition. If pigs are eating well and gaining weight, you can transition to phase 2 at day 5 to 7. If intake is low or pigs are struggling, extend phase 1 to day 10. Never skip phase 1 or transition abruptly, as this will cause a growth lag. ### Can I add extra zinc oxide to my nursery diet? Zinc oxide at 2,000 to 3,000 ppm is effective at reducing diarrhea and supporting growth in the first 10 to 14 days after weaning. However, high zinc levels are increasingly restricted by regulation in some regions due to environmental concerns. Excess zinc is excreted in manure and can accumulate in soil. Check your local regulations before using pharmacological zinc levels. If you use high zinc, limit it to the first 2 weeks after weaning and work with your nutritionist to manage the transition when zinc is reduced. ### What should I do if my nursery pigs are not eating? First, check water availability and quality. Pigs that do not drink will not eat. Check the temperature of the barn. Pigs that are too cold will huddle and not eat. Pigs that are too hot will reduce intake. Check feeder adjustment and make sure feed is accessible. If the environment is adequate, check the feed itself. Is it fresh? Does it smell or look different from previous batches? Has the ingredient source changed? Consider adding a flavoring agent or offering a small amount of highly palatable feed to stimulate intake. If intake does not improve within 24 hours, contact your veterinarian to rule out disease. ## Related Farming Guides This section will be populated with links to related farming guides. Check back for updates on nursery pig management, grower-finisher feed formulation, sow nutrition, and swine health management. ## 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) * [Swine Feeding Management for Grow-Finish Pigs](/knowledge/animal-farming/swine/swine-feeding-management-for-grow-finish-pigs) ## 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.