Nursery Pig Management After Weaning

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-07-12

Key Takeaways

Post-weaning stress significantly compromises gut function and immunity: The transition from sow's milk to solid feed, coupled with social mixing and environmental changes, creates a critical vulnerability period that necessitates proactive management to mitigate poor growth and disease.
Optimal environmental control is paramount for piglet thermoregulation and health: Maintaining a precise temperature gradient (starting at 28-30°C at pig level and decreasing weekly) and ensuring adequate ventilation (minimizing ammonia levels below 25 ppm) are crucial for preventing cold stress, which suppresses feed intake and immune response.
Immediate and consistent access to clean water and palatable feed is non-negotiable: Dehydrated pigs will not eat, and stale feed deters intake; therefore, functional drinkers at the correct height and highly palatable starter diets, offered frequently in the first 24 hours, are essential for initiating positive growth.
All-in, all-out (AIAO) management and rigorous sanitation are critical for pathogen control: AIAO systems, combined with thorough cleaning, drying, and disinfection between groups, effectively break pathogen cycles, preventing the transmission of infectious agents to immunologically naïve piglets.
Systematic daily observation and detailed record-keeping are vital for early problem detection: Daily pen-level observation of pig behavior, manure consistency, and individual outliers, alongside meticulous recording of mortality, feed use, and treatments, enables prompt intervention and identifies underlying management or health issues.
Phase-feeding strategies and stable social groupings mitigate digestive and social stress: Gradual transitions between complex, highly digestible starter diets and simplified formulations, along with minimizing mixing of unfamiliar groups, support gut adaptation and reduce fighting, injury, and stress.

Weaning is the most stressful transition in a pig's life. In the space of hours, a piglet loses its mother, is mixed with unfamiliar animals, moves to a new environment, and must switch from sow's milk to solid or semi-solid feed. Each of these stressors independently suppresses gut function and immunity; together they create a period of vulnerability that, without careful management, results in poor growth, post-weaning diarrhea, and elevated mortality.

Good nursery management is not primarily about treatment,it is about reducing the biological cost of weaning by arriving with healthy piglets, providing a warm, clean, and well-ventilated environment, ensuring immediate access to water and palatable starter feed, and detecting problems before they escalate. The WOAH Terrestrial Animal Health Code chapter on pig welfare identifies thermal comfort, feed and water access, appropriate stocking density, and prompt care of sick animals as welfare requirements that apply in the nursery phase as much as anywhere else in pig production.

At a Glance

Management area	Key target	Common failure
Temperature	28,30 °C at arrival; reduce by ~2 °C per week	Cold pigs pile, stop eating, and are immunologically suppressed
Water	Functional drinkers at correct height from day 1	Dehydrated pigs will not eat; drinker height or flow rate prevents access
Feed introduction	Highly palatable starter at nose height; multiple feedings in first 24 hours	Feed left in troughs >24 hours becomes stale, is refused, and drives poor starts
Grouping	Keep litter or farrowing-room groups where possible; stable social groups	Mixing many sources creates fighting, injury, and stress
Daily observation	Walk each pen; note dull pigs, poor-doers, diarrhea, and injuries daily	Delayed response to sick pigs is the main driver of avoidable mortality
Sanitation	All-in all-out with thorough cleaning and dry-down between groups	Residual pathogens on wet surfaces initiate infection in immunologically naïve pigs
Records	Weight at placement, mortality, removals, feed use, treatments	Performance data reveal management or health problems that are invisible during daily rounds

The First 24 Hours After Placement

The single most important management action in the nursery is ensuring every pig drinks water within hours of placement. Pigs that are dehydrated will not eat, and pigs that do not eat in the first 24 hours begin the nursery phase in an energy deficit that impairs gut development and immune function. Check that:

Drinkers are functional, at the correct height for the size of pig being placed, and flow at an adequate rate. Nipple drinkers set too high or with a flow rate below what pigs need discourage use.
Water is clean. Biofilm, organic matter, or poor taste reduces intake; flush lines before placing pigs.
At least 10% of the pen's pigs are observed drinking within the first few hours. If many pigs cannot find the drinker, train them by tapping the nipple or using a temporary bowl drinker until pigs are oriented.

Place a highly palatable starter,typically a complex diet with milk products or other ingredients that encourage intake,in the feeder before pigs arrive. Offer fresh feed multiple times on day 1 so that troughs appear active; stale or bridged feed is a significant barrier to early intake. For some batches, small amounts scattered on a mat or the floor near the feeder can help orient pigs to the feed source. Iowa State University Extension's post-weaning nutrition and management guidance provides practical context on phase-feeding programs and feed form decisions for newly weaned pigs.

Environment: Temperature and Ventilation

Newly weaned pigs have limited thermoregulatory capacity and a high surface area relative to body mass. At placement, the lower critical temperature is approximately 28,30 °C, depending on pig size, floor type, and group size. A pig that is cold will divert metabolic energy to heat production rather than growth, will pile with pen mates (increasing injury and pathogen transmission risk), and will reduce feed intake.

Temperature targets should be established at pig level, not at ceiling level. Measure floor temperature or air temperature at pig height and adjust heating accordingly. As pigs grow and their thermoregulatory capacity improves, reduce target temperatures gradually,approximately 2 °C per week is a practical guide, but observe pig behavior as the primary signal: pigs that are piled at the back of the pen are cold; pigs that are spread out along cool walls may be too hot.

Ventilation and temperature are interdependent. Minimum ventilation is needed at all times to remove moisture, ammonia, and carbon dioxide, even in cold weather. However, excess ventilation in cold weather chills pigs. The Penn State Extension guide on pig barn ventilation and thermal comfort explains how to balance these goals through inlet management, fan staging, and controllers. Ammonia above approximately 25 ppm damages the respiratory epithelium and impairs mucociliary clearance,a biological defense system that is already under pressure in recently weaned pigs.

Feed Transition and Phase Feeding

A nursery pig's digestive system is adapted to sow milk at weaning. The shift to a cereal-based diet requires time for enzyme development, gut architecture changes, and microbiome adjustment. Abrupt transitions to high-cereal, low-protein, or poorly formulated diets during this adjustment window increase the risk of post-weaning diarrhea and depressed growth.

Most commercial nursery programs use a multi-phase feeding strategy:

Phase 1 (days 1,14 post-weaning): A complex, highly digestible starter with milk products, high-quality protein sources, and palatability-enhancing ingredients. Expensive per unit, but fed in small quantities.
Phase 2 (days 14,28 approximately): A simplified starter with lower milk product inclusion, transitioning toward more conventional ingredients.
Phase 3 (days 28 through nursery exit): A grower diet suitable to carry pigs to transfer weight, typically 25,30 kg depending on the system.

Phase transitions should be gradual: blend the outgoing and incoming feed for a few days rather than switching overnight. Feed a swine nutritionist should review phase formulations and transition timing for your specific pig source, target weights, and ingredient costs. Avoid arbitrary ingredient substitutions between phases; changes to protein source, digestibility, or inclusion of in-feed additives authorized through your veterinary plan should be made with professional input.

Water and feed access must be assessed together. An adequate feeder space allowance,typically 4,6 pigs per feeder hole for dry feeders,prevents competition that suppresses intake in lower-ranking pigs. Check feeder adjustment to minimize waste without restricting access.

Grouping and Social Management

Where possible, keep litters or farrowing-room groups together at weaning. Mixing pigs from multiple sows or multiple rooms increases the time pigs spend fighting to establish social hierarchy, which suppresses feed intake, causes injuries, and concentrates stress in the period already most biologically vulnerable.

When mixing is necessary,for example, to equalize group sizes or combine small litters,mix at the time of weaning rather than days later. Pigs placed together at weaning in an unfamiliar environment tend to settle more quickly than pigs that have already established a hierarchy in one group and are then mixed into another. Minimize the number of sources mixed into a single pen.

Sort by weight or size where practical. A pen with a wide weight range at placement is likely to have a widening tail of poor-doers by nursery exit, as small pigs lose competition for feed and social position to larger pen mates. If sorting occurs, ensure pens remain appropriately stocked.

Daily Observation Routine

Walk every pen every day and record what you observe. Signs of problems in nursery pigs are often visible before pigs reach a critical point, but only if observation is systematic and compared against a baseline.

Each walkthrough should check:

Pen behavior and distribution. Are pigs active and spread through the pen, or piled, lethargic, or pressing against walls?
Manure consistency. Loose or watery manure in a pen requires immediate investigation and recording of affected pigs.
Individual outliers. Any pig that is visibly smaller than pen mates, is lethargic, has sunken flanks, or shows visible injury should be identified, assessed, and either treated or moved to a hospital pen.
Water and feed. Is the feeder active? Are drinkers flowing?
Environmental conditions. Temperature, ventilation, and any unusual sounds from equipment.

Document findings in a pen or room log. Mortality must be recorded with cause, age, and weight where feasible. The National Pork Board's PQA+ program outlines the daily observation and treatment-authorization standards expected in commercial US pork production, including documentation requirements for treatments administered.

Sanitation and All-In All-Out Flow

Moving pigs through the nursery on an all-in all-out basis,where all pigs enter a room at the same time and leave before any new pigs arrive,is the single most effective management tool for breaking pathogen cycles between successive groups. A room that has pigs of multiple ages carries a continuous pool of pathogens that older, immune pigs shed while infecting younger, naïve arrivals.

Cleaning must be systematic to be effective. The sequence is: remove all organic matter, wash with detergent, rinse, allow to dry completely, and then disinfect. Wet or incompletely cleaned surfaces dramatically reduce disinfectant efficacy. Downtime between groups should be sufficient for thorough drying,this is as important as the disinfectant contact time. The University of Minnesota Extension swine resources include guidance on cleaning protocols for nursery facilities.

Do not allow partial fills or rolling admission to rooms designed for all-in all-out management. If batch size does not match room capacity, adjust production scheduling or physical room dividers rather than compromising the biosecurity design of the flow.

Performance Records and Targets

Nursery performance benchmarking requires consistent data collection. At minimum, record:

Placement date, number placed, and average or total placement weight
Weekly or exit average daily gain (ADG)
Feed delivered and feed disappearance by room or phase
Mortality: date, cause where known, weight if feasible
Removals and hospital transfers
Treatments: pig ID or group, sign, product, date (with veterinary authorization)
Days in nursery and average exit weight

Calculate feed conversion ratio (FCR) for nursery phases where possible. A useful FCR benchmark varies with diet composition, target weight, and genetic line; compare against your own rolling average and investigate batches that deviate significantly. USDA NRCS and extension resources provide swine enterprise benchmarks, but local conditions, genetics, and management systems make farm-specific trend analysis more actionable than comparisons to generic industry averages.

Common Mistakes

Placing pigs into a cold room. Pre-heat the room to target temperature before pigs arrive; cold floors absorb heat faster than lamps can supply it.
Ignoring drinker access on day 1. Dehydration at placement is a major and preventable driver of poor starts.
Switching feed phases abruptly. Gut microbial communities and enzyme profiles adjust gradually; a sudden diet change increases post-weaning scour risk.
Observing the room rather than individual pens. A pen with two sick pigs is invisible to a room-level walkthrough.
Continuous flow in a room designed for all-in all-out. Partial fills negate the pathogen-break benefit.
Treating without recording. Unrecorded treatments create withdrawal compliance risks, obscure health patterns, and compromise veterinary oversight.
Mixing significantly different-sized pigs. Poor-doers in a mixed-weight pen are more likely to fail without early identification.

Welfare, Biosecurity, and Regulatory Caveats

The post-weaning period carries heightened welfare risk: pigs are immunologically naïve, socially stressed, and adapting to a new diet. Welfare assurance programs typically require evidence of daily observation, appropriate stocking density, functioning water and feed equipment, and access to prompt veterinary care. Minimum weaning age is regulated in some jurisdictions (e.g., the EU requires a minimum of 28 days except under specific conditions); confirm the legal minimum for your location.

Biosecurity during nursery placement is also critical. Sourcing pigs from multiple farms increases pathogen diversity introduced into the nursery. Where possible, work with a defined pig source with a known health status. Vehicles delivering pigs should not enter the farm's clean zone; a dedicated loading area with a clean/dirty line protects the production site. Consult USDA APHIS swine biosecurity resources for guidance applicable to US operations.

Antimicrobials used in the nursery must comply with the Veterinary Feed Directive (US) or equivalent regulations. All in-feed or injectable treatments require veterinary oversight, a valid VCPR, and complete withdrawal records. Work with your veterinarian to establish a written health plan that specifies observation thresholds for treatment, authorized products, and record requirements.

When to Involve a Professional

Involve the herd veterinarian when diarrhea affects multiple pens concurrently, when mortality exceeds your established baseline, when neurologic signs or unusual deaths occur, when respiratory disease becomes widespread, or when treatments are not resolving problems within the expected timeframe. Submit diagnostic samples early in an outbreak rather than after extensive losses; the USDA APHIS National Veterinary Services Laboratories and state veterinary diagnostic labs can support pathogen identification.

A swine nutritionist should review the phase-feeding program, ingredient formulations, and feed delivery at least annually, and any time growth performance deviates significantly from expectation.

Frequently Asked Questions

What is the right temperature for a nursery room when pigs are first placed?

Newly weaned pigs typically require a floor-level air temperature of approximately 28,30 °C at placement. This target depends on pig size, floor type, group size, and whether supplemental heat (mats or lamps) is provided. Temperature should be confirmed at pig level, not ceiling height, and adjusted downward gradually,roughly 2 °C per week,as pigs grow and develop thermoregulatory capacity. Observed pig behavior (piling = too cold; spread along cool surfaces = too hot) is the primary feedback signal.

How long should nursery pigs be fed complex starter diets?

There is no universal answer. Phase-1 complex starters are typically fed for roughly the first 1,2 weeks after weaning, while phase-2 diets follow for another 2 weeks or so before transitioning to a grower diet. The appropriate timing depends on weaning age, placement weight, health status, and economics. A qualified swine nutritionist should set transition weights and timing for your system; early transitions to cheaper diets can cost more in reduced performance and health than they save in feed cost.

What causes post-weaning diarrhea, and how can it be prevented?

Post-weaning diarrhea has multiple contributing causes: bacterial pathogens (notably certain strains of Escherichia coli), viral agents, dietary changes, and the gut inflammation associated with the weaning transition itself. Prevention rests on a combination of all-in all-out management, thorough room cleaning and drying between groups, gradual feed introduction with highly digestible ingredients, stable social groupings, and appropriate temperature and ventilation. Diagnosis should involve laboratory investigation and veterinary guidance before selecting a management or treatment response.

What weight should nursery pigs reach before transferring to grow-finish?

Commercial operations commonly transfer at approximately 25,30 kg liveweight, though this varies by system design, season, grow-finish facility capacity, and genetics. The more important consideration is uniformity: a narrow weight range at transfer leads to a more even grow-finish group. Pigs significantly below average weight at nursery exit,often called poor-doers,may benefit from an extended nursery period in a dedicated pen rather than being mixed with larger animals at grow-finish entry.

Related Clinical & Scientific Guides

References and Further Reading

WOAH: Animal welfare and pig production systems (current chapter)
Iowa State University Extension: Post-weaning pig management
National Pork Board: Pork Quality Assurance Plus (PQA+)
USDA APHIS: Protect Our Pigs,biosecurity for producers
University of Minnesota Extension: Swine production resources
Penn State Extension: Swine nutrition and feeding management
National Pork Board: Common Swine Industry Audit
USDA APHIS: National Veterinary Services Laboratories,swine diagnostics

Related Farming Guides

Educational notice: This article is educational and is not a substitute for veterinary diagnosis, treatment, or prescription; nutritional advice from a qualified swine nutritionist; engineering design; or regulatory guidance. Feed and treatment programs in the nursery phase require veterinarian oversight and must comply with applicable regulations, including the Veterinary Feed Directive or local equivalent. Consult qualified professionals and your local regulatory authority for decisions affecting animal health, welfare, food safety, and the environment.