A practical guide to managing pigs through the phases

Managing pigs from weaning through to market weight is a meticulous process that combines science, management, and attention to detail.

Each production stage carries unique challenges, from nutrition and housing to herd health and environmental management. Optimising these aspects is critical, not only for achieving desirable growth rates and carcass quality, but also for ensuring economic viability and animal welfare.

Dr Dorothea Mostert, a veterinarian at CSVet, provides extensive practical guidance for farmers navigating the complex journey from weaning to finishing, offering insights into how to measure, monitor, and manage pigs for optimal results.

Dividing production phases: Weaner and grower-finisher

“By convention, we divide the growing pig’s life into two main sections. From weaning until transfer, pigs are classified as weaners. After transfer, they move into the grower and finisher phase, where they remain until market weight,” says Mostert.

This division is crucial, because pigs’ nutritional needs, growth potential, and housing requirements differ markedly between these phases. Understanding these differences allows farmers to set realistic targets and intervene proactively when performance deviates from expectations.

Weaner phase

Weaning represents a significant transition for piglets, moving from a milk-based diet to solid feed. Their digestive systems are still developing, and their environmental requirements are very specific.

• Target weights: piglets weaned at 21 days should ideally weigh between 6,8kg and 7kg, while those weaned at 28 days should approach 8kg. Mostert recommends weighing entire litters rather than individuals to monitor overall litter quality;
• Average daily gain (ADG): weaners typically achieve an ADG of around 450g/day, though this can vary depending on breed, nutrition, and housing;
• Environmental needs: newly weaned pigs require a warm environment, ideally 28°C to 29°C, with no draughts, adequate fresh air, and moderate humidity. Proper environmental control reduces stress and supports feed intake, which is critical for early growth and health;
• Nutrition: highly digestible feeds are essential. Ingredients such as milk powders and carefully processed maize can enhance growth and feed conversion efficiency. “The investment in quality feed during the weaner phase pays off later in reduced mortality and better growth,” notes Mostert.

Grower-finisher phase

After transfer at roughly 10 weeks or 32kg, pigs enter the grower-finisher phase, where growth accelerates and environmental needs shift.

• Target weights: market weight targets vary by market type, but most farms aim for 112kg live weight for standard carcasses, with premium operations reaching 120kg to 122kg;
• ADG and FCR: modern genetics allow pigs to gain over 950g/day, with top farms achieving 1kg to 1,1kg. Typical feed conversion ratios (FCRs) range from 2,1kg to 2,7kg of feed per kilogram of weight gain. Monitoring ADG and FCR allows farmers to detect inefficiencies early;
• Environmental considerations: As pigs grow, their metabolic heat production increases. This reduces their need for artificial heating, but introduces the challenge of maintaining comfort during hot weather. Modern pig housing often includes automated ventilation and cooling systems, while curtain-sided houses require manual monitoring.

“The better we can manage the environment to keep pigs comfortable, the better results we’ll see,” says Mostert.

Nutrition management:the cornerstone of efficiency

Feed represents the single largest input cost on a pig farm, typically accounting for up to 70% of total production expenses. Mostert mentions that optimising nutrition is both an art and a science.

Weaner diets

• Highly digestible feeds are essential in the early weeks post-weaning;
• Ingredients such as milk powders, cooked maize, and balanced amino acids support early gut development;
• Feed consistency and particle size matter. Variation in ingredient quality can reduce feed intake and growth.
• Grower diets
• As pigs’ digestive systems mature, formulations can shift to cost-effective proteins and energy sources;
• Adjustments in amino acid profiles, fibre, and energy content allow pigs to maintain growth without excessive fat deposition;
• Monitoring intake ensures that pigs are consuming the correct quantities for efficient growth.

Finisher diets

• High energy and balanced protein-to-energy ratios help pigs achieve target carcass weights; Feed can be adjusted to influence back fat, ensuring carcasses meet market grading standards. Mostert advises ongoing consultation with a nutritionist to tailor diets to local conditions and seasonal requirements.

“Nutrition on paper is only part of the equation. Consistency, particle size, and ingredient quality directly affect the feed conversion and the bottom line,” she says.

Environmental management

Pigs are highly sensitive to their environment. Effective control of temperature, humidity, ventilation, and air quality is critical to both growth and welfare.

Temperature control

• Weaners: they prefer 28°C to 29°C upon placement, with the comfortable temperature requirement gradually lowering towards 21°C at transfer. A draught-free environment ensures optimal feed intake and minimises stress;
• Growers and finishers: increased metabolic heat reduces the need for artificial heating. However, high temperatures can suppress appetite and growth;
• Housing should allow temperature adjustments to align with seasonal changes.
• Ventilation
• Adequate airflow reduces ammonia accumulation and supports respiratory health;
  Automated systems with sensors allow for continuous monitoring and adjustment;
• Manual systems require daily checks with thermometers and careful observation of pig behaviour.

Humidity: excess humidity can exacerbate heat stress, disease spread and also assist in reducing feed efficiency;

• Proper drainage, bedding, and ventilation help a great deal in maintaining moderate levels. Even with sophisticated technology, human observation is irreplaceable.

The role of stockmen

“Stockmen must monitor behaviour to detect heat stress, cold stress, or discomfort,” says Mostert.
Pigs’ body language often provides the earliest warning of environmental problems.

Stocking density and resource management

• Maximising building use: overcrowded enclosures lead to pigs experiencing stress, slower growth, and increased disease risk;
• Space allocation: calculate based on expected market weight, not just early growth stages.
• Feeders and drinkers: ensure enough for all pigs. Limited access restricts growth regardless of floor space.
• Holistic resource management: floor space, feed, water, and ventilation must be coordinated for optimal growth.

Monitoring feed efficiency

Feed efficiency is measured not just by FCR but also by cost per kilogram gain, which combines feed quality, intake, and growth performance.

• Cost-effective feeding: a cheaper feed that requires higher intake may cost more per kilogram gain than a higher-quality feed eaten in smaller amounts;
• Average daily feed intake (ADFI): monitoring intake helps detect stress, disease, or equipment problems;
• Days to market: provides insights into batch turnover and farm efficiency.

Carcass quality and full-value pigs

Monitoring carcass outcomes is critical for profitability.

• Weight consistency: track average carcass weight and variation within the batch;
• Grading: use classification systems like PORCUS to assess leanness. Most pigs should fall into lean and very lean categories;
• Full-value pigs: measure how many reach ideal market weight without trimmings or discounts. This key performance indicator reflects production efficiency and potential revenue loss.

Mortality management

Minimising mortality improves both welfare and profitability.

• Weaner mortality: target around 1%.
• Grower-finisher mortality: aim for less than 2,5%.
• Key strategies: start with healthy piglets, maintain optimal environment, provide appropriate space, and implement robust health programmes.
• Seasonal risks: heat stress can increase mortality in summer, while cold stress can drive overconsumption of feed in winter;

Seasonal adjustments

Pigs respond strongly to seasonal changes, affecting feed intake, growth, and welfare.

• Summer: high temperatures reduce appetite and increase water waste. Cooling systems and adequate ventilation are essential;
• Winter: cold temperatures increase feed intake for thermoregulation. Higher fibre rations can help pigs feel full while generating heat during digestion.

Technology for monitoring and efficiency

Modern pig farming increasingly incorporates technology to measure, analyse, and manage performance.

• Load cells under silos: track feed consumption in real-time;
• Water flow meters: detect unusual patterns indicating stress or health issues;
• Environmental dashboards: monitor temperature, humidity, and ventilation; alert staff to failures;
• Return on investment: farmers must assess whether the cost of technology translates into measurable production gains.

Tracking production costs

Mostert mentions tracking input costs and outputs per batch.

• Inputs: feed, medication, housing, management, labour;
• Outputs: carcass revenue at slaughter;
• Batch-specific mortality and losses: allocate every death, feed loss, or accident to the correct group;
• Phase breakdown: recording weights at weaning, transfer, and market provides detailed insight into growth and efficiency.

Practical Checklists for Farmers

To implement these principles effectively, farmers can adopt daily, weekly, and monthly routines:

Daily

• Observe pigs for heat or cold stress;
• Check for signs of disease or stress in pens;
• Check feeders and waterers;
• Monitor environmental parameters (temperature, humidity, airflow);
• Record feed and water intake per batch.

Weekly

• Monitor mortality and health interventions;
• Evaluate FCR and adjust feed rations if necessary;
• Plan feed orders to ensure pigs are fed ad lib.

Monthly

• Compare batch performance to historical averages;
• Review feed efficiency and costs per kilogram gain;
• Analyse carcass data and grading results;
• Adjust housing or nutrition strategies for upcoming batches or seasonal changes.

Troubleshooting common issues

Even well-managed farms encounter challenges. Mostert suggests practical solutions:

• Uneven growth: check feed access, environmental comfort, and social dynamics in pens;
• High mortality: investigate health, vaccination compliance, temperature, and water quality;
• Feed wastage: adjust feeder settings, improve delivery schedules, and maintain equipment;
• Seasonal performance dips: use environmental adjustments and diet modifications to compensate for temperature stress.

Holistic management for profitability

Managing pigs from weaning to finishing is an intricate balancing act. Success requires attention to nutrition, housing, environmental controls, health, and economic tracking.
Small, well-informed decisions compound into significant improvements in growth, welfare, and profitability.

“Producers who monitor closely, adapt strategies continuously, and apply a holistic approach, achieve healthier pigs, efficient growth, and profitable operations,” says Mostert.

By combining scientific principles, technological tools, and practical experience, modern pig producers can optimise performance throughout the production cycle and turn weaners into high-quality, market-ready pigs while ensuring economic sustainability.