Growing Pig Welfare: From Weaning to Finishing

Welfare of Growing Pigs: Weaning to Slaughter

The growing pig period — from weaning at approximately 28 days to slaughter at 100–120kg liveweight — represents the longest phase of the commercial pig's life (approximately 20 weeks). During this time, pigs face multiple welfare challenges including weaning stress, social disruption, competition for resources, environmental stressors, and disease pressure. Understanding and addressing these challenges is central to both welfare improvement and production efficiency.

Post-Weaning Challenges

Weaning represents one of the most significant welfare insults in pig production — a simultaneous social, nutritional, and environmental disruption:

Separation from sow and littermates causes acute social stress
Transition from liquid to solid feed creates nutritional challenges (post-weaning diarrhoea risk)
Mixing with unfamiliar pigs from other litters triggers aggression
New environment (temperature, space, bedding) adds environmental challenge

Evidence-based mitigation: Weaning at older age (28+ days), providing creep feed before weaning, and minimising litter mixing at weaning significantly reduce post-weaning stress.

Space Allowance and Welfare

Minimum legal space allowances (EU and UK Welfare of Farmed Animals Regulations) specify:

Weaned pigs <10kg: 0.15 m²/pig
10–20kg: 0.20 m²/pig
20–30kg: 0.30 m²/pig
30–50kg: 0.40 m²/pig
50–85kg: 0.55 m²/pig
85–110kg: 0.65 m²/pig
>110kg: 1.00 m²/pig

Research consistently shows that higher space allowances above legal minimums reduce aggression, improve lying behaviour, and support better immune function. The Brambell-influenced Five Domains model highlights freedom of movement as a positive welfare requirement, not merely a minimum.

Enrichment Requirements

UK law requires that pigs have permanent access to enrichment materials that are manipulable, chewable, and interest-sustaining. Best practice enrichment for growing pigs:

Rooting materials: Deep straw, peat, compost (most effective but highest cost)
Manipulable objects: Hanging chains, hanging balls, wood blocks, hessian
Foraging opportunity: Scatter feeding, novel food items
Cognitive challenge: Puzzle feeders, rotating novel items

Enrichment provision is the single most effective intervention for preventing tail biting — the most costly welfare problem in commercial pig production.

Disease and Welfare

Key diseases affecting welfare in growing pigs:

Post-weaning diarrhoea (PWD): E. coli-mediated; causes dehydration, pain, and significant mortality if untreated
PRRS (Porcine Reproductive and Respiratory Syndrome): Respiratory and immune suppression across all ages
Swine influenza: Causes pyrexia, respiratory signs, and significant welfare impact during outbreaks
Ileitis (Lawsonia intracellularis): Causes chronic or acute diarrhoea and weight loss in growing pigs

Positive Welfare Indicators

Welfare assessment in growing pigs should go beyond absence of illness to include positive states:

Play behaviour (running, jumping, social play) — indicator of positive affective state
Exploratory behaviour (rooting, nosing enrichment materials)
Social affiliative behaviour (lying in contact, gentle nuzzling)
Good body condition and coat quality
Responsive, alert demeanour when observers enter

Practical Management Recommendations

Wean at minimum 28 days; avoid mixing litters at weaning where possible
Maintain temperature at 28-30°C for newly weaned pigs, reducing to 18-20°C at finishing
Provide minimum 2 enrichment items per group, rotating weekly to maintain novelty
Inspect pigs daily — remove any bitten or injured animals immediately
Ensure feeder space of 7cm/pig minimum (wet-dry feeders preferred)
Monitor and record mortality, treatments, and tail-biting incidents as welfare KPIs