Nutrition profoundly affects sow welfare across all stages of production — gestation, lactation, and recovery. Managing sow nutrition for welfare requires balancing immediate nutritional needs with long-term body condition, reproduction, and longevity.
Gestating sows in conventional systems are typically fed 2-2.5 kg of feed daily — approximately 50% of their ad libitum intake. This chronic restriction prevents obesity during gestation but causes persistent hunger and feed-related frustration. Sows in restricted systems spend hours performing oral behaviours (bar-biting, rooting) indicative of unsatisfied feeding motivation.
Provision of high-fibre diets (beet pulp, straw, alfalfa) at greater volume reduces hunger without excess calorie provision — a welfare improvement over simple calorie restriction on concentrated diets. Foraging opportunities and ad libitum straw access address behavioural as well as nutritional needs.
Lactating sows have enormous nutritional demands — producing 8-12 litres of milk daily requires high feed intake. Insufficient energy intake during lactation causes excessive body condition loss (body condition score decline), delayed return to oestrus, and reduced subsequent litter size. Severe body condition loss impairs sow longevity — a welfare and productivity concern.
Welfare-positive management provides ad libitum water access (lactating sows drink 20-30 litres daily), high-quality feed, and multiple daily meals during lactation.
Body condition scoring (BCS) — assessing fat reserves on a 1-5 scale by visual assessment and palpation — is an essential welfare monitoring tool. Target BCS of 2.5-3.5 at farrowing, declining to 2.0-2.5 at weaning, then recovering before next farrowing represents an appropriate management target. Sows consistently in poor condition (BCS <2.0) or obese (>4.0) are experiencing welfare compromise from nutritional mismanagement.
Deficiencies in specific micronutrients cause specific welfare impacts. Iron deficiency anemia in sows increases fatigue and affects milk quality for piglets. Biotin deficiency impairs hoof integrity. Vitamin E and selenium deficiency cause muscle disease. A comprehensive welfare-focused nutritional program prevents these deficiencies through appropriate supplementation.
Electronic sow feeding (ESF) systems in group housing allow individual nutritional management of group-housed sows. Each sow receives her ration in a protected feeding station, reducing competition stress while allowing group social housing. ESF systems represent a welfare improvement over individual stalls by combining appropriate nutrition with social housing.