Hypothetical Welfare Assessments for the Sow and Her Litter
The assessment of welfare within farrowing systems presents a unique challenge for pork producers, veterinarians, and animal scientists. Welfare assessment within all other phases of swine production involves pigs at a single stage of their productive life. Within the farrowing environment, the sow and her piglets are at two very different stages of their life, and have different requirements in regards to their thermal, social, and physical environments . A system that may be ideal for the welfare needs and requirements of the sow may be far from optimal for her piglets, and vice versa. In order for objective and science-based assessments to be conducted on swine farms, we must have an appreciation of the sows and her piglets welfare during farrowing and lactation.
Overall Assessment of Welfare in Different Farrowing/Lactation Systems
The information presented is based on hypothetical systems used in commercial swine practice. The comparison tables are divided into six distinct parts that have already been identified that sows pass through when preparing for birth and subsequent lactation, these are: (i) isolation and nest site seeking, (ii) nest building, (iii) farrowing, (iv) nest occupation, (v) social integration, and (vi) weaning . However, note some caveats; these are generalizations to illustrate concepts based on scientific literature. On any given farm, welfare within a farrowing system will be influenced by many things including system design, herd health, genetics, feeding system, gestation system, and the skill of the caretakers. Extrapolation of the discussion below to a specific system not described would not be applicable and is therefore ill-advised. The scoring system is purely qualitative rather than quantitative and is not weighted. We also make the assumption that the sows exhibit good maternal behavior, so that the limitations of the system, rather than the sow, are highlighted.
Sow Versus Piglet
The most important aspects that this exercise highlights are perhaps the fact that conventional stalls rank poorly for both sow and piglet welfare, based on the review of the scientific literature, but that modifications including bedding, mixing of litters pre-weaning, increasing weaning age slightly and offering creep feed can certainly improve welfare within the system. For the sows, group-housing appears to offer welfare advantages, but these systems certainly increase the management skills needed by the stockperson and without these, welfare scoring could be considerably lower. Also, and the real crux of the welfare assessment problem, where the sow is loose-housed, piglet welfare during the nest occupation phase tends to be disadvantaged, with the disadvantage being an increase in early pre-weaning mortality. This remains the key problem with alternative farrowing systems as it represents a major economic loss to the producer as well as a welfare issue.
The assessment of welfare within farrowing systems remains a difficult area of research due to the conflicting needs of the sow and her litter. Conventional farrowing stalls can safeguard piglet welfare during the nest occupation phase of farrowing, especially limiting early pre-weaning mortality, which is an extremely important factor for the welfare of the individual piglet and also for the profitability of the commercial producer. However, conventional stalls also have some disadvantages with respect to sow welfare during other stages of lactation. Many alternative systems exist, albeit at an economic cost to the producer, and most confer welfare benefits during some of the farrowing stages. For increased piglet mortality not to be a problem which currently it is, there needs to be a greater reliance on the selection of our gilts and sows for positive maternal traits (i.e. rooting, pawing and being responsiveness to their piglets) and a greater reliance on caretaker skills to manage the farrowing and lactating systems optimally.
Table 1. Hypothetical systems descriptions and scoring rationale (authors have picked the inputs of the system.)
|Name||Design features||Bedding||Social||Sow to litter||Creep feed||Length||Weaning|
|Standard farrowing stall||Conventional tubular metal farrowing stall on fully-slatted floor . Sow cannot isolate or seek nest site. Inability to nest-build can result in disturbed farrowing, placing newborn piglets at risk of crushing or stillbirth.||No bedding but heated creep area for piglets.||Litters kept intact with sow – no mixing||Help newborn piglets locate udder more easily.||Often no||2 to 3 weeks||Piglets moved and mixed with unfamiliar piglets.|
|Turn around stall||Conventional tubular metal farrowing stall on solid floor . Sow cannot isolate but does have limited nest building capabilities.||Long-stem straw and a heated creep area for piglets.||Litters are kept intact for 10 days and then partitions between 3 pens are removed allowing litters only to mix.||As for standard farrowing stalls||After 2 weeks||4 weeks||Piglets are moved at weaning but are not mixed with any unfamiliar piglets.|
|Hinged stall||Hinged tubular metal crates on solid floor .||As for modified stalls||Sow kept in closed stall until litter is 7 days of age. Stall is opened. No mixing.||As for standard farrowing stalls||No||3 to 4 weeks||Piglets moved and mixed with unfamiliar piglets.|
|Open pens||Solid floor Partial/slatted floor||Long stem straw bedded floor with/without protection rails . Creep area.||No litter mixing||Risk of crushing is higher. Sow has more control over nursing and movement.||No||3 to 4 weeks||Piglets moved and mixed with unfamiliar piglets.|
|Outdoor hut||Insulated steel English style arks  ‘A’ frame, and other plastic and plywood models in paddock for single sow, ringed by an electric fence. Piglets are contained within the ark for 7 to 10 days by a fender and then released into the paddock.||Some grass cover and bedding inside ark||Sow kept on own.||As for open pens||No||3 weeks + (depends on the marketing scheme)||Piglets have been able to mix.|
|Swedish style multi-suckling pens|
|Ljungstrom||Sows housed individually solid-floored pens with piglet protection rail around perimeter . Heated creep.||Straw||Sow and litter kept intact for 14 days and then moved together to a deep-bedded multi-suckling pen with 9 other sows and litters.||As open pens||After 2 weeks||6 weeks|
|Thorstensson||Eight sows group-housed in a large, deep straw-bedded pen with 8 individual temporary pens down one side .||Piglets kept in nest for 10 days and then mixed||As for outdoor huts||After 3 weeks||6 weeks|
|Grouped Arks||Insulated farrowing arks ( in a group paddock for 6 sows ringed by an electric fence. Piglets contained in nest for 10 days and then mixed.||As for single arks||Sow is grouped before and during a 3 to 4 week lactation period.||As for single ark||No||3 weeks + (depends on the marketing scheme)|
Table 2. Qualitative sow and litter welfare scores for each hypothetical system over six separate phases of farrowing .
|System||Isolation & Nest-site seeking||Nest-building||Farrowing|
|Sow welfare||Litter welfare||Sow welfare||Litter welfare||Sow welfare||Litter welfare|
|1. Standard farrowing stall||xx||xx||x||–|
|2. Turn around stall||xx||–||–||–|
|3. Hinged stall||x||–||–||–|
|4. Open pens||–||✓||✓||✓|
|5. Outdoor huts||✓||✓✓||✓||✓|
|6. Swedish style multi-suckling pens: Ljungstrom system||–||✓||✓||✓|
|7. Swedish style multi-suckling pens: Thorstensson system||✓||✓✓||✓||✓|
|8. Grouped outdoor huts||✓||✓✓||✓||✓|
Table 3. Qualitative sow and litter welfare scores for each hypothetical system over six separate phases of farrowing .
|System||Nest occupation||Social integration||Weaning|
|Sow welfare||Litter welfare||Sow welfare||Litter welfare||Sow welfare||Litter welfare|
|1. Standard farrowing stall||xx||✓✓||xx||xx||xx||xx|
|2. Turn around stall||xx||✓✓||xx||✓||x||✓|
|3. Hinged stall||x||✓✓||x||xx||xx||x|
|4. Open pens||–||xx||x||xx||xx||x|
|5. Outdoor huts||✓||xx||x||✓✓||✓||✓|
|6. Swedish style multi-suckling pens: Ljungstrom system||✓||xx||✓||✓||✓||✓✓|
|7. Swedish style multi-suckling pens: Thorstensson system||✓✓||xx||✓✓||✓✓||✓||✓✓|
|8. Grouped outdoor huts||✓✓||xx||✓✓||✓✓||✓||✓|
✓✓ large positive effect on welfare
✓ positive effect on welfare
– neutral effect on welfare
x negative effect on welfare
xx large negative effect on welfare
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