Condicions alternatives d'allotjament per a la millora del benestar i el rendiment de les truges i els garrins

Resumen

Conventional farrowing crate systems were designed to maximize production but did not consider the pigs’ biological needs, and therefore, compromise the welfare of sows and piglets. On one hand, farrowing crates do not allow sows to build a nest prior to farrowing, and they restrict the body movements and the interactions with their piglets during lactation. On the other hand, piglets are raised in a barren environment without sufficient sensory and social stimulations, which limits the development of their behavioral repertoire, including exploration, play and a variety of social skills, and that of their stress regulation system. The aim of this thesis was to study the effect of an improved housing environment during lactation on the welfare and performance of sows and piglets in intensive production systems. Two trials were conducted, each on a different commercial farm: Trial 1 focused on the implications of an improved environment during lactation from birth to slaughter, whereas Trial 2 focused on the behavior and welfare assessment of sows and piglets housed in either farrowing pens with temporary crating system or conventional crates until shortly after weaning. A similar methodology was used in both trials: direct observation to study behavioral differences, skin lesion scoring to study the aggression level, salivary stress biomarkers to monitor the stress response, and weight gain to study performance. In Trial 1, two treatment groups were differentiated during lactation: CON (control) and ENR (enriched). CON piglets were raised in conventional farrowing pens where sows were crated. ENR piglets were raised in the same farrowing pens but six enrichment objects for piglets were installed in each pen from birth, and the barriers between two ENR adjacent pens were removed at 14 days after farrowing to allow piglet socialization. Pigs in two treatment groups were raised in the same way after weaning until being slaughtered. There were both short- and long-term benefits of raising piglets in an improved environment. The facilitation of social and play behaviors during lactation assisted ENR piglets to adapt better to weaning, by displaying less aggression, and showing a lower stress response after weaning. Social skills obtained at the early age persisted until pigs were slaughtered, which was evidenced by a higher short-term weight gain after two regrouping events, and fewer skin lesions on carcasses after pre-slaughter mixing. In Trial 2, three farrowing systems were tested: FC (conventional crate), and two commercial farrowing pens with temporary crating system (TC), SWAP (Sow Welfare And Piglet protection) and JLF15. FC sows were crated from entry to weaning, while SWAP and JLF15 sows were crated for 5 to 6 days during the peripartum. TC sows interacted with piglets more frequently than FC sows, whereas FC piglets interacted with littermates more frequently than TC piglets. The day of crate opening facilitated exploration in TC sows, compared to FC sows. There was a higher crushing rate in TC. SWAP piglets adapted better to weaning stress as they showed a lower stress response. The results of this thesis suggest that creating an improved housing environment during lactation (i.e. environmental enrichment and early socialization, or temporary crating environment) facilitates play in piglets as well as exploration and mother-young interactions in sows and piglets. An improved housing environment during lactation broadens the behavioral repertoire of sows and piglets, which can contribute to pigs’ resilience when facing weaning or regrouping challenges later in their lives. Housing conditions that consider the pigs’ biological needs, improve some welfare and performance traits of sows and piglets, which indicates feasible improvement strategies in intensive pig production.