Effetto di differenti arricchimenti ambientali sul benessere di suini nella fase di ingrasso

Introduction - The intention of the new European legislation on rooting materials for pigs is to improve the welfare of pigs, supporting their need to express exploratory behaviours (i.e. rooting, sniffing, and chewing), reducing the risk of the pigs performing abnormal behavioural patterns that may be harmful to their pen mates. Aim - The aim of this study is to gather information about the effect of different types of environmental enrichments on fattening pigs behaviour. Materials and methods - The study was conducted in a commercial farm in the Province of Mantua. From 560 pigs, 6 experimental groups were created: 5 enriched groups (spinning top, cylinder, brick, ball, stub), 1 control group (with no enrichment). Behavioural observations were performed using instantaneous and scan sampling method (60 min/10 min scan; twice/day; 3 times/week; 3 months). The number of body lesions was collected and divided into 4 classes (from abscence of lesions to severe presence of lesions). Animals were observed at the beginning of the fattening period (enrichments introduction), after a month, and at the end of the fattening period, before slaughtering. Behavioural data were analysed by GLM repeated measures to evaluate the effect of enrichment, time, and their interactions; data related to the number of pigs with lesions (expressed as percentage of event occurred) were analysed by a non-parametric analysis of variance (Kruskall-Wallis test). Results and discussion - The results show both different interest over time towards the enrichments and different use of them: data suggest that pigs significantly prefer the spinning top and the cylinder (p<0.001), probably due to the material of the object (metal) that can avoid the faecal soiling, although these enrichments only satisfy an exploratory behaviour, but not a manipulative behaviour. The use of spinning top and cylinder does not decrease during the whole observation period, compared to the other enrichments (p<0.001). As expected, the control group presents lower frequencies for all the expressed behaviours, except for inactive behaviours, probably due to a “rebound” effect. The groups enriched with spinning top and cylinder present the lowest percentages of pigs with lesions, whereas the control group and also the stub group present a severe percentages of pigs with lesions. For control group, the result is quite expected, while for stub group, it may indicate that inadequate enrichments have no effect on pigs. Conclusions - Although pigs prefer objects with manipulative characteristics (i.e. easy to root, chewable, changeable, and destructible), such as the brick and the stub, we can conclude that if the enrichment object is placed on the ground, the pigs will focus the attention to objects with particular materials (such as metal) that can reduce the faecal soiling. This is probably the reason why they significantly chose the spinning top and the cylinder. Choosing the right environmental enrichment can improve the welfare of pigs housed in barren pen and reduce undesirable behaviours (e.g. aggressive behaviour towards the pen mates).

Negli allevamenti intensivi suinicoli, l’impossibilità di soddisfare i comportamenti esplorativi propri della specie è un’importante problematica di benessere animale sulla quale vertono le nuove normative. Il presente studio ha lo scopo di valutare l’effetto di diverse tipologie di arricchimento sul comportamento di suini nella fase d’ingrasso. La prova sperimentale, condotta presso un allevamento suinicolo in provincia di Mantova, ha coinvolto 560 soggetti ibridi: cinque gruppi sperimentali (n=80) con arricchimento (trottola, cilindro, mattone, palla, tronchetto) e un gruppo di controllo (n=160; nessun arricchimento). I rilievi comportamentali sono stati realizzati tre giorni a settimana in tre periodi (inizio ciclo, dopo un mese e prima della macellazione), mediante instantaneous and scan sampling method (due fasce giornaliere di 60 minuti ciascuna, intervalli campione di 10 minuti). Inoltre, sono state contate e classificate le lesioni cutanee. I risultati evidenziano sia un interesse differente nel tempo (p<0,001) verso gli arricchimenti sia un diverso utilizzo (p<0,001): i suini prediligono trottola e cilindro, senza diminuirne l’utilizzo. Pur soddisfacendo un comportamento di tipo esplorativo non manipolativo, è probabile che la natura metallica di tali oggetti sia stata preferita dai suini per la minor contaminazione fecale, riscontrata invece negli altri arricchimenti. Nei box con gli arricchimenti più utilizzati, i suini hanno riportato un numero inferiore, seppur non significativamente differente, di lesioni, avendo probabilmente rivolto la loro attenzione più all’arricchimento che ai conspecifici. In conclusione, si sottolinea l’importanza di scegliere con attenzione l’arricchimento più idoneo per ottenere un effetto positivo sul comportamento.