Substrate-based enrichment recommended for sows during pregnancy

  • Subject
    Short review on the current knowledge on behavioural needs of sows in terms of feeding and exploration
  • Target audience
    Competent Authorities, inspectors and welfare policy workers of the EU Member States
More info and sources
In a short review, EURCAW-Pigs provides background on the behavioural needs of sows in terms of feeding and exploring. Furthermore, different methods to offer enrichment material to sows during pregnancy are highlighted.

Lack of satiety

In commercial housing, pregnant sows are fed restricted with one or two meals per day to prevent excessive weight gain in pregnancy, which may cause problems around farrowing. However, restrictively fed sows are often not satiated and still show a high feeding motivation, which is a sign of hunger and may provoke stereotypies. Thus, pregnant sows and gilts must be given a sufficient quantity of bulky or high-fibre food in addition to a high-energy food in order to satisfy their hunger and given their need to chew [Council Directive 2008/120/EC, Article 3(7)].

Foraging motivation

Feed intake is accomplished with foraging performed by sows for 40-70 % of the day in semi-natural environments. Pigs perform exploratory behaviour also at objects of the housing environment (e.g. chains) even when a biological stimulus (e.g. organic substrate or food) is absent. This indicates that exploratory behaviour is also intrinsically motivated. According to EU legislation, sows must have permanent access “to a sufficient quantity of material to enable proper investigation and manipulation activities, such as straw, hay, wood, sawdust, mushroom compost, peat or a mixture of such, which does not compromise the health of the animals” [Article 3(5) and Annex I, Chapter I, Point 4].

Substrate-based enrichment recommended

Suitable enrichment material for sows should address the lack of satiety and the resulting foraging motivation. Scientifically knowledge on effective enrichment material for pregnant sows is scarce. However, enrichment material can either be object or substrate-based. In any case, sufficient enrichment material should be edible, chewable, investigable and manipulable.

For feed-restricted sows, substrate-based enrichment (in the form of roughages) is recommended, since it not only provides exploration opportunities but also contributes to satiety and reduced prevalence of stomach ulcers. High amounts of roughages are best provided in housing systems with solid floors. For slatted floor systems, further investigations are needed to develop object-based enrichment materials that include characteristics such as the possibility to root.

Introphoto: Hay in a rack (©Antje Schubbert, FLI)