Pasture consumption and grazing behaviour of European wild boar (Sus scrofa L.) under continuous and rotational grazing systems

Abstract

The majority of the European wild boar (Sus scrofa L.) that are farmed for their meat are produced using semi-extensive systems with access to pasture for grazing. Given that the pasture is an economic resource compared with supplemental diets, there is interest in determining strategies to increase pasture consumption. The objectives of this study were to assess the effect of the grazing system (continuous grazing vs. rotational grazing) on pasture consumption and grazing behaviour of European wild boar under semi-extensive production system conditions. Sixteen purebred nose-ringed European wild boar (initial average bodyweight of 18.3±0.45kg) were grouped into eight pairs. The pairs were assigned to eight paddocks of 35m2 with a Trifolium repens and Lolium perenne pasture, during summer. Animals grazed from 0830h to 1630h after which each pair entered a feeding station and had free access to a supplemental feed. Supplemental feed consumption was measured. In the “continuous grazing” treatment the animals entered the same pasture area (35m2) daily for five days. In the “rotational grazing” treatment the animals entered a new strip consisting of one-fifth of the surface of the continuous grazing area (7m2) daily, for five days (first grazing period). After these five days of grazing in the experimental area, the animals were moved to other areas of the paddock in which they grazed for 13 days. The animals then returned to the experimental area for another five days (second grazing period), with a change-over of treatments (cross-over design). The animals were individually weighed on the first and final day of every grazing period. Pre- and post-grazing pasture samples were taken to assess pasture consumption, botanical composition and nutritional composition. The behaviour of the animals during the grazing periods was evaluated during each evaluation day. Every 5min the activity of each animal was recorded by an observer as “grazing”, “lying down”, “walking”, “taking a bath”, “drinking water”, “playing” or “other activities”. The average pasture consumption was 242±18gDManimal−1d−1 with no statistical difference between treatments. The animals spent 42.4% of their time “grazing”, being more active the first 3h (62% of their time grazing), and 45.4% “lying down” (especially from 1130h to 1530h), with no significant differences between treatments or periods. Pasture consumption and grazing behaviour of European wild boar does not differ between continuous and rotational grazing systems over a five-day period.