Effect of environmental enrichment and group size on the water use and waste in grower-finisher pigs

Shilpi Misra,Eddie A M Bokkers,Keelin O’Driscoll,Amy J Quinn,John Upton

doi:10.1038/s41598-021-95880-0

Abstract

The grower-finisher stage accounts for 64% of the total on-farm herd water use. Part of this is consumed by the pigs, but a part is also wasted. Drinking water usage and wastage is affected by different factors. We investigated how different group sizes and different levels of enrichment affect water usage (ingested plus wasted), water wastage, behavior and performance in grower-finisher pigs. Pigs (n = 672), 11 weeks of age (77 ± 2 days) were used for the experiment. The effect of group size: SMALL (12 pigs), MEDIUM (24 pigs), and LARGE (48 pigs) was assessed across two levels of enrichment (LOW—wooden post, hanging rubber toy, HIGH—Same as LOW + fresh grass). There was no effect of group size on water use or wastage. Pigs with HIGH enrichment (10.4 ± 0.4 L/pig/day) used less water than LOW enrichment (11.0 ± 0.4 L/pig/day; p < 0.001). The water wastage/drinker/hour was lower in pens with HIGH enrichment than LOW (p = 0.003). The drinking bout number (p = 0.037) and total occupancy/hour (p = 0.048) was also higher for pens with LOW than HIGH enrichment. Aggressive and harmful behaviour were performed less in LARGE groups and pens with HIGH enrichment. Thus, HIGH enrichment allowance reduced water usage and wastage so may have benefits for the environment, as well as animal welfare.

Highlights

The grower-finisher stage accounts for 64% of the total on-farm herd water use
A tendency (p = 0.083) towards lower water use was found in MEDIUM pens with HIGH enrichment compared to MEDIUM pens with LOW enrichment
Our hypothesis was confirmed regarding the provision of enrichment; pens with HIGH enrichment used less water per pig than pens with LOW enrichment and this was likely due to less water being wasted in this treatment

Summary

Introduction

The grower-finisher stage accounts for 64% of the total on-farm herd water use. Part of this is consumed by the pigs, but a part is wasted. We investigated how different group sizes and different levels of enrichment affect water usage (ingested plus wasted), water wastage, behavior and performance in grower-finisher pigs. When stocking density is kept constant, pigs in larger groups have more shared space per pig, which could provide a more complex and engaging environment for them The impact of this on drinking behavior has not been fully explored, but it could be that more shared space leads to less engagement with the drinker resulting in less wastage, as pigs have a greater area for exploration. These results indicate that pigs do not seem to use drinkers purely for d rinking[8,13]. With regard to the type of material to provide in a rack, either fresh grass, or grass silage seems favored by pigs over straw; silage keeps pigs occupied for longer[17], and more grams of fresh grass are used per day than straw[15]

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