Grisars omedelbara beteende vid doftberikning

It is common knowledge that pigs are used to search for truffles and that their sense of smell is well developed. Still, there is not much research about pigs’ sense of smell and therefore the aim of this study is to describe which behaviours the pigs perform immediately when exposed to scent enrichment. This study was part of a larger research project about pig olfaction and scent enrichment for pigs. According to Swedish legislation, pigs must have enrichment, to ensure that they have an opportunity to perform their natural behaviours, and thereby reduce problematic behaviours such as tail biting. Before the test started, all pigs were habituated to the experimental pens and equipment. The test included twelve odours (aniseed, blood orange, vanilla, apple, cinnamon bark, musk, pine, jasmine, ginger, thyme, lavender, and cedar wood) and one control (distilled water). Each odour was attached to the test box and was available 3*1 minute, then removed for two minutes. Each test day three scents were tested three times each (total of nine presentations). The whole operation was video recorded, and the immediate behavioural reaction of the pigs was observed. One part of the study was to observe pigs’ behaviour during the first ten seconds. A reaction scale (0-5, where 0 is no reaction and 5 is the strongest reaction) was developed to study the pig’s immediate reaction towards the odours when detecting it for the first time. The average reaction score for the pigs when presented with the odour was 1.10. Some odours were more popular with the pigs, e.g., aniseed, jasmine, and ginger were sniffed more than all other odours. One of the most frequently observed behaviours was sniffing. In total, sniffing the odour was observed in 36% of the odour presentations. Although tail flicking has only previously been described in relation to discomfort, tail flicking was observed as an immediate reaction to blood orange, cinnamon bark and thyme and was not followed by any backing or fleeing from the odour. This may indicate that tail flicking was an autonomous reaction when the olfactory nerve was stimulated. In conclusion sniffing was the most frequently observed behaviour. One behaviour which may be associated with positive stimulus is biting in the hole, where the odours were presented, meanwhile headshaking can be associated with negative stimulus. The results in this study provide information about pigs’ behaviour related to odour and how scent enrichment can be implemented in the pig industry. These findings will contribute to increased knowledge about pigs with potential to improve their welfare. Further research is required before more conclusions can be drawn regarding pigs’ behaviour when exposed to odours

Odor exploration behavior of the domestic pig (Sus scrofa) as indicator of enriching properties of odors

Introduction and aim: Although the sense of smell in pigs is widely recognized as being highly developed, surprisingly little is known about their sensory ability. This study aimed to (a) identify which non-social odors pigs were able to detect and distinguish between, (b) investigate the types of behavior expressed when exploring odors and, (c) compare pigs’ responses to the different odors to evaluate their interest in the odors.Methods: Growing pigs (N = 192) of crossbred commercial breeds were enrolled in the experiment (32–110 days of age, weighing 64.9 ± 10.1kg). Littermate pairs of opposite sex were tested in test pens with two odor insertion points in the pen wall, 55 cm apart. All pigs were habituated to the test pens and experimenters. Twelve odors were tested (eight essential oils and four synthetic perfumes) in groups of three odors, with each pig pair tested once with one set of three odors (all possible orders of the three odors were tested on 24 pairs in total), always against a non-odor control (demineralized water). In a test, each of the three odors were presented during three trials in a row (a total of 9 trials per test; trial duration: 1 min; inter-trial breaks: 2 min; total test duration: 25 min). Response variables included: duration of sniffing, feeding-related behavior (licking, biting and rooting), agonistic behavior (biting, displacement and pushing) and no approach of the odor or control, recorded throughout each 1-min odor presentation.Results: All pigs sniffed an odor less when repeatedly presented (LMM: all odors P Conclusion: Collectively, pigs express sniffing, agonistic, and feeding-related behavior when exploring odors, which suggests that pigs perceive odors of non-social origin as a resource. Odors may thus constitute relevant enrichment material for pigs

Rub ‘n’ roll – Pigs, Sus scrofa domesticus, display rubbing and rolling behaviour when exposed to odours

Pigs are regarded as having a highly developed sense of smell, although scientific information on the topic is sparse. Here, we describe two behaviours unexpectedly observed in a study assessing pigs’ responses to odours and not previously reported in pigs. The study included 192 pigs of commercial breeds, tested in pairs with 12 different odours of non-social origin: 8 essential oils and 4 synthetic perfumes, plus an odourless control. Each odour was tested 24 times in triads of three odours. The results showed that, when exposed to odours, pigs display rubbing and rolling behaviour. Pigs displayed rubbing behaviour in 18 % of all odour exposures. Rolling behaviour was less frequent and displayed 7 times by five different pig pairs. Rubbing was always displayed following sniffing behaviour, and after a rubbing event, the pigs either performed sniffing behaviour (86.1 %), attempts at rolling (8.8 %) or a rolling event (5.1 %). Both males and females performed the rubbing behaviour (61 % female, 39 % male, Wilcoxon signed-rank test: W = 2199, P > 0.1), rolling behaviour (71 % female, 29 % male) and attempts at rolling (62 % female, 38 % male). Overall, essential oils (lavender, thyme, blood orange, aniseed, cedarwood, cinnamon bark, ginger, and pine) elicited more of the behaviours than the synthetic perfumes (vanilla, musk, apple, and jasmine) or the odourless control. All odours elicited rubbing whereas only four odours (blood orange, ginger, lavender, and pine) elicited rolling. Scent-rubbing/scent-rolling is a well-known behaviour in both wild (e.g., wolves and coyotes) and pet (e.g., cats and dogs) carnivores, although the function is not clear. This is the first report of rubbing and rolling as a response to an odour in pigs. The motivation for performing these behaviours is unknown but may include skin care, comfort behaviour or marking behaviour. Further studies allowing pigs physical access to rub and roll in different odours may elucidate the underlying motivation

Odor exploration behavior of the domestic pig (Sus scrofa) as indicator of enriching properties of odors

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