Wild boar: Sus scrofa

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The wild boar (Sus scrofa Linnaeus, 1758) is a large mammal belonging to the order Artiodactyla, family Suidae. Groves (1981) reported the existence of 16, possibly 17, subspecies of the genus Sus. According to Groves and Grubb (1993), the so called ‘Western races’ (S. s. scrofa and S. s. meridionalis) are known in Europe (Apollonio et al., 1988), S. s. algira in North Africa and S. s. lybicus in the Middle East extending at least as far east as Soviet Central Asia (S. s. attila and S. s. nigripes). The high sociality, reproductive potential, adaptability, sinantrophy, omnivory and other species specific features allow them adapting to different habitats. It is an adaptable species with a wide climatic tolerance. The Eurasian wild pig has one of the widest geographic distributions of all terrestrial mammals, and its range has been greatly expanded by human agency. Wild boar is widespread in most continental areas of Europe, and recently in Norway, with the exception of northern Fennoscandia and European Russia.

As a wild form, it has constituted a primary resource of subsistence hunters since the prehistorical times, and it is one of the most important targets for recreational hunting wherever it remains sufficiently or over abundant. Because its depredation on crops incurs a severe economic loss to communities, it is considered as a pest in many countries.

The main product is meat that represents the first source of game meat throughout Europe. The wild boar meat is largely consumed by the hunters and their families but a specialized market is developing in many countries. The main constraints to wild boar meat trade are the supply chain and the difficulty to fit the European regulation on food safety.

Although wild boar meat is considered safe and hygienically affordable due to its natural origin, the supply chain is often characterised by risks and critical points. Accordng to EFSA 2011, wild boar is a critical point when countries try to eradicate zoonotic diseases such as tuberculosis, brucellosis, yersiniosis and trichinellosis in humans, and important livestock infectious diseases such as pseudorabies and porcine circovirus-associated diseases (PCVADs) in pigs. At this purpose, proper handling of game meat from the field to the table and veterinary surveillance is extremely important.

As reported by Sales and Kotrba (2013) the microbiological quality of game meat will depend on: (1) microorganisms in the digestive tract and muscles of animals; (2) circumstances in which animals are killed; and (3) the conditions under which the carcasses are dressed. During storage of meat microflora development will be related to storage conditions and to biochemical characteristics of the meat (Gill, 2007).

Hygienic quality of game meat should be evaluated by both pathogenic bacteria presence and aerobic bacteria viable count (Avagnina et al., 2012). The aerobic bacteria viable count is usually higher in wild boar as compared to other wild species probably due to its habits (Avagnina et al., 2012). As no specific criteria are provided for wild animals’ meat the limit set by Regulation (EC) No 1441/2007 for meat from domestic animals (5 log cfu/cm2) is adopted.

It is interesting to highlight that aerobes and coliformes are lower in wild boar meat as compared to pork (Naya et al., 2003). This could be explained with the vacuum package storage of pork for extended periods, whereas wild boar meat was frozen or sold in a shorter time.

Also the location of a shot can affect bacteria contamination of muscle. Atanassova, Apelt, Reich, and Klein (2008) found values of 1.0–5.6 log10 cfu/cm2 for mesophilic aerobic plate counts and 1.7–3.5 log10 cfu/cm2 for the numbers of Enterobacteriaceae on muscles from different parts of wild boar. Higher values of counts were registered when the animals were shot at the digestive tract with carcass contaminated with faeces.

Studies performed by Avagnina et al., 2012 supported the hypothesis that lower aerobic viable counts and Enterobacteriaceae registered in chamois (Rupicapra rupicapra), roe deer and red deer hunted in the same region of wild boars were probably due to hunting methods (hiding vs. driven) or pre-slaughtering procedures.

According to Membré et al. (2011) Listeria monocytogenes is mainly related to meat processing contamination due to contaminated environment.

Another indicator of microbial quality is represented by Clostridium perfringes, mainly originating from the digestive tract and skin, indicating lack of hygiene during slaughtering and carcass handling.

The presence of nematode parasites as Trichinella spiralis in wild boar meat, have been reported from some countries in Europe, and North and South America (see Gill, 2007). Although the outbreaks of trichinellosis in humans, cooking wild boar meat until reaching a temperature of 77 °C (Greenbloom et al., 1997) is sufficient to inactivate this parasite. Despite plant material comprises near 90% in wild boar diet, they eat on animal matter including carrion and garbage available in the town neighbours. Thus, they could become infected if consume infectious cysts in raw meat.

Biosecurity measures for field dressing and meat inspection for Trichinella have been adopted in some EU countries (Latvia, Lithuania, Romania, Bulgaria and Slovakia ), where this infection have been detected in wild boar, and more in general in wildlife, even if the EU picture diverse.

As a general consideration Borilova et al., 2006 confirmed the importance of shooting that should be lethal and should avoid delay in bleeding, evisceration, chilling. These authors also confirmed that game meat has good microbiological and hygiene standard if storage regime, including temperature, is provided. However, due to rapid chemical changes of game meat, that play a role on the sensory parameters of the muscle, correct storage and temperature should be assured. These results deny the hypothesis about the short shelf life of game meat.

In a EU perspective the origin of the product, as to say traceability, because the possible uptake of contaminants is important due to the potential origin from polluted areas or local source of pollution. Heavy metals, elements that do not show an evident biochemical role, but could be toxic and accumulate in organs and tissue, such in tissues, such as cadmium (Cd), lead (Pb), mercury (Hg), arsenic (As), have been put in evidence in game meat or edible tissues above limits or passing tolerable intake. These limits (heavy metals) are passed in animals living close to mining sites or other pollution sources (Pokorny et al., 2009). This could be as a consequence of feeding on contaminated feeds, especially mushrooms or lichens (Reglero et al., 2008). Accumulation can increase with exposure (Falandysz et al., 2005). For some elements the higher accumulation capacity was registered in kidneys and skin, usually wasted, or liver that is sometime used for human consumption.

The health risk for meat consumers due to heavy metals is however considered negligible (Lazarus et al., 2008), and the contribution of heavy metals from wildlife has been decreasing in the last decades (Čelechovská et al., 2008).

On the other hand, the Pb contamination due to the residuals of bullets in the muscle area along the bullet pathway should not be neglected (Hunt et al., 2006). At this purpose it is necessary an accurate trimming of the carcass around wounds and bullet pathways (Doborowolska and Melosik, 2008).

Organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs) are widely used in agricultural practices, and generally accumulate in fat of mammals (Guruge et al., 2004). These organic compounds are related to different toxic effects, are considered are endocrine disruptors and inducing cancerogenesis (Campbell and Campbell, 2001). Although PCB legal limits (Regulation (EC) 1881/2006 European Commission, 2006) in meat and offal of wild animals are rarely overcome the attention of the public opinion and institutions is increasing.

Scarce data are available on the presence of mycotoxins in wild animal meat or the food chain (Deutz et al., 2000).

The Chernobyl disaster in 1986 needs a specific focus. The accident implied a fallout of different elements, contaminating meat of wild ungulates in various countries; northern Europe, Austria and eastern Germany and probably eastern Italian Alps. Ungulate meat contamination by 137Cs (caesium) was followed by a decay although showing seasonal peaks (Fielitz et al., 2009). These peaks are mainly related to diet composition according to feeding habits; for roe deer contamination was higher in autumn (Fielitz et al., 2009), for wild boar was higher in summer declining in autumn and winter (Hohmann and Huckschlag, 2005). It is important to highlight that large part of roe deer and wild boar (Strebl and Tataruch, 2007) harvested in highly contaminated areas exceed the EU threshold for foodstuffs of 600 Bq radiocaesium per kg of fresh meat.

Since entering the eastern EU at the start of 2014, African swine fever (ASF) has spread locally (Poland, Latvia, Lithuania, Estonia) in the wild boar population, independently of outbreaks in domestic pigs. The risk of African swine fever (ASF) as a re-emerging disease was emphasized by the EU (COMMISSION IMPLEMENTING DECISION, 2014/178/EU). Since ASF is a highly contagious and fatal disease of domestic pigs and wild boar, transmitted through direct contact, ingestion, and certain tick species, restriction to movement and trade of animals including semen and products was adopted for some re-emerging or endemic presence areas.

 

ID&ECOLOGY

 

The wild boar presence is observed in a wide variety of habitat, from semi-desert areas to tropical rain forests and boreal forests, temperate woodlands, grasslands, agricultural land to feed on crops. In Europe, it mainly occupies broadleaf forests, Mediterranean shrublands, coniferous forests and farmland, close to tree cover (Spitz 1999).

Although the species is omnivorous it mainly feeds on vegetable matter: fruits, seeds, roots and tubers, account for more than 90% of the diet (Spitz, 1986; Belova, 2015). The feeds of animal origin are represented by earthworms, molluscs, crabs and other arthropods and even fishes and eggs. Occasionally feeds on invertebrate and small vertebrate. It is reported to predate larger vertebrate puppies, but the opportunistic use of carcasses is not neglected.

The basic social unit accounts one or more females and striped piglets of the last litter and also include subadults of the previous season. The family groups are called sounders. Male subadults retreat from the sounder at 18 months of age. Adult males tend to stay alone or in little groups of two three individuals but always relatively close to the main group or together during the mating season.

Although the species is seasonal, reproduction is positively correlated with food availability and climate. Social organization of the group is reported to play a role in modulating reproductive activity as for synchronizing the oestrus.

Oscillating trend in the numbers of wild boars harvested by hunters suggest strong fluctuations in the numbers of animals. Due to the high reproductive capacity the abundance of population mainly depends on litter size (4 to 7 piglets) and fertility of females, but is also influenced by juvenile mortality, both of which factors may be influenced by the availability of foodstuffs and climate. The principal causes of mortality are predation (mainly for piglets), and disease being hunting removal the main cause.

 

MANAGEMENT

As a wild form wild boar represent a primary resource for recreational hunting wherever it remains sufficiently or over abundant. The increasing trend observed in many European Countries.

Wild boar increased consistently throughout Europe in the last three decades, while the number of hunters remained stable or declined in most countries. Different management strategies have been adopted in European countries including hunting harvesting and containment programs. It is probable that recreational hunting is unable to limit wild boar population growth if appropriate strategies of containment are not adopted. Notwithstanding factors as climate (mild winters and rainy spring), reforestation, supplementary feeding provided in some periods, etc. play a role in the population increase.

 

TRADE

 

Large differences in consumption across countries are certainly influenced by culture, traditions, food habits, etc. As an example the investigation on consumption of farm animals (Kjaernes et al, 2008) can be cited. The survey carried out found that “ … the majority in Scandinavia see venison very appealing, the opposite is the case in countries like The Netherlands, Britain and Italy.” This is certainly due to different concepts of edible species, wild species and pets in different cultures. Tickle (2016) focuses the attention on the differences between rural and urban communities, being the first “ …more supportive of hunting than urbanites because of their closer contact with and direct consumptive use of natural resources and wildlife.” Often game meat is supposed to be a sort of delicacy among traditional foods.

Hungarian culture, as well, presents very old traditions in which several recipes are devoted to the game meat and widely appreciated (Bodnar et al, 2014).

The attitude toward natural resources, however, can be interpreted in different ways. Some of the consumers have a strong attitude toward game meat consumption due to its origin from natural areas which often implies the idea of safety and not contaminated food.

Bodnar et al (2014) found that among Hungarian consumers involved in the survey about 90% considered game meat as healthy and almost organic food. Similar investigation in Finland found that the purchased amounts of minced meat and pork have declined between 1998 and 2006, however the amounts of poultry, venison and other game meat have increased (Koistinen L. 2010).

At European level statistics rarely seem to be affordable on consumption of game meat, and the only available survey is conducted among the members of Slow Food, showing that at the European level, 49% also feeds on wild game meat (Ghione et al., 2013). This result is probably overestimated if it applies to the rest of the population, as adherents of this association are more interested to alternative and niche products than the rest of the population.

The safety of game meat, however, is often rejected by scientific contributes devoted to the investigation of potential toxic elements presence. This is the case of pollutant elements that can concentrate along the food chain, and the possibility of human infection by several diseases (Ramanzin 2010), even if this aspect seems to be widely unknown by consumers, as reported by Bodnar (2014) who found that only 2% of the respondent in the survey carried out was aware about this.

Other consumer groups, on the contrary, are against hunting activities tout court mainly for wildlife preservation and well-being considerations, and consequently don’t eat venison rejecting the concept of cruelty that hunting activities may imply. This occurrence is found in some studies that investigate the importance of labelling referring to the area of origin in food attributes and the preference for organic and animal welfare-oriented food (among others, Pouta et al. 2010). The opinions on the subject are not unanimous, as shown by Tickle (2016) that mentions an increase of the popularity of the game meat as a consequence of the “ ….rising in organic and health trend.” supporting the position of Ljung (2014).

The picture is even more scattered if other traditions are taken into account, as shown by Peterson et. al (2010) that support the idea that hunting is a sustainable form of nutrition and “cruelty free” if compared with the animals killed during fields’ cultivation operations.

 

Eurostat import/export per capita 2015 – based on EUROSTAT figures

COUNTRY SPECIFICS

As mentioned above, Wild Boar disappeared from the British Isles and Scandinavia in the 17th century, although it has now been reintroduced to Sweden and escaped animals have established themselves in the wild in Britain (Spitz, 1999). There are at least three small Wild boar populations in England, on the Kent/East Sussex border, in Dorset, and in Hereford (Battersby, 2005).

Wild boar is native to Corsica and Sardinia, but the population in Sicily was introduced (Spitz, 1999).

However, the recent distribution of the species shows that wild boars have settled in areas with harsher climate than is found in most parts of Norway. Wild boars have largely increased in numbers and distribution during the recent decades and are now entering south-east Norway (Rosvold and Andersen, 2008). Human support (e.g. supplementary feeding) has allowed the wild boar to persist in areas that may have been inhabitable before. In Lithuania wild boar is most abundant in areas of high soil fertility (Belova, 2015). Coniferous forests, especially spruce stands are mostly preferred and deciduous forests are more important in summer not only for foraging but also for bathing (Belova O. xxxxx).

S. scrofa has by far the largest range of all pigs. It occurs throughout the steppe and broadleaved forest regions of the Palaearctic, from western Europe to the Russian Far East, extending southwards as far North Africa, the Mediterranean Basin and the Middle East, through India, Indo-China, Japan (including the Ryukyu Chain), Taiwan and the Greater Sunda Islands of South-east Asia. Populations east of Bali are probably all introduced. It has been extinct in the British Isles since sometime in the 17th century, despite attempted introductions of new stock from Europe (Harting, 1880) (though see below for more recent information). It is also extinct in southern Scandinavia (but see below), over extensive portions of its recent range in west-central and eastern parts of the former Soviet Union (Heptner et al., 1961), and in northern Japan (Chiba, 1964, 1975). The species was last reported in Libya in the 1880s, and it became extinct in Egypt in about 1902 (Hufnagl, 1972).

 



Short video on Wild boar in Britian from http://www.britishwildboar.org.uk/


Wild boar with piglet into the italian countryside

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