Attractants for wild pigs: current use, availability, needs, and future potential

Effect of different odors on the fighting behavior of weaning piglets after merging into a large pen

In intensive pig production, the fighting behavior of weaning piglets after merging pens is relatively common. Fighting behavior not only easily causes injury in pigs but also affects the production performance of pigs. To reduce fighting behavior in farms, this study aimed to explore the possible effect of odorous substances on piglet fighting behavior after merging into a large pen. Six different sprays were tested: original creamy, cheese flavor, orange flavor, truffle, vanilla and pigpen flavor. In each experiment, two groups were set (one odor-sprayed and no sprayed control), and 12 pigs were used per group. After mixing, the frequency of occurrence of various piglet behaviors in different pens was recorded. During this period, salivary cortisol levels and skin lesion scores were evaluated. As a result, the piglets sprayed with the original creamy, cheese flavor and vanilla substances obtained significantly higher average daily gain and feed intake and showed a significantly lower incidence of fighting behavior, and the skin lesion score and salivary cortisol of piglets were also reduced significantly. All the other odorous substances had no significant effects on the fighting behavior and production performance of piglets.

Pigs' management practices and exposure to Trichinella spp. in pigs and warthogs in the northern area of Senegal

Background and Aim:

Trichinellosis is a neglected and emerging foodborne zoonosis in Africa. Trichinella infection occurs through the consumption of raw or undercooked infected meat and meat products. This study aimed to assess pigs’ management practices and determine the exposure of pigs and warthogs to Trichinella spp. in the northern area of Senegal.

Materials and Methods:

Surveys and observations were carried out among 40 pig farmers to assess husbandry practices regarding Trichinella spp. life cycle. In addition, 201 pig meat juices and 83 warthog meat juices were extracted and tested for anti-Trichinella antibodies by indirect enzyme-linked immunosorbent assay.

Results:

Most (97%) of farms practiced a traditional farming system with free-ranging of pigs in 85% of farms. Farms had local pig breed without housing and supplementary feeding. Some farmers (27.5%) used slaughter waste to feed pigs and farmers were not aware that free-range farming is a source of infection to Trichinella infection. They were also unaware that some pig diseases could be transmitted to humans. The seroprevalence of Trichinella infection was 10.9% (95% confidence interval [CI]: 6.6–15.2%) in pigs and 10.8% (95% CI: 4.16–17.52%) in warthogs with significantly higher seroprevalence in male (22.2%: 95% CI: 6.6–37.8%) compared to female (9.2%; 95% CI: 4.9–13.5%) (p < 0.05).

Conclusion:

The confirmation of exposure to Trichinella spp. in this area in pigs and warthogs shows a significant risk of transmission of this disease to humans if the farming conditions and the health surveillance system are not respected. However, control measures are needed to reduce any risk of transmission of Trichinella infection to humans.

Stable carbon and nitrogen isotope values in hair reveal management differences and hidden practices in wild boar populations

The analysis of stable isotopes in different tissues has been widely used to obtain information on the ecology and nutritional patterns of wildlife. The isotope ratios of the stable isotopes of carbon and nitrogen (δ¹³C and δ¹⁵N) analysed in different tissues are directly related to the animal's diet and, to some extent, to the environment where the individual has growth. Specifically, this type of analysis in hair samples has become relevant as it provides information on the quality and long-term composition of the diet that produced the isotope accumulation during the tissue growth. We took samples of wild boar (Sus scrofa) hair from 7 different populations in the south-west of Spain (Mediterranean habitats), in the 2018/2019 hunting season. The main objectives of this study were (i) to investigate the use of hair stable isotopes to reveal differences in composition and quality of the diet of wild boar within the same population or between populations, and (ii) to use hair isotopes as a tool to uncover hidden management practices that may occur in hunting areas associated with the use of supplementary feeding or even captive breeding and release. Each animal had a hair (long 10 cm) analysed in duplicate, previously cut into parts of equal size (from the oldest part of the hair to the most recent part), that were analysed separately. We found differences in δ¹³C and δ ¹⁵N between hair parts and populations, which can be related to management actions at different times during the hair growth. Moreover, the use of corn, a type of plant not occurring naturally in the study area, can be documented with the isotope analysis to prove unauthorized supplementary feeding or captive origin of wild boar in hunting areas.

Research priorities to fill knowledge gaps in wild boar management measures that could improve the control of African swine fever in wild boar populations

The European Commission asked EFSA to provide study designs for the investigation of four research domains (RDs) according to major gaps in knowledge identified by EFSA in a report published in 2019: (RD 1) African swine fever (ASF) epidemiology in wild boar; (RD 2) ASF transmission by vectors; (RD 3) African swine fever virus (ASFV) survival in the environment, and (RD 4) the patterns of seasonality of ASF in wild boar and domestic pigs in the EU. In this Scientific Opinion, the second RD on ASF epidemiology in wild boar is addressed. Twenty-nine research objectives were proposed by the working group and broader ASF expert networks and 23 of these research objectives met a prespecified inclusion criterion. Fourteen of these 23 research objectives met the predefined threshold for selection and so were prioritised based on the following set of criteria: (1) the impact on ASF management; (2) the feasibility or practicality to carry out the study; (3) the potential implementation of study results in practice; (4) a possible short time-frame study (< 1 year); (5) the novelty of the study; and (6) if it was a priority for risk managers. Finally, after further elimination of three of the proposed research objectives due to overlapping scope of studies published during the development of this opinion, 11 research priorities were elaborated into short research proposals, considering the potential impact on ASF management and the period of one year for the research activities.

Predicting functional responses in agro-ecosystems from animal movement data to improve management of invasive pests

Functional responses describe how changing resource availability affects consumer resource use, thus providing a mechanistic approach to prediction of the invasibility and potential damage of invasive alien species (IAS). However, functional responses can be context dependent, varying with resource characteristics and availability, consumer attributes, and environmental variables. Identifying context dependencies can allow invasion and damage risk to be predicted across different ecoregions. Understanding how ecological factors shape the functional response in agro-ecosystems can improve predictions of hotspots of highest impact and inform strategies to mitigate damage across locations with varying crop types and availability. We linked heterogeneous movement data across different agro-ecosystems to predict ecologically driven variability in the functional responses. We applied our approach to wild pigs (Sus scrofa), one of the most successful and detrimental IAS worldwide where agricultural resource depredation is an important driver of spread and establishment. We used continental-scale movement data within agro-ecosystems to quantify the functional response of agricultural resources relative to availability of crops and natural forage. We hypothesized that wild pigs would selectively use crops more often when natural forage resources were low. We also examined how individual attributes such as sex, crop type, and resource stimulus such as distance to crops altered the magnitude of the functional response. There was a strong agricultural functional response where crop use was an accelerating function of crop availability at low density (Type III) and was highly context dependent. As hypothesized, there was a reduced response of crop use with increasing crop availability when non-agricultural resources were more available, emphasizing that crop damage levels are likely to be highly heterogeneous depending on surrounding natural resources and temporal availability of crops. We found significant effects of crop type and sex, with males spending 20% more time and visiting crops 58% more often than females, and both sexes showing different functional responses depending on crop type. Our application demonstrates how commonly collected animal movement data can be used to understand context dependencies in resource use to improve our understanding of pest foraging behavior, with implications for prioritizing spatiotemporal hotspots of potential economic loss in agro-ecosystems.