Opinion paper: What needs to be changed for successful future livestock farming in Europe?

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Possible mechanisms of host resistance to Haemonchus contortus infection in sheep breeds native to the Canary Islands

Haemonchus contortus appears to be the most economically important helminth parasite for small ruminant production in many regions of the world. The two sheep breeds native to the Canary Islands display distinctly different resistant phenotypes under both natural and experimental infections. Canaria Hair Breed (CHB) tends to have significantly lower worm burden and delayed and reduced egg production than the susceptible Canaria Sheep (CS). To understand molecular mechanisms underlying host resistance, we compared the abomasal mucosal transcriptome of the two breeds in response to Haemonchus infection using RNAseq technology. The transcript abundance of 711 and 50 genes were significantly impacted by infection in CHB and CS, respectively (false discovery rate <0.05) while 27 of these genes were significantly affected in both breeds. Likewise, 477 and 16 Gene Ontology (GO) terms were significantly enriched in CHB and CS, respectively (P < 1.0 × 10(−4)). A broad range of mechanisms have evolved in resistant CHB to provide protection against the parasite. Our findings suggest that readily inducible acute inflammatory responses, complement activation, accelerated cell proliferation and subsequent tissue repair, and immunity directed against parasite fecundity all contributed to the development of host resistance to parasitic infection in the resistant breed

World Association for the Advancement of Veterinary Parasitology (WAAVP): Second Edition of Guidelines for Evaluating the Efficacy of Anthelmintics in Poultry

This revision of the original poultry guidelines has been prepared to assist in the planning, conduct and interpretation of studies designed to assess the anthelmintic efficacy of drugs (newly discovered or currently used) against helminth parasites of chickens and turkeys. The original set of poultry guidelines was published in 2003. The current version provides an update on procedures to study and quantify the most important helminth parasites of chickens and turkeys, and to integrate these poultry guidelines with a new series of general, reflective and host-specific guidelines relative to assessing anthelmintic efficacy in production and companion animals. General considerations required for the conduct of studies designed to evaluate anthelmintics regardless of animal host such as the selection of study animals, animal housing, feeding, study design, record keeping and statistical analysis are for the most part provided in the newly published general guidelines. Taken together, the general and poultry guidelines should help investigators and others design and conduct studies and evaluate data concerned with determining the efficacy and safety of anthelmintics in chickens and turkeys. Additionally, this revision draws attention to several timely considerations inherent to anthelmintic evaluations such as the need to properly collect helminth specimens for subsequent determinations (e.g. species and stage verification, helminth genotyping). The investigations addressed herein, will most likely provide the very first public record of a new product\u27s abilities to effectively reduce targeted, helminth infections in animals, and particular attention should be focused on study excellence and accuracy. Due to changes in consumer preferences, and new regulatory requirements, poultry husbandry, especially regarding laying hens, has changed immensely in many countries since the publication of the first poultry guidelines. These changes have generally allowed for a much greater exposure of birds to the source of helminth challenge (litter and fields as opposed to cages). Parasitic helminthiosis of poultry has therefore greatly increased in incidence and magnitude; changes that accentuate the need for more effective anthelmintic intervention and an update on the means of determining anthelmintic efficacy

Lamb survival and ewe longevity in a crossbreeding program between indigenous and exotic sheep in semi-arid lands

The survival of lambs and longevity of ewes within flocks are important for the sustainability of sheep populations especially in arid and semi-arid lands (ASAL). In this study we conducted pre- and post-weaning survival analysis of lambs and the longevity of ewes of indigenous pure Red Maasai (RRRR), pure Dorper (DDDD), and their crosses comprising F1 (DDRR) and 75 %Dorper-25 %Red Maasai (DDDR) using Cox and Weibull proportional hazard models. The objective was to determine the genetic and non-genetic factors affecting lamb survival to yearling as well as ewe longevity. Data comprised records on 6313 lambs and 2003 ewes. Overall pre-weaning mortality was lower (5 %) compared to post-weaning mortality rate (17 %). Lambs born during the long dry season had a higher risk of dying than those born during the wet seasons. For both lambs and ewes, the Dorper had the highest risk of dying or being culled. Among the crossbreds, the DDDR lambs and ewes had higher risks of dying or being culled relative to F1 lambs and ewes. The risk of ewes being culled reduced with increasing age at first lambing and parity. Heritability estimates for pre-weaning mortality were higher (0.10–0.14) than post-weaning mortality (0.01–0.05). The higher heritability for pre-weaning lamb survival in indicates greater genetic variation, presenting an opportunity for selection for lamb survival. Interventions to improve the production environment in the ASAL areas would also improve the survival of lambs and longevity of ewes.</p

Gastrointestinal nematode infections in German sheep

The objective of the present study was to determine the prevalence and variation of natural gastrointestinal nematode (GIN) infections in lambs according to birth type, gender and breed based on individual faecal egg counts (FEC) from various regions in Germany. A total of 3,924 lambs (3 to 15 months old) with different genetic backgrounds (Merinoland, German Blackhead Mutton, Rhoen, Texel and Merino long-wool) were individually sampled during the grazing period between 2006 and 2008. Furthermore, pooled faecal samples from each of the farms were cultured in order to differentiate the third-stage larvae of the nematode spp. Sixty-three percent of the lambs were infected with GIN. The infections were mostly low to moderate and involved several nematode species. The Trichostrongylus spp. was the predominant species based on the percentage of larvae in faecal cultures. Only 11.4% of the lambs were free of Eimeria oocysts. Tapeworm eggs were encountered in 13.2% of all samples. The prevalence of GIN infections varied significantly (P < 0.001) among farms. A significantly higher FEC (P < 0.05) was observed in multiple-born lambs when compared with singletons. Moreover, male lambs were more susceptible to infection than females (P < 0.001). No significant differences (P > 0.05) were observed between breeds regarding FEC. Inter-individual variations were higher than inter-breed differences, which may indicate the possibility of selection within these breeds for parasites resistance as described in earlier studies

The immunology and genetics of resistance of sheep to Teladorsagia circumcincta

Teladorsagia circumcincta is one of the most economically important gastrointestinal nematode parasites of sheep in cool temperate regions, to which sheep show genetically-varying resistance to infection. This is a very common parasite and viable sheep production requires the extensive use of anthelmintic drugs. However, the emergence of drug-resistant parasites has stimulated the search for alternative control strategies to curb production losses. Lambs become infected soon after weaning and begin to control parasite burden within 8-10 weeks of continual infection. This control is an acquired characteristic mediated by the development of parasite-specific antibodies. This paper describes the immunology associated with resistance and susceptibility, focussing on differential T cell activation that regulates the production of specific effector mechanisms. It continues by summarizing the methods used to identify genes that could be exploited as molecular markers of selection for resistance. In particular it focusses on the link between understanding the molecular immunology of infection and the identification of candidate genes for selection

Microtubule inhibition as a proposed mechanism for the anthelmintic effect of phytochemicals isolated from Cicerbita alpina

The alpine plant Cicerbita alpina (L.) Wallr., when grown as a sprout, is known as a bitter-tasting culinary delicacy. Recently it has also been reported to have anthelmintic activity, prompting further investigation into its mechanism of action. Liquid-liquid fractions were prepared from a methanolic extract of the aerial parts and were submitted in parallel to embryo development (ED), worm motility (WMT), and cytotoxicity assays for anthelmintic and toxicity evaluations. The anthelminthic assays revealed the more polar fractions to be most active against Ascaridia galli embryos (BuOH | 68% ED | c = 500&nbsp;μg/ml and EtOAc | 65% ED | c = 500&nbsp;μg/ml) and Caenorhabditis elegans adult worms (BuOH | 49% WMT | c = 150&nbsp;μg/ml and EtOAc | 74% WMT&nbsp;| c = 150&nbsp;μg/ml) suggesting the fraction's constituents possess dual anthelmintic activity against multiple life-cycle stages (i.e., eggs, worms) of helminths. Additionally, the BuOH fraction was non-cytotoxic to human cell-lines. Subsequent FCC and SEC derived subfractions were submitted to the anthelmintic assay workflow and the enriched subfractions B1 and E3.8, phytochemically assigned as 11-β,13-dihydrolactucin and luteolin, demonstrated bioactivity against the embryo phenotype (B1 | 58% ED | c = 1.8&nbsp;μM and E3.8 | 46% ED | c = 1.7&nbsp;μM) within range of the flubendazole control. Furthermore, luteolin was found to inhibit C. elegans egg hatching (luteolin | 65% EH | c = 10&nbsp;μM | t = 10&nbsp;h) within the range of the control albendazole. Both identified anthelmintic phytochemicals were found to affect tubulin polymerisation at a concentration of c = 50&nbsp;μM. Together with in silico virtual screening studies, these results suggest microtubule stabilisation as a possible anthelmintic target and mechanism of action. This work effectively advocates the consideration of C. alpina extracts and fractions for the development of herbal therapeutics against parasitic helminth

Advancing leadership in surgery : a realist review of interventions and strategies to promote evidence-based leadership in healthcare

Background: Healthcare systems invest in leadership development of surgeons, surgical trainees, and teams. However, there is no agreement on how interventions should be designed, or what components they must contain to be successful. The objective of this realist review was to generate a programme theory explaining in which context and for whom surgical leadership interventions work and why. Methods: Five databases were systematically searched, and articles screened against inclusion considering their relevance. Context-mechanism-outcome configurations (CMOCs) and fragments of CMOCs were identified. Gaps in the CMOCs were filled through deliberation with the research team and stakeholder feedback. We identified patterns between CMOCs and causal relationships to create a programme theory. Results: Thirty-three studies were included and 19 CMOCs were developed. Findings suggests that interventions for surgeons and surgical teams improve leadership if timely feedback is delivered on multiple occasions and by trusted and respected people. Negative feedback is best provided privately. Feedback from senior-to-junior or peer-to-peer should be delivered directly, whereas feedback from junior-to-senior is preferred when delivered anonymously. Leadership interventions were shown to be most effective for those with awareness of the importance of leadership, those with confidence in their technical surgical skills, and those with identified leadership deficits. For interventions to improve leadership in surgery, they need to be delivered in an intimate learning environment, consider implementing a speak-up culture, provide a variety of interactive learning activities, show a genuine investment in the intervention, and be customised to the needs of surgeons. Leadership of surgical teams can be best developed by enabling surgical teams to train together. Conclusions: The programme theory provides evidence-based guidance for those who are designing, developing and implementing leadership interventions in surgery. Adopting the recommendations will help to ensure interventions are acceptable to the surgical community and successful in improving surgical leadership. Trial registration: The review protocol is registered with PROSPERO (CRD42021230709)