VetAgro Sup

Animal welfare was initially conceived as the absence of negative experiences. More recently, the importance of positive affects was recognised. This suggests a continuum from very poor welfare, where suffering predominates, to very good welfare, where positive affects predominate, and that the intrinsic hedonic value of the environment, i.e. whether it is pleasant or not, determines the level of welfare an animal can reach on this continuum. In this paper, we question whether environments with a high intrinsic hedonic value are enough to allow good welfare. For instance, pleasant but monotonous environments can induce boredom, which is likely to affect animals negatively. By contrast, complex environments can encourage engagement. In addition, the possibility to act freely and efficiently plays a role. Environments that limit behavioural expression or make behaviour inefficient can lead to frustration and apathy. By contrast, environments that give freedom of action and make these actions efficient encourage animals to exert their agency - through choices, control, problem solving, free action, or exploration. We argue that intrinsic hedonic value, complexity, and possibility for action all contribute to welfare. However, a constant high level of hedonic value may result in a decrease in the hedonic value perceived by the animal. An overly complex environment or one that affords too wide a variety of actions may overwhelm animals. Therefore, rather than being maximised, hedonic value, complexity, and possibility for action need to be optimised to maximise animal welfare. Where the optimum sits varies between individuals depending on factors such as species, age, physiological status, or individual traits.

Volatile organic compounds (VOCs) act as mediators in plant communication, pollination, and plant defense against herbivory. The set of VOCs in an environment constitutes the volatilome, and it may contain valuable information for understanding ecosystem functioning. Here we set out to obtain a representative inventory of VOCs such as those that a bee might encounter while foraging in grazed permanent grasslands. We chose the passive diffusion trapping (PDT) method, because this method, designed for this type of measurement in large air volumes, is the easiest to implement. We thus exposed Tenax TA sorbent tubes to air over the daytime on nine different plots at five periods during the vegetation cycle. GC-MS analysis after thermal desorption detected more than 100 VOCs encompassing a broad diversity of chemical families, with oxygenated compounds (alcohols, ethers, carbonyls, esters) and alkanes dominating in terms of number of compounds as well as total relative area, benzenoids and terpenes being also abundant. For subsets of observations, we checked if solid-phase microextraction using polydimethylsiloxane-carboxen-divinylbenzene fiber coatings, or active-mode trapping (AcT) using a pump that enabled a highly controlled volumes of air to cross the Tenax tubes should be preferred to PDT. Compared to the two passive sampling methods for the same observations, the AcT method, which collected the greatest diversity of compounds and the highest number of known semiochemicals, seemed best suited to monitoring the grassland chemical landscape.

Thank you for giving us the opportunity to respond to comments from readers regarding our recent publication, “Risk factors for recurrence of Giardia duodenalis infection in dogs: a case–control study.” We appreciate the interest shown in our work. The readers raised several insightful points, all of which were emphasised in the discussion of our study, although further reflection is certainly warranted. We agree that the significant association identified between retrievers and recurrence of giardiasis in our study is more likely attributable to selection bias than to a true breed predisposition. Although we did not thoroughly stratify breeds by housing conditions, we observed that retrievers in our study population were significantly more likely than other breeds to live in mixed housing environments. Given that most retrievers lived in community settings and considering the significant association found between giardiasis recurrence and non-household environments, it would be inappropriate to suggest a genetic susceptibility without further evidence. We also believe that the use of probiotics at the time of initial diagnosis may reflect clinicians’ perceptions of disease severity and complexity, influencing their decision-making to optimise recovery, rather than indicating probiotics as a true risk factor for recurrence. This is the most plausible explanation we could find for this unexpected association, which seems contrary to logic (a neutral or favourable effect was initially hypothesised). To the best of our knowledge, only one prospective study has assessed the role of probiotics in treating chronic, naturally acquired giardiasis in dogs, and it failed to demonstrate any difference in cyst shedding compared with a placebo (Simpson et al., 2009). The role of probiotics in preventing and managing giardiasis in dogs remains unclear and merits further investigation. We understand the concerns raised about the diagnostic method used to detect Giardia duodenalis infection in our study. Although microscopy following zinc sulphate flotation is a historically used method for diagnosing giardiasis in dogs, its performance is limited, and poor sensitivity has been reported even when analysing three consecutive stool samples (Rishniw et al., 2010; Symeonidou et al., 2020). While reduced sensitivity may have resulted in false negatives and misclassification of some cases in our study, we deliberately opted for faecal flotation alone to identify entire parasites, rather than detecting soluble coproantigens or DNA, in order to confirm active infection. Furthermore, retesting with faecal antigen tests is not currently recommended for dogs with persistent gastrointestinal signs after giardiasis treatment, as antigens can remain detectable in faeces even after successful therapy (Strand et al., 2008), potentially leading to false positives and further misclassification. Another pitfall of such diagnostic follow-up would be overlooking an underlying chronic inflammatory enteropathy that is responsible for the persistence or recurrence of gastrointestinal signs by focusing on test positivity. Finally, we believe that the association found between concurrent or underlying chronic inflammatory enteropathy and giardiasis recurrence represents a key finding of our study. Although treatment failure due to chemoresistance is of emerging concern and difficult to address in clinical practice, considering alternative therapeutic strategies, such as nutritional intervention, may offer valuable benefits in dogs with persistent diarrhoea who remain positive for Giardia despite appropriate antiparasitic treatment. K. Mourou: Conceptualization; visualization; validation; writing – review and editing; writing – original draft. The author declares no conflict of interest.

Aquaculture is the fastest-growing animal food-producing sector for human consumption globally. Increasing population size, density, and interconnectivity among farms are expected to markedly increase disease outbreak risks, threatening sector sustainability. Infectious diseases cause around a third of observed mortality in farmed salmon in Norway. Cardiomyopathy syndrome (CMS), caused by piscine myocarditis virus (PMCV), is one of the most frequently detected diseases and often causes high mortality in the late phase of salmon production, compromising fish welfare and causing significant economic losses. Despite its impact, the limited understanding of PMCV dispersal and its drivers hampers effective risk mitigation interventions. To address this, we generated one of the largest genomic datasets for any aquatic viral pathogen, focusing on PMCV collected from Scotland (United Kingdom) and Norway. Combined with detailed metadata, this enabled one of the most comprehensive phylodynamic analyses of a fish virus. Phylodynamic analyses reveal that PMCV likely emerged in farmed salmon concurrent with the global expansion of aquaculture, with a most recent common ancestor around the 1970s-1990s. We identify a distinctive national clustering of virus genomes, reflecting intranational spread interspersed with multiple introductions of distinct PMCV lineages into Scotland. We assess factors influencing virus spread, highlighting the importance of geographic proximity and at-sea farm density, and the possible role of boat connectivity in facilitating long-distance dispersal events. Overall, our study emphasizes the importance of viral genomics in understanding the evolutionary and dispersal dynamics of aquatic pathogens and informs targeted biosecurity strategies to mitigate the growing risk of viral disease in expanding aquaculture systems.