No abstract

No abstract

Particle passage from the reticulorumen (RR) depends on particle density and size. Forage particle density and size are related and change over time in the RR. Particle density mainly influences sorting in the reticulum, whereas particle size influences particle retention in the fibre mat of stratified rumen contents ('filter-bed' effect). We investigated these effects independently, by inserting plastic particles of different sizes (1, 10 and 20 mm) and densities (1·03, 1·20 and 1·44 mg/ml) in the RR of cattle (Bos primigenius f. taurus) as a pilot study, and of muskoxen (Ovibos moschatus; n 4) and moose (Alces alces; n 2) both fed two diets (browse and grass). Faeces were analysed for plastic residues for 13 d after dosing to calculate mean retention times (MRT). The results confirmed previous findings of differences in absolute MRT between species. Comparing muskoxen with moose, there was no difference in the effect of particle density on the MRT between species but particle size had a more pronounced effect on the MRT in muskoxen than in moose. This indicated a stronger 'filter-bed effect' in muskoxen, in accord with the reports of stratified RR contents in this species v. the absence of RR content stratification in moose. Low-density particles were retained longer in both species fed on grass diets, indicating a contribution of forage type to the 'filter-bed effect'. The results indicate that retention based on particle size may differ between ruminant species, depending on the presence of a fibre mat in the RR, whereas the density-dependent mechanism of sedimentation in the RR is rather constant across species.

The obligatory, periodic regurgitation of forestomach material and its subsequent re-mastication is the hallmark of the most diverse extant large herbivore group, the ruminants. Although the process of rumination is well understood in domestic species, differences between free-ranging wild ruminant species, for example of different body size or different feeding type, remain speculative to date. Here we investigate the proportion of plastic particles of varying size (1, 10 and 20mm) and density (1.03, 1.20 and 1.44 mg/ml) that are recovered intact or ruminated-upon after insertion into the reticulorumen (RR) of domestic cattle (Bos primigenius f. taurus) on grass silage, and of muskoxen (Ovibos moschatus; n = 4) and moose (Alces alces; n = 2) both fed browse and grass diets. In the three species, the proportion of particles leaving the RR intact depended on particle size, with density showing no effect in this study. The major proportion of 1mmparticles was excreted intact, whereas intact 10-20mmparticles were only excreted sporadically, and not in all animals. Intact particles were mostly found in the initial samples after marker application, and mean retention times of intact particles were always shorter than those of ruminated particles. There were no differences between moose and muskoxen, but diet had a significant effect, with a higher proportion of 1mm particles ruminated upon on the grass diet in both species, indicating a higher 'filter-bed effect' with entrapment of small particles in a fibre mat in the RR on a grass diet. Given that less particles were ruminated on the grass diet, one could either assume that free-ranging browsers ruminate less than grazers on similar food intakes (or that they have higher food intakes at similar levels of rumination). The existing data on time-budgets of free-ranging ruminants, however, does not suffice to test these hypotheses. The fact that indication of a 'filter-bed effect' was also detectable in moose raises the question whether adaptations described in 'cattle-type' ruminants really serve to re-inforce the processes of RR contents stratification and the 'filter-bed', or whether they are not rather directed at other aims, such as maximizing microbial yield from the RR. Abstract 17The obligatory, periodic regurgitation of forestomach material and its subsequent re-18 mastication is the hallmark of the most diverse extant large herbivore group, the ruminants. 19Although the process of rumination is well understood in domestic species, differences 20 between free-ranging wild ruminant species, for example of different body size or different 21 feeding type, remain speculative to date. Here we investigate the proportion of plastic 22 particles of varying size (1, 10 and 20 mm) and density (1.03, 1.20 and 1.44 mg/ml) that are 23 recovered intact or ruminated-upon after insertion into the reticulorumen (RR) of domestic 24 cattle (Bos primigenius f. taurus) on grass silage, and of muskoxen (Ovibos moschatus; n=4) 25 and moose (Alces alces; n=2) both fed bro...

Antimicrobial resistance (AMR) is an emerging global health concern, affecting both the animal and the human population. Transmission pathways of AMR are therefore abundant and complex, and ways to prevent or reduce transmission to consumers must be identified. The overall goal of this study was to define the content of an intervention study aimed at reducing the transmission of AMR from animal sources to humans. To identify the most relevant pathways, Swiss experts and consumers were interviewed about their opinions on the risks of transmission of AMR. Opinions of experts and consumers were then qualitatively compared and the main gaps identified. The results revealed that Swiss consumers had several misconceptions regarding the sources and transmission of AMR, and that they in particular underestimated the importance of poultry meat and pets as a potential source of AMR. Furthermore, high uncertainty was noted in experts regarding the prevalence of AMR in pets and the potential of transmission to their owners. Consequently, awareness of AMR transmission pathways should be increased among consumers to overcome common misconceptions, which will help reduce the risk of transmission. Further research is needed to better understand the pets' potential to harbor and transmit AMR to their owners, and to identify most effective methods to increase risk awareness in consumers as well as intervention strategies promoting consumer behaviors to mitigate AMR transmissions at the human-animal interface.