Simulation models are suitable to investigate how complex systems respond to changes. This is of particular interest regarding animal feed efficiency as this trait must be evaluated throughout the entire lifetime and thus is affected by trade-offs between physiological functions. The aim was to extend and calibrate the dynamic, mechanistic simulation model “Acquisition and Allocation” (AQAL) from dairy cows to reproductive ewes. This model was originally developed for investigating the effects of resource acquisition and allocation potentials on feed efficiency but also allows investigation of trade-offs between life functions. The model represents an individual female from birth to death or herd exit and uses four input parameters to describe the resource acquisition ability and allocation potential. The obtained energy is split between life functions such as maintenance, growth, reproduction and lactation. By including reproductive management rules, it allows for shifts between physiological stages, which then feedback and affect the current acquisition ability and resource allocation. To adapt the model to a reproductive ewe, we have included a litter size effect, an acquisition capacity linked to gestation, and a seasonal conception probability. The litter size is influenced by the proportion of fat in empty body weight at conception, and it affects the acquisition linked to gestation, the allocation to gestation and the allocation to lactation. We also incorporated the energetic costs of the gravid uterus depending on litter size. We use three different acquisition-allocation profiles to test the consistency of the litter size effect. We show that the model simulates consistent lifetime trajectories of reproductive ewes and that the effect of litter size adequately reflects the demands of increased litter size within the different acquisition/allocation profiles.
Following EU's decision to ban neonics, several alternative solutions have emerged from the dedicated Frenchnational research program initiated in 2020. Companion plants, such as barley or oats, sown at the same timeas beets, proved to have a repellent effect and reduce aphids' presence in sugar beet fields. This paper evaluatesthe economic viability of this particular solution and assesses how it reduces the risk of sugar beet infectionsby virus yellows. We show that although companion plants may be effective in repelling aphids, the stricteconomic impact associated with the reduction of aphids' population is mainly negative under cost-benefitassumptions currently adopted. Our analysis is based on the incidence model developed by Qi et al. It factorsin costs induced by the planting and destruction of companion plants at a [4-6] leaf stage and factors in a"competition" effect between companion plants and beets. As a consequence of our analysis, we highlight theneed to run further research work in two directions, (1) analyze the potential of additional benefits offeredby the solution to complement its strict impact on the number of aphids in sugar beet fields and (2) analyzepotential benefits offered by synergies and combinations of companion plants with other viable solutions usedto mitigate the spread of virus yellows in sugar beets.
To increase lifetime production of ewes, it has been suggested to mate ewe lambs. However, research on the effect of age at first lambing on longevity has shown conflicting results. This study investigated the impact of early life reproduction (i.e., the effect of age at first lambing and litter size) and environmental conditions on longevity in a prolific sheep breed traditionally bred as lambs. Lifetime performance data were obtained from 550 884 Norwegian White Sheep born between 2000 and 2013 spread across Norway. All ewes lambed their first litter either as 1-year-old or 2-year-olds. Longevity was investigated using a linear mixed model with age at first lambing, litter size, county, the covariates early- and late parturition, and two categorical variables describing cross-fostering and success in weaning as fixed effects. Herd x year was fitted as a random effect. The lifespan of the ewes was affected both by age of the ewe at first reproduction and the reproductive investment (i.e., litter size). The predicted lifespan for ewes mated as lambs was 1 548 days (4.2 years) whereas the lifespan for those mated as 2-year-olds was 1 700 days (4.7 years). There was a curvilinear relationship between lifespan and litter size. Lifespan increased from 1 272 days (3.5 years) to 1 618 days (4.4 years) when litter size increased from 0 to 1 lamb. Further increased reproductive investment resulted in a decreased lifespan with a litter size of 4 having the shortest lifespan of 1 468 days (4.0 years). The relation between litter size and lifespan was similar but at different levels for both age groups of ewes, except for ewes rearing less lambs than they gave birth to. In that group, ewes mated as lambs had a peak predicted lifespan at 1 504 days (4.1 years) with a litter size of one lamb, whereas those first mated as 2-year-olds had their peak predicted lifespan of 1 650 days (4.5 years) with a litter size of two lambs. The relationship between longevity and reproductive investment was in some cases affected by environmental conditions. However, the effect was not consistent with latitude. In conclusion, ewes mated as lambs, in general, live shorter lives compared to those first mated as 2-year-olds but environmental importance for longevity and reproduction needs further investigation.
French legislation requires large and medium-sized hospitals to publicly report their greenhouse gas (GHG) emissions. Yet, many hospitals fail to comply with this regulation, while others report voluntarily. The organizational drivers behind this behavior remain underexplored. This study examines whether hospitals disclose their GHG emissions as part of a broader strategy to differentiate themselves-similar to how they report patient satisfaction scores to signal quality. We explore whether carbon reporting is used as a vertical differentiation strategy in the French healthcare system. We used a mixed-methods approach. First, we analyzed national administrative data to test whether reporting GHG emissions is associated with reporting patient satisfaction scores. Second, we conducted semi-structured interviews with hospital managers to understand the motivations behind emissions reporting. Quantitatively, we found no significant association between the two types of reporting. Hospitals do not appear to use GHG emissions disclosure and patient satisfaction scores as part of the same signaling strategy. Qualitative findings confirmed that GHG reporting is primarily driven by internal factors such as executive leadership, process improvement, and organizational values, rather than external differentiation or patient demand. Carbon reporting in French hospitals is not currently used as a differentiation strategy. Stronger regulatory enforcement is needed to ensure compliance. In addition, hospitals require support-through methodological guidance, training, and the development of dedicated sustainability roles-to integrate environmental performance into their management systems and contribute meaningfully to healthcare decarbonization.
Fish spawning phenology is a major concern for conservation and fisheries management. New intensive data sources such as GPS-based tracking data or high resolution catch declaration data are progressively becoming available in the field of marine ecology. These benefit from high spatio-temporal resolution and open new research avenues to investigate inter-annual and seasonal variability of phenology. In this paper, we illustrate how catch declarations modeling coupled with spatio-temporal dimension reduction methods known as Empirical Orthogonal Functions (EOF) can be used to synthetize spatio-temporal signals in fish distribution; Specifically, we address the following questions; (1) can we identify spatio-seasonal patterns that can be interpreted in terms of seasonal migration between essential habitats? (2) can we identify changes in the phenology? (3) are those changes related to environmental drivers? The analysis is illustrated through the analysis of the reproduction phenology on three key commercial species in the Bay of Biscay (Hake, Sole and Sea Bass). The EOF analysis on these species emphasizes strong seasonal spatio-temporal patterns that correspond to migration patterns between feeding areas and reproduction areas. Based on this methodology, we identify seasonal variations in the timing of the reproduction and we relate these to Sea Surface Temperature, a key driver of fish reproduction.
