Tail biting in pigs: is it possible to rear the heavy pig avoiding tail docking?

Tail biting in pigs has been identified as a behavioural problem for decades. It has serious consequences for animal welfare and for the income of the farmers The inability to prevent occurrence of this adverse behavior under commercial farm conditions has resulted in the majority of pig producers considering necessary to dock the tails of all piglets as a preventative measure. This management choice, represents both an animal welfare and an ethical issue, as highlighted in the EU Directive 2008/120 on pig welfare which constrains routine tail docking and emphasizes the need to find alternative preventative strategies. Tail biting prevalence studies have been conducted in most of the UE Countries, but cross-study comparisons appear difficult for the different populations considered. Moreover, most of the data did not concern heavy pig production, with a lack of a complete description of the problem in a prolonged rearing context. The first step of this thesis was to identify the real prevalence of tail biting in Italy, completing an European picture. Moreover, an epidemiological approach was adopted in order to identify the management and housing factors influencing tail biting in the specific heavy pig rearing context. The study highlighted a low incidence of lesions in Italy (0.15% of affected animals on a sample of 79,780 animals). This could be related to the great percentage, (close to 100%), of docked pigs, but at the same time suggested that rearing heavy pigs in a prolonged fattening cycle does not seems to worsen the risk of tail biting. Furthermore, were identified several risk factors for tail biting on heavy pig commercial farms. Results could be relevant to the pig industry in order to reduce the economical losses due to tail biting, giving emphasis to the respect of animal welfare legislation regarding space allowance, the availability of adequate environmental enrichment and environmental parameters such as ammonia concentration and temperature. Once a causal risk factor has been demonstrated on farm, measures should be taken to minimize the incidence of tail biting, thereby enhancing animal welfare. A second step was to evaluate the welfare of undocked pigs in the specific heavy pig rearing context, investigating the feasibility to avoid tail docking in a prolonged fattening phase. Gender and the presence of straw were also considered in their effect on tail biting by evaluating welfare indicators such as blood parameters, culling rate, behavior, and lesions at ears and tail. Further investigations were conducted on mortality rate, causes of death, and the presence of lung lesions and oesophago -gastric ulcer (OGU) at slaughter. The outcome of the study suggests that the combined use of solid floors, compliance with the parameters established by EU legislation on the protections of pigs in terms of space allowance, environment parameters, and presence of chains and sawdust as enrichments seems to allow the fattening of heavy pigs without performing tail docking with no outbreak of injurious tail biting. Straw therefore seems to be an important tool in both increasing explorative behavior and preventing biting and lesions, particularly in the early stage of fattening. Furthermore, results at slaughter reveal the beneficial effects of straw on the susceptibility to gastric ulcer in the heavy pigs production system, for which very few data are available on this topic. The straw was beneficial, despite the fact that only a relatively small quantity was provided to pigs, allowing management problems due to slurry outflow obstruction or excessive farmer workload to be avoided. In a further field study, tail biting was evaluated throughout a entire producing cycle of heavy pigs, starting from weaning to slaughter. The aim was to investigate welfare and tail biting outbreaks also in the weaning phase, having available data of individually marked animals during their whole growth. Slatted floor was chosen as the most common floor type used in the heavy pig production, but even recognized as one of the mayor risk factors for tail biting. The outcome of the weaning phase was that undocked tails could represent an alternative recipient for exploration behavior in weaning pigs, with the consequence of greater incidence of tail lesions. However, seems that the higher level of lesions was related especially to the age. Probably, the social stress related to the progressive reduction of the space allowance due to the increasing size of the growing animals could be a relevant factor in display of tail biting. During the fattening phase, to avoid tail docking in pigs with a prolonged rearing cycle as for the heavy pig production, seems to provoke the rise of tail lesions. However, this finding, with the combined use of slatted floors, compliance with the parameters established by EU legislation in terms of space allowance and environmental parameters, and presence of chains and straw in a rack as enrichments, seems not associated to the variation of blood parameters and behavior, suggesting an insufficient intensity to cause severe welfare problems. Nevertheless, potential economical losses due to the injured tails should be considered even if not accompanied by evident poor welfare

Protocol Parameters and their Inter-Relations in X.25. INWG 96.1 Sample Network Architecture

The purpose of this paper is to have a close look at the class of problems that arise in the interconnection of different computer systems through a packet switching network. The layered protocol's architecture is assumed to separate functionally and to identify the tasks to be performed in the various parts of the network, either in the packet switching subnetwork, or in the end processors. Concepts are then introduced to identify the characteristic parameters of each protocol layer. A further step is carried out by considering a sample architecture built on well-known protocols at different levels, up to the transport level, and developing an analysis of their interaction in order to identify interdependencies and constraint relations on the values of the characteristic parameters

Axion–sterile neutrino dark matter

Extending the standard model with three right-handed neutrinos and a simple QCD axion sector can account for neutrino oscillations, dark matter and baryon asymmetry; at the same time, it solves the strong CP problem, stabilizes the electroweak vacuum and can implement critical Higgs inflation (satisfying all current observational bounds). We perform here a general analysis of dark matter (DM) in such a model, which we call the a nu MSM. Although critical Higgs inflation features a (quasi) inflection point of the inflaton potential, we show that DM cannot receive a contribution from primordial black holes in the a nu MSM. This leads to a multicomponent axion-sterile neutrino DM and allows us to relate the axion parameters, such as the axion decay constant, to the neutrino parameters. We include several DM production mechanisms: the axion production via misalignment and decay of topological defects as well as the sterile neutrino production through the resonant and non-resonant mechanisms and in the recently proposed CPT-symmetric universe