An experimental model for studying claw lesions in growing female pigs

Problems with claw lesions leading to lameness are a growing concern in pig production. However, the causes and development of claw lesions are poorly understood and studies on prevention of claw lesion problems in gifts and sows are limited.This study tested a new experimental model which facilitates evaluation of the impact of different risk factors on pig feet lesions.The model consisted of using young gilts with a well-known background and promoting traumatic claw lesions for study purposes by increasing social and agonistic activity through regrouping on concrete flooring. Then claw lesions were assessed systematically and objectively on feet after slaughter. To test the model, two levels of exposure to concrete flooring were compared; normal activity in groups of gifts (no regrouping=NR) and increased activity in groups of gifts by performing several regroupings (repeated regrouping=RR).A total of 72 gilts (pairs of litter mates) in two batches, aged 4 months, were randomly distributed to the two treatments (NR and RR) in group pens (3 gilts per pen) with concrete flooring. The gilts were given approximately 200 g of straw per gilt every day. At 8, 9 and 10 months of age, half the gilts (36 animals) were regrouped with each other. At 11 months of age, all gifts in both treatments were slaughtered and the left rear foot from each was removed and collected for detailed studies of claw lesions. Lesions of the heel, transition heel/toe, white line, wall and toe and over-growth of the heel were assessed on the outer and inner digit. Blind scoring of claw lesions on a scale from 0 to 3 was carried out in laboratory conditions on cleaned claws. Body lesions were also blind-scored on a scale from 0 to 3 one week after the third regrouping.The results showed claw lesions on the soft and hard horn of the claws and significantly (p = 0.004) higher claw lesion score in RR gifts (0.40) than in NR gilts (0.23).It was concluded that as expected, regrouping gifts on concrete flooring resulted in both more numerous and more severe claw lesions than ungrouped gilts. Likewise, body lesion score was significantly (p < 0.001) higher in RR gilts (1.71) than NR gilts (0.46).It was also concluded that the proposed model could be a successful experimental design for challenging different risk factors, e.g. flooring and management, for development of claw lesions in pigs. (C) 2015 Elsevier B.V. All rights reserved

Prevalence of lameness and claw lesions during different stages in the reproductive cycle of sows and the impact on reproduction results

Lameness in sows is an emerging disease condition with major effects on animal welfare and economics. Yet the direct impact on reproduction results remains unclear. The present field study investigated the impact of lameness and claw lesions throughout the reproductive cycle on (re)production results of sows. In five farms, a total of 491 group-housed sows were followed up for a period of one reproductive cycle. Sows were assessed for lameness every time they were moved to another area in the farm. Claw lesions were scored at the beginning and at the end of the cycle. Reproduction results included the number of live-born piglets, stillborn piglets, mummified fetuses and crushed piglets, weaning-to-oestrus interval and the presence of sows not showing oestrus post weaning, returning to service and aborting. Sows that left the group were recorded and the reason was noted. A mean prevalence of lameness of 5.9% was found, although it depended on the time in the productive cycle. The highest percentage of lame sows (8.1%) was found when sows were moved from the post-weaning to the gestation stable. No significant associations were found between lameness and reproduction parameters with the exception of the effect on mummified foetuses. Wall cracks, white line lesions, heel lesions and skin lesions did have an effect on farrowing performance. Of all sows, 22% left the group throughout the study, and almost half of these sows were removed from the farm. Lameness was the second most important reason for culling. Sows culled because of lameness were significantly younger compared with sows culled for other reasons (parity: 2.6 +/- 1.3 v. 4.0 +/- 1.8). In conclusion, the present results indicate that lameness mainly affects farm productivity indirectly through its effect on sow longevity whereas claw lesions directly affect some reproductive parameters. The high percentage of lame sows in the insemination stable indicate that risk factor studies should not only focus on the gestation stable, but also on housing conditions in the insemination stable

Locomotion disorders and skin and claw lesions in gestating sows housed in dynamic versus static groups

Lameness and lesions to the skin and claws of sows in group housing are commonly occurring indicators of reduced welfare. Typically, these problems are more common in group housing than in individual housing systems. Group management type (dynamic versus static) and stage of gestation influence the behavior of the animals, which in turn influences the occurrence of these problems. The present study compared prevalence, incidence and mean scores of lameness and skin and claw lesions in static versus dynamic group housed sows at different stages of gestation during three consecutive reproductive cycles. A total of 10 Belgian sow herds were monitored; 5 in which dynamic groups and 5 in which static groups were utilized. All sows were visually assessed for lameness and skin lesions three times per cycle and the claws of the hind limbs were assessed once per cycle. Lameness and claw lesions were assessed using visual analogue scales. Static groups, in comparison with dynamic groups, demonstrated lower lameness scores (P<0.05) and decreased skin lesion prevalence (24.9 vs. 47.3%, P<0.05) at the end of gestation. There was no difference between treatment group regarding claw lesion prevalence with 75.5% of sows demonstrating claw lesions regardless of group management. Prevalences of lameness (22.4 vs. 8.9%, P<0.05) and skin lesions (46.6 vs. 4.4%, P<0.05) were highest during the group-housed phase compared to the individually housed phases. Although the prevalence of lameness and skin lesions did not differ three days after grouping versus at the end of the group-housing phase, their incidence peaked during the first three days after moving from the insemination stalls to the group. In conclusion, the first three days after grouping was the most risky period for lameness incidence, but there was no significant difference between static or dynamic group management

Impact of group housing of pregnant sows on health

Group housing of sows during gestation is mandatory in the EU since 2013. Compared to housing in individual crates, group housing allows the animals to express normal activity and behavior. The present paper discusses the impact of group housing on health, with emphasis on lameness, aggression and possible spread of infectious diseases. The prevalence of lameness is generally higher in sows housed in group than in sows housed individually. Floor space per sow, group size, pen design and flooring are the main factors of group housing involved in lameness development. Especially floor characteristics are important, and particular attention should be paid to the type, building material and quality of the floor, hygiene and the use of bedding such as straw or rubber mats. Aggression between sows is another critical issue in group housing systems. It occurs predominantly because of competition for access to a limited resource, or to establish a social hierarchy. Key factors to prevent aggression in group housing include gradual familiarization of unfamiliar animals, sufficient space and pen structure during initial mixing, minimizing opportunities for dominant sows to steal food from subordinates, provision of a good quality floor, environmental enrichment and use of straw bedding. Very scarce evidence-based information is available on the relationship between group housing and infectious disease. Compared to individual housing, sows in group housing have more nose-to-nose contact, and they have more oral contact with feces and urine. These factors could contribute to a higher or faster transmission of pathogens, but so far, there is no evidence showing more disease problems in group housing systems. In conclusion, in group housing systems, particular attention should be paid to prevention of lameness and aggression. Management is crucial but also feeding strategies, floor and bedding, and design of housing are very important as relatively minor adjustments may exert major effects on the animals.Peer reviewe

Aksjeklasser. Begrensninger i bruken i norsk og europeisk regelverk

Oppgavens tema er aksjeklasser i norsk rett og lovreguleringen av dette. Oppgaven analyserer også reguleringen av aksjeklasser i EU og konsekvensene for norsk selskapsrett. Problemstillingen for oppgaven er hvilke begrensninger som gjelder for aksjeselskapers bruk av aksjeklasser i norsk rett, bakgrunnen for disse begrensningene og konsekvensene av dem. I tillegg inneholder oppgaven en kvantitativ undersøkelse av hvilke selskaper i Norge som benytter seg av aksjeklasser, en nærmere utredning av hvilke rettigheter og plikter som reguleres ved bruk av aksjeklasser og hva slags aksjeklasser som benytter seg av denne muligheten

Knowledge flows through patent collaborations: The effect of regional trade agreements. An empirical approach

This thesis analyzes the effect of regional trade agreements (RTAs) on international patent collaborations, as a measure of knowledge flows. Patent collaboration generate knowledge flows between inventors through interactions and learning opportunities. By the use of the European Patent Office’s Patstat database on patent applications and the gravity dataset from the french research institute CEPII, I estimate the effect of RTAs on international patent collaboration between inventors. The panel consists of 209 countries over the time period 1965 - 2006. The amount of patent collaboration between inventors residing in different countries will be estimated using the gravity model, which is a highly successful empirical model. Within my work, I extend the gravity equation with the outcome of international patent collaborations, as a measure of knowledge flow. Furthermore, I estimate this equation using OLS and Poisson regressions with country- year specific fixed effects. To secure robustness, I use different estimation methods and subsamples of the data. I also investigate the effect of high- and low- income countries as well as the North American Free Trade Agreement (NAFTA) on international patent collaboration. From this, my findings suggest, positive, significant and robust effect of RTA on knowledge flow, measured by international patent collaboration. In particular, I find that joining a RTA increase international patent collaboration by 55%. Patent collaboration is also positively affected by the presence of a common language, a common border, colonial link and a common legal origin. While being negatively affected by distance. Additionally, I find that the effects are larger when RTAs include stronger rules for intellectual property rights. In total, the estimated effects on international patent collaborations are similar to the effects characterizing international trade, within the gravity framework

Hedgingeffektivitet i valutamarkedet : fleksibilitet eller linearitet?

Gjennom empiriske analyser fra perioden februar 1999 til desember 2015 sammenlikner vi hedgingeffektiviteten for termin- og opsjonsstrategier i valutaparene USDNOK og EURNOK. Opsjonsstrategiene inkludert i studiet er basert på kombinasjoner av call- og putopsjoner, hvor kvoterte 10- og 25-delta Risk-Reversal og Butterfly benyttes i utledningen av implisitt volatilitet for tilhørende delta. Dette studiet tar et noe alternativt utgangspunkt i forhold til store deler tidligere empirisk forskning; i tillegg til å analysere strategienes evne til å redusere ugunstige kursbevegelser, evalueres også nedsiderisikoen involvert fra de respektive hedgingstrategier. Definerte nedsiderisiko kvantifiseres gjennom nedre andre partielle moment (LPM2) og CVaR, ettersom tydelig asymmetri og ikke-normalitet i avkastningene observeres. Vi har analysert hvorvidt opsjonsstrategienes mulighet for delvis deltakelse i gunstige kursbevegelser kompenserer for antatt dårligere reduksjon av ugunstige spotfluktuasjoner. Gjennom alle delperiodene finner vi at opsjonsstrategier utelukkende oppnår høyere hedgingeffektivitet enn terminer, hvilket kan tolkes som at over tid kompenserer opsjonsstrategienes større fleksibilitet for svakere evne til å redusere ugunstige kursbevegelser. Terminkontrakten viser seg likevel å være den mest effektive hedgingstrategien mot appresiering i spotkurs, men hvor den økte nedsiderisikoen medfører at totale kostnadsbesparelser sjeldent tydelig overgår hva oppnådd ved opsjoner. Spesielt observeres 25-delta strategier over tid å generere høyest hedgingeffektivitet, tross perioder hvor volatilitetsoverflaten har vist seg å være markant skjevfordelt