Hypomagnesemi som riskfaktor för kalvningsförlamning hos mjölkkor

I sen dräktighet och vid laktationens inledning avger mjölkkor stora mängder kalcium till fostret och mjölkproduktionen. Kons förmåga att upprätthålla kalciumbalansen sker med hjälp av mobilisering av kalcium från skelettet samt upptag av kalcium från tarmen, mekanismer som regleras hormonellt, huvudsakligen av parathormon (PTH) och 1,25-dihydroxyvitamin D3 (calcitriol). Om kons regleringsmekanismer inte lyckas återställa kalciumkoncentrationen i plasma drabbas djuret av klinisk hypokalcemi som kan orsaka kalvningsförlamning. Flera olika strategier har etablerats för att förebygga denna utveckling. En väletablerad metod är lågkalciumdieten som syftar till att stimulera djurets metabolism för att öka aktiveringen av de endogena regleringsmekanismerna vilket resulterar i en bättre förmåga hos djuret att återställa kalciumförlusterna. En annan metod är modifiering av dietary cation anion difference (DCAD) vars syfte är öka effekten av PTH på dess målvävnader. Syftet med denna litteraturöversikt var att undersöka huruvida låga magnesiumnivåer hos mjölkkor ökar risken att de drabbas av kalvningsförlamning. Brist på magnesium har visats reducera utsöndringen av PTH till blodet samt minska hormonets förmåga att stimulera sina receptorer i skelett och njurar. Båda dessa faktorer reducerar aktiveringen av vitamin D till calcitriol vilket minskar kalciumabsorptionen i tarmen och ytterligare hämmar förmågan till benresorption. Resultatet av dessa förändringar i regleringsmekanismerna hos hypomagnesemiska kor är att förmågan att kompensera kalciumförluster vid kalvning är kraftigt nedsatt. Detta stöds också av ett flertal analyser där minskade nivåer av magnesium i utfodringen visar starkt samband med incidensen av kalvningsförlamning. Plasmanivåerna av magnesium är framförallt beroende av ett kontinuerligt upptag från fodret. Mobilisering från kroppens reserver har inte en tillräcklig förmåga att motverka en snabbt uppstående hypomagnesemi. Slutsatsen är att ett tillräckligt magnesiumintag är av yttersta betydelse för att undvika klinisk hypokalcemi. Rekommendationerna för magnesiumutfodring till sinkor är eventuellt för låga och skulle sannolikt kunna höjas då biverkningar av excessivt intag är relativt lindriga.During the late stages of gestation and at the onset of lactation dairy cows convey large amounts of calcium to the fetus and the production of milk. The ability of the cow to restore calcium levels in plasma is dependent on mobilisation of calcium from the skeleton and uptake of calcium from the small intestine, mechanisms which are regulated by hormones, chiefly by parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D3 (calcitriol). If the regulating mechanisms are unable to counteract the drop in plasma levels of calcium the animal becomes hypocalcemic which may result in periparturient paresis. Several different strategies have been established to prevent this condition. The low calcium diet aims to stimulate the metabolism of the animal in order to increase activation of the endogenous regulating mechanisms which results in a better ability to counteract the losses of calcium. Another method is modification of dietary cation anion difference (DCAD) in order to increase the effect of PTH on its target tissues. The aim of this thesis is to investigate whether low magnesium levels in dairy cattle increases the risk of periparturient paresis. Many studies have shown that magnesium balance is an important factor in development of periparturient paresis. Magnesium deficiency reduces secretion of PTH from the parathyroid glands as well as decreases the ability of the hormone to stimulate its receptors in the skeleton and kidneys. Both of these mechanisms reduces the synthesis of calcitriol which decreases absorption of calcium in the small intestine and further reduces mobilisation of calcium from bone tissue. The result of these changes in the regulating systems is that the ability of the cow to counterbalance periparturient losses of calcium is greatly hampered. These results are being supported by several studies where decreased levels of magnesium in the diet have been shown to have a strong impact on the incidence of periparturient paresis. Plasma levels of magnesium are primarily dependent upon a continuous uptake of magnesium from the diet. Mobilisation of body stores is not rapid enough to counter a sudden hypomagnesemia. The conclusion is that an adequate magnesum intake is of critical importance in order to avoid clinical hypocalcemia. The recommended magnesium intake for dry cows may be too low and could be increased since side effects of excessive magnesium intake are relatively mild

Mjölkningsrutiner i svenska mjölkkobesättningar med mjölkgrop

Goda mjölkningsrutiner är en viktig del av mjölkningsproceduren när mjölk skall utvinnas från nötkreatur. Genom att använda korrekta rutiner kan man förebygga smittsamma juverinflammationer och möjliggöra effektivt mjölknedsläpp genom taktil stimulering innan mjölkningsorganet appliceras. I flera länder har studier under senare år visat att befintliga rekommendationer för mjölkningsrutiner i stor utsträckning inte följs men få studier har undersökt hur väl de svenska rekommendationerna efterlevs. Huvudsyftena med studien var att undersöka vilka mjölkningsrutiner som används i svenska mjölkkobesättningar med lösdrift och mjölkgrop, hur väl befintliga mjölkningsrekommendationer följs samt att utvärdera om det finns behov av informationsaktiviteter för att öka medvetenheten hos mjölkproducenter om betydelsen av goda mjölkningsrutiner. Denna studie har även analyserat samband mellan efterföljsamhet av rekommenderade mjölkningsrutiner och mjölkavkastning samt beräknat tankcelltal i de besättningar som ingick i studien. Ett delmål var också att undersöka den vetenskapliga evidensen bakom de svenska rekommendationerna. En morgon-, middag- eller eftermiddagsmjölkning observerades i 98 lösdriftsbesättningar med mjölkgrop anslutna till Kokontrollen under 2014-2015. Besättningarna hade 50-210 kor och låg i Götaland och Svealand. Information om mjölkningsrutiner registrerades genom observation samt genom frågor ställda till lantbrukare eller besättningens personal. Årsdata för mjölkavkastning och beräknat tankcelltal inhämtades för varje besättning från Kokontrollen och den rapport från "Signaler Djurvälfärd” som låg närmast i tid intill besöket. Samband mellan mjölkningsrutiner och mjölkavkastning samt beräknat tankcelltal undersöktes med lämpliga statistiska metoder. Studiens resultat visar att svenska rekommendationer för mjölkningsrutiner till stor del inte följs. Många besättningar utför delar av de rekommenderade rutinerna men vissa rutiner används i mycket låg utsträckning. Torr avtorkning av spenarna efter rengöring och användning av mjölkningshandskar bedömdes som de två områden där ökad efterföljsamhet skulle vara av störst betydelse. Besättningar som använde spendopp/spenspray efter mjölkning hade signifikant lägre beräknat tankcelltal samt signifikant högre mjölkavkastning än besättningar som ej använde spendopp/spenspray. En signifikant högre mjölkavkastning sågs i besättningar där spendopp användes jämfört med besättningar där spenspray användes. Eftersom både mjölkavkastning och tankcelltal kan påverkas av faktorer som ej utvärderats i denna studie bör resultaten tolkas med försiktighet. Tankcelltal bedöms dock som en bättre indikator för goda mjölkningsrutiner än mjölkavkastning. De svenska rekommendationerna för mjölkningsrutiner är generellt välgrundade enligt den litteraturöversikt som genomförts i denna studie. Sammanfattningsvis brister efterföljsamheten av de svenska rekommendationerna för mjölkningsrutiner och ett stort behov finns av informationsaktiviteter för att öka användningen av de rekommenderade rutinerna.Good milking routines are an important part of the milking process when milk is obtained from dairy cattle. By using correct routines infectious mastitis can be pre-empted and an efficient milk let down can be obtained by tactile stimulation before the milking unit is applied. During recent years studies made in several countries have highlighted that existing recommendations for milking routines are often not adhered to but few studies have investigated the compliance with the Swedish recommendations. The main aims of this study were to investigate which milking routines that are used in Swedish freestall dairy farms with milking parlour, the level of compliance with existing milking recommendations and to assess if there is a need for information activities to increase the knowledge of dairy farmers about the importance of good milking routines. This study has also analysed associations between compliance with recommended milking routines and milk yield and milk somatic cell count (SCC) at farm level in the farms participating in the study. An additional aim was to investigate the scientific evidence supporting the the Swedish recommendations. One morning, mid day or evening milking was observed in 98 freestall dairy farms with milking parlour affiliated with Kokontrollen (a Swedish programme for milk production) during 2014- 2015. The dairy farms had 50-210 cows and were situated in Götaland and Svealand. Information concerning milking routines were registered by observation and through questions asked to the farmer or farm staff. Annual statistics for milk yield and SCC were obtained in the report from Kokontrollen which was chronologically most adjacent to the visit on the farm. Associations between milking routines and milk yield or SCC were investigated using suitable statistical methods. The results of the study show that Swedish recommendations for milking routines are, in many aspects, not adhered to. Many farms use some of the recommended routines but certain routines are used to a very small extent. Manual drying of the teats after teat cleaning and use of milking gloves were deemed to be the areas where an increased compliance would be of most importance. Farms using postmilking teat dip or teat spray had significantly lower SCC and significantly higher milk yield than farms not using teat dip or teat spray. A significantly higher milk yield was seen in farms using teat dip compared to farms using teat spray. Since both milk yield and SCC are influenced by several factors that were not included in this study, the results obtained should be treated with care. SCC however was deemed a more reliable indicator for good milking routines compared to milk yield. The Swedish recommendations for milking routines are generally well founded according to the literature review performed in this study. In summary, compliance with the Swedish recommendations for milking routines is lacking and there is a great need for information activities in order to increase the use of the recommended routines

Coupled diffusion-deformation multiphase field model for elastoplastic materials applied to the growth of Cu6Sn5

A coupled diffusion-deformation, multiphase field model for elastoplastic materials is presented. The equations governing the evolution of the phase fields and the molar concentration field are derived in a thermodynamically consistent way using microforce balance laws. As an example of its capabilities, the model is used to study the growth of the intermetallic compound (IMC) Cu6Sn5 during room-temperature aging. This IMC is of great importance in, e.g., soldering of electronic components. The model accounts for grain boundary diffusion between IMC grains and plastic deformation of the microstructure. A plasticity model with hardening, based on an evolving dislocation density, is used for the Cu and Sn phases. Results from the numerical simulations suggest that the thickness of the IMC layer increases linearly with time and that the morphology of the IMC gradually changes from scallop-like to planar, consistent with previous experimental findings. The model predicts that plastic deformation occurs in both the Cu and the Sn layers. Furthermore, the mean value of the biaxial stress in the Sn layer is found to saturate at a level of −8 MPa to −10 MPa during aging. This is in good agreement with experimental data

Creating dynamic groups using context-awareness

This article presents the conceptual communication model of dynamic groups, that dynamically utilizes three traditional communication metaphors through the use of context-based information. Dynamic groups makes creation, management and usage of groups easy. It enables social network structures to be maintained in both virtual and face-to-face settings as well as in the combination thereof. This article defines the dynamic management of advanced contact lists which can include presence and status information, a/synchronous multimedia communication tools, and methods for structuring social networks. It also contains an initial evaluation and a proposed architecture for technical realisation.Godkänd; 2007; 20071130 (miabac

Creating digital life stories through activity recognition with image filtering

Abstract. This paper presents two algorithms that enables the MemoryLane system to support persons with mild dementia through creation of digital life stories. The MemoryLane system consists of a Logging Kit that captures context and image data, and a Review Client that recognizes activities and enables review of the captured data. The image filtering algorithm is based on image characteristics such as brightness, blurriness and similarity, and is a central component of the Logging Kit. The activity recognition algorithm is based on the captured contextual data together with concepts of persons and places. The initial results indicate that the MemoryLane system is technically feasible and that activity-based creation of digital life stories for persons with mild dementia is possible

Nutritional Status of Flemish Vegetarians Compared with Non-Vegetarians: A Matched Samples Study

The present study compares the nutritional status of vegetarian (V) with non-vegetarian (NV) subjects. A three-day food record and a health questionnaire were completed by 106 V and 106 NV matched for following characteristics: sex, age, BMI, physical activity, tobacco use and alcohol consumption. Total energy intake was not significantly different (men: V: 2,346 ± 685 kcal/d; NV: 2,628 ± 632 kcal/d; p = 0.078; women: V: 1,991 ± 539 kcal/d; NV: 1,973 ± 592 kcal/d; p = 0.849). Macronutrients intake differed significantly between the V and NV subjects for protein (men: V:12.7 ± 2.3 E%; NV:15.3 ± 4.5 E%; p = 0.003; women: V: 13.2 ± 2.3 E%; NV:16.0 ± 4.0 E%; p < 0.001), fat (men: V: 29.3 ± 8.4 E%; NV: 33.8 ± 5.3 E%; p = 0.010; women: V: 29.7 ± 6.9 E%; NV: 34.7 ± 9.0 E%; p < 0.001), and carbohydrate (men: V: 55.3 ± 10.1 E%; NV: 47.4 ± 6.9 E%; p < 0.001; women: V: 55.1 ± 7.6 E%; NV: 47.2 ± 8.2 E%; p < 0.001). The intake of most minerals was significantly different between the V and the NV subjects. V had a lower sodium intake, higher calcium, zinc, and iron intake compared to the NV subjects. Our results clearly indicate that a vegetarian diet can be adequate to sustain the nutritional demands to at least the same degree as that of omnivores. The intakes of the V subjects were closer to the recommendations for a healthy diet when compared to a group of well matched NV subjects

Evidence of 3D strain gradients associated with tin whisker growth

We have used Differential Aperture X-ray Microscopy (DAXM) to measure grain orientations and deviatoric elastic strains in 3D around a tin whisker. The results show strain gradients through the depth of the tin coating, revealing a higher strain deeper in the Sn layer. These higher strains are explained by the volume change occurring during growth of the intermetallic phase Cu6Sn5 at the interface between the Cu substrate and the Sn coating and at grain boundaries between Sn grains

Cross-cutting principles for planetary health education

Since the 2015 launch of the Rockefeller Foundation Lancet Commission on planetary health,1 an enormous groundswell of interest in planetary health education has emerged across many disciplines, institutions, and geographical regions. Advancing these global efforts in planetary health education will equip the next generation of scholars to address crucial questions in this emerging field and support the development of a community of practice. To provide a foundation for the growing interest and efforts in this field, the Planetary Health Alliance has facilitated the first attempt to create a set of principles for planetary health education that intersect education at all levels, across all scales, and in all regions of the world—ie, a set of cross-cutting principles

Genomic analyses identify hundreds of variants associated with age at menarche and support a role for puberty timing in cancer risk

The timing of puberty is a highly polygenic childhood trait that is epidemiologically associated with various adult diseases. Using 1000 Genomes Project-imputed genotype data in up to similar to 370,000 women, we identify 389 independent signals (P <5 x 10(-8)) for age at menarche, a milestone in female pubertal development. In Icelandic data, these signals explain similar to 7.4% of the population variance in age at menarche, corresponding to similar to 25% of the estimated heritability. We implicate similar to 250 genes via coding variation or associated expression, demonstrating significant enrichment in neural tissues. Rare variants near the imprinted genes MKRN3 and DLK1 were identified, exhibiting large effects when paternally inherited. Mendelian randomization analyses suggest causal inverse associations, independent of body mass index (BMI), between puberty timing and risks for breast and endometrial cancers in women and prostate cancer in men. In aggregate, our findings highlight the complexity of the genetic regulation of puberty timing and support causal links with cancer susceptibility