Optimal produktion

Optimal Production in Reindeer Husbandry.There are three ways to optimize the reindeer herd: 1) Adjusting the reindeer number to pasture resources. 2) Keeping as many productive animals in the herd as possible through slaughter. 3) Increasing the herd quality through selection.Renhjorden bör optimeras så att den fungerar som en "skördeapparat" for bete och lämnar största möjliga bidrag till försörjningen för dem som lever av renskötsel. Det finns minst tre sätt att optimera renhjorden, nämligen (1) anpassning av djurantalet till betesresurserna så att djurens kondition och därmed produktiviteten kan bibehållas på hög nivå, (2) utforma renhjordens struktur med hjalp av slaktuttaget så att den innehåller så stor andel produktiva djur som möjligt, och (3) förbättra djurmaterialets produktionsmässiga kvalitet genom urval baserat på registrerad produktion. Betesanpassningen är den mest grundläggande åtgärden och ger den snabbaste effekten. Även hjordstrukturering är en åtgärd som ger relativt snabb effekt och som dessutom kan beslutas och utforas av den enskilde djuraägaren utan att störa den kollektiva renskötseln. Urval är en åtgärd som ger effekt först på längre sikt och därför kräver en konsekvent insats under en längre tid

Renskötselforskning i Sverige

About the reindeer husbandry research in Sweden

Optimal hjordsammansättning - ett systemanalytisk problem

Optimal hjordsammansättning - ett systemanalytisk problem

Traditional ecological knowledge among Sami reindeer herders in northern Sweden about vascular plants grazed by reindeer

Traditional knowledge about how reindeer utilize forage resources was expected to be crucial to reindeer herders. Seventeen Sami reindeer herders in four reindeer herding communities in Sweden (“samebyar” in Swedish) were interviewed about plants species considered to be important reindeer food plants in scientific literature. Among 40 plant species, which the informants were asked to identify and indicate whether and when they were grazed by reindeer, they identified a total of 21 plant taxa and five plant groups. They especially recognised species that were used as human food by the Sami themselves, but certain specific forage plants were also identified. Detailed knowledge of vascular plants at the species level was surprisingly general, which may indicate that knowledge of pasture resources in a detailed species level is not of vital importance. This fact is in sharp contradiction to the detailed knowledge that Sami people express for example about reindeer (as an animal) or snow (as physical element). The plausible explanation is that observations of individual plant species are unnecessarily detailed information in large-scale reindeer pastoralism, because the animals graze freely under loose herding and border surveillance

Sven Skjenneberg Doctor Honoris Causa

In August 28, 1993, Sven Skjenneberg was conferred the degree of Veterinary Medical Doctor Honoris Causa at the Swedish University of Agricultural Sciences, Uppsala, Sweden

Multivariate clustering of reindeer herding districts in Sweden according to range prerequisites for reindeer husbandry

The 51 reindeer herding districts in Sweden vary in productivity and prerequisites for reindeer herding. In this study we characterize and group reindeer herding districts based on relevant factors affecting reindeer productivity, i.e. topography, vegetation, forage value, habitat fragmentation and reachability, as well as season lengths, snow fall, ice-crust probability, and insect harassment, totally quantified in 15 variables. The herding districts were grouped into seven main groups and three single outliers through cluster analyses. The largest group, consisting of 14 herding districts, was further divided into four subgroups. The range properties of herding districts and groups of districts were characterized through principal component analyses. By comparisons of the suggested grouping of herding districts with existing administrative divisions, these appeared not to coincide. A new division of herding districts into six administrative sets of districts was suggested in order to improve administrative planning and management of the reindeer herding industry. The results also give possibilities for projections of alterations caused by an upcoming global climate change. Large scale investigations using geographical information systems (GIS) and meteorological data would be helpful for administrative purposes, both nationally and internationally, as science-based decision tools in legislative, economical, ecological and structural assessments. Abstract in Swedish / Sammanfattning: Multivariat gruppering av svenska samebyar baserat på renbetesmarkernas grundförutsettningar Svenska renskötselområdet består av 51 samebyar som varierar i produktivitet och förutsättningar för renskötsel. Vi analyserade variationen mellan samebyar med avseende på 15 variabler som beskriver topografi, vegetation, betesvärde, fragmentering av betesmarker, klimat, skareförekomst och aktivitet av parasiterande insekter och vi föreslår en indelning av samebyar i tio grupper. Den största gruppen, som bestod av 14 samebyar, delades vidare in i 4 undergrupper. Klusteranalyser med 4 olika linkage-varianter användes till att gruppera samebyarna. Principalkomponentsanalys användes för att kartlägga undersökta variabler och de resulterande samebygruppernas karaktär. Samebygrupperna följde inte länsgränser och tre samebyar föll ut som enskilda grupper. Denna undersökning ger underlag för jämförelser mellan samebyar med beaktande av likheter och olikheter i fråga om produktivitet och funktionella särdrag istället för länsgränser och historik. Vi föreslår en ny administrativ indelning i sex områden som skulle kunna fungera som ett alternativt underlag för planering och beslut som rör produktionsaspekter i rennäringen. Resultaten ger också underlag för förutsägelser av förändringar i samebyars produktionsförutsättningar till följd av klimatförändringar

Genetic response to selection on reindeer calf weights

Selection response was investigated after 11 years of selection in the herding district of Ruvhten Sijte in Sweden (63°N,12°E) by comparing the weights of calves owned by herders applying selection with the weights of calves owned by herders not applying selection. Three owner groups in Ruvhten Sijte have selected calves at the autumn slaughter every year since 1986 by retaining heavy calves. They own approximately 45% of the reindeer in Ruvhten Sijte. The other owners do not select on recorded weights, and all animals mix during the mating season. The recorded data on calf weights (1986 to 1997) consisted of 12 484 observations, with mean selection differentials of 2.9 kg and 4.6 kg for female and male calves, respectively (phenotypic standard deviation equal to 4.4 kg). The female generation interval was 6.4 years. In 1996 and 1997, autumn live weights of calves owned by herders applying selection (n = 971) were compared with the weights of calves owned by herders not applying selection (n = 1125). The observed difference was 0.67 kg (total mean = 42.6 kg), of which 0.32 kg was due to differences in dam age structure between the two types of herds, therefore the estimated difference in selection response was 0.35 kg. The realized heritability was 0.2. The potential response that would have been realized if the selected part of the herd had been isolated from gene flow was predicted to be 2.0 kg. In conclusion, the introduction of a selection programme applied by all owners in a herding district would result in an increase in calf weights of approximately 2 kg after two generations of selection.&nbsp

Non-destructive estimation of lichen biomass

Ground lichens constitute a vital part of reindeer winter diet, and non-destructive estimation of lichen biomass is therefore crucial for providing objective data for the management of lichen resources. The aim of this study is to compare precisions of different methods of estimating lichen biomass from ground cover and thallus heights of the four most important lichen species: Cladonia arbuscula, C. rangiferina, C. stellaris, and Cetraria islandica. The methods were validated against actual lichen biomass within 50 cm x 50 cm plots. Different methods gave remarkably similar results, except when cover estimation was based on presence/absence data with a strict criterion of 100% lichen cover. Average thallus heights within the plot explained the variation in lichen biomass as well as lichen volume (estimated from cover and average heights). Relationships between biomass and volume or height were also very similar for all four lichen species, and separation into species thus do not seem necessary for practical purposes.Abstract in Swedish / Sammandrag:Icke-destruktiv skattning av lavbiomassa Marklavar utgör en kritisk del av renars vinterföda, och det blir därmed väsentligt att kunna skatta lavbiomassa på ett icke-destruktivt sätt för att kunna förvalta lavresursen. Syftet med denna studie är att jämföra precisionen hos olika metoder för att skatta lavbiomassa baserat på volym- och bålhöjdsmätningar för de fyra viktigaste arterna: Cladonia arbuscula, C. rangiferina, C. stellaris, and Cetraria islandica. Metoderna validerades mot lavbiomassa mätt i 50 cm x 50 cm provytor. Olika metoder gav anmärkningsvärt lika resultat, förutom när täckning skattades med förekomstdata med ett strikt kriterium av 100% lavförekomst. Medelhöjd på lavbålarna i provytan förklarade lika mycket av variationen i lavbiomassa som lavvolym (baserat på täckning och medelhöjd). Förhållandet mellan biomassa och volym eller bålhöjd var också mycket lika mellan arterna vilket medför att det, för praktiska ändamål, inte är nödvändigt att separera arterna vid skattningar av total biomassa

Relationships between biotic and abiotic range characteristics and productivity of reindeer husbandry in Sweden

Reindeer husbandry is a form of pastoralism where vast areas are used as forage ranges throughout the year. The productivity of the reindeer industry in Sweden is affected by a multitude of factors on different geographical and temporal scales. Our aim was to find combinations of factors characterizing the environmental conditions for reindeer husbandry in the 51 herding districts in Sweden, which correlate strongly with variations in productivity both between herding districts in general and between years within districts. Productivities were described by estimated herd growth rates and carcass condition of slaughtered females and calves. These dependent variables were related to the environmental independent variables using linear regression models and structural equation modelling. The independent variables were either considered as stable (e.g. topography, vegetation and infrastructure) or temporally changing (e.g. season lengths, weather events, disturbances and animal slaughter strategies). The most relevant independent variables were included in a cluster analysis to suggest a grouping of herding districts based on similarities in environmental conditions. Considerably larger variation in productivity was found between herding districts than between years. Different variables were found to be important for between-district and within-district variations, respectively. Season lengths and animal densities were found significant at both levels of variation. Other variables found to be relevant were ruggedness, snow condition, harassing insect activity, supplementary feeding, calf slaughter ratio and previousyear animal condition. Snow precipitation, ice-crust formation and forage quality were presumed to be relevant for reindeer productivity, but were not found to have a large impact on productivity. These factors, however, may have been counteracted by husbandry measures, statistically incorporated in animal density variables, or by being strongly correlated with other, more significant variables. Several of the variables that were found to be important for productivity are correlated with climate and weather and therefore foreseen to be altered in a climatic change perspective. Abstract in Swedish / Sammanfattning: Kopplingar mellan biotiska och geografiska karaktäristika av renskötselområden och renproduktivitet i Sverige Renskötseln i Sverige är en form av pastoralism som använder stora ytor till betesmark. Produktiviteten inom rennäringen i Sverige beror på ett stort antal faktorer som varierar geografiskt och över tid. Undersökningens mål var att hitta kombinationer av faktorer som karaktäriserar förutsättningarna för renskötsel inom de 51 samebyarna i Sverige. Detta genomfördes genom att koppla variationen i renproduktivitet med kombinationer av omgivningsvariabler på sameby- och årsbasis. Produktiviteten definierades genom beräknad hjordtillväxt, slaktkroppskvalitet och vikter på slaktkroppar. Produktivitetsvariablerna relaterades till omgivningsvariablerna genom multipel linjär regression och strukturerad ekvationsmodellering (SEM). Omgivningsvariablerna ansågs för denna undersöknings tidsperspektiv vara antingen stabila (t.ex. topografi, vegetation och infrastrukturer) eller varierande över tid (t.ex. säsongslängder, väderhändelser, störningar och slaktstrategier). De mest relevanta omgivningsvariablerna användes i en klusteranalys för att gruppera samebyarna enligt deras likheter i förutsättningar för renskötsel. Variationen i produktivitet var större mellan samebyar än mellan år inom samebyar. Olika omgivningsvariabler visade sig vara relevanta mellan samebyar och mellan år. Säsongslängd och djurtäthet var relevanta i båda skalorna (mellan samebyar och mellan år), medan faktorer såsom topografisk brutenhet, snöförhållanden, aktivitet av störande insekter, stödutfodring, kalvslaktsandel och kondition på föregående års slaktkroppar var relevanta i en av dem. Snöfall, skarebildning och beteskvalitet antogs vara relevanta men visade sig inte vara signifikant korrelerade med produktiviteten. Dessa faktorer kan dock ha motverkats genom renskötselåtgärder, blivit statistisk inkorporerade i rentäthetsvariabler eller varit korrelerade med andra mer relevanta variabler. Flera av de signifikanta omgivningsvariablerna är väder- och klimatrelaterade, vilka därför antas förändras i den pågående klimatförändringen