SEASONAL VARIATION OF PHENOLS, NITROGEN, FIBER, AND IN VITRO DIGESTIBILITY IN SWEDISH MOOSE

Understanding how different components of food are processed and digested within the compartments of the digestive tract of large herbivores has important implications in their foraging behaviour, nutritional ecology, and techniques for measuring diet composition and nutritional quality of forage. Analysis of contents from different compartments of the digestive tract of moose in central Sweden showed that neutral detergent fiber (NDF) and nitrogen (N) content varied throughout the digestive tract and among individual moose (Alces alces). Total phenols (TP) had an inconsistent pattern throughout the digestive tract, possibly reflecting variation in diet composition and phenol patterns. The study moose were divided into 2 groups; the winter group had low N in the digestive tract and high NDF and dry matter content, and the summer group had high levels of N and low NDF and dry matter content. The phenol platyphyllane, indicative of consumption of dormant silver birch (Betula pendula), was detected throughout the contents of the digestive tract in 2 animals in the winter group. The winter moose had higher NDF than summer moose, indicating the seasonal change in diet quality. In vitro organic matter digestibility (IVOMD) was not different between the summer and winter diets. The effect of birch phenols on IVOMD was concentration-dependent; differences between seasons were apparent at only the highest concentration. The 2 groups had marked differences in digestive content of major nutrients, NDF, and ability to digest forage which were consistent with typical variation in seasonal diet quality

SEASONAL VARIATION OF PHENOLS, NITROGEN, FIBER, AND IN VITRO DIGESTIBILITY IN SWEDISH MOOSE

Understanding how different components of food are processed and digested within the compartments of the digestive tract of large herbivores has important implications in their foraging behaviour, nutritional ecology, and techniques for measuring diet composition and nutritional quality of forage. Analysis of contents from different compartments of the digestive tract of moose in central Sweden showed that neutral detergent fiber (NDF) and nitrogen (N) content varied throughout the digestive tract and among individual moose (Alces alces). Total phenols (TP) had an inconsistent pattern throughout the digestive tract, possibly reflecting variation in diet composition and phenol patterns. The study moose were divided into 2 groups; the winter group had low N in the digestive tract and high NDF and dry matter content, and the summer group had high levels of N and low NDF and dry matter content. The phenol platyphyllane, indicative of consumption of dormant silver birch (Betula pendula), was detected throughout the contents of the digestive tract in 2 animals in the winter group. The winter moose had higher NDF than summer moose, indicating the seasonal change in diet quality. In vitro organic matter digestibility (IVOMD) was not different between the summer and winter diets. The effect of birch phenols on IVOMD was concentration-dependent; differences between seasons were apparent at only the highest concentration. The 2 groups had marked differences in digestive content of major nutrients, NDF, and ability to digest forage which were consistent with typical variation in seasonal diet quality

FORAGING ON NORWAY SPRUCE AND ITS POTENTIAL ASSOCIATION WITH A WASTING SYNDROME IN MOOSE IN SWEDEN

We studied a sudden occurrence of moose (Alces alces) browsing twigs and stripping bark of Norway spruce (Picea abies) that coincided temporally and spatially with a moose wasting syndrome in southern Älvsborg County in southwestern Sweden from 1990 to 1992. Spruce is a low preference forage for moose across Sweden and reports on its use are limited. This study reports on the importance of spruce as moose forage and its qualitative value relative to other more commonly used moose browse species in this region. Rumen contents from moose collected in autumn contained low proportions of spruce twigs (1.5-2.3%), and only 2 animals (n = 155) had spruce bark in the rumen. Generally, there was little browsing damage on spruce, although damage was severe in local areas. Spruce contained low concentrations of macroelements (crude protein, calcium, magnesium, potassium, and phosphorus) and trace elements (aluminum, cadmium, cobalt, copper, iron, manganese, and zinc), thereby minimizing this as a possible explanation for moose browsing. We used in vitro dry matter disappearance (IVDMD) as a measure of digestibility of spruce bark and twigs, and found no differences between spruce trees that had been bark stripped by moose and a control group of undamaged specimens. In addition, average IVDMD values of 14-25% dry matter of spruce bark were considerably lower than those found for more commonly used moose browse species in Sweden. We discuss these results with respect to the potential mechanisms underlying moose bark stripping of spruce. We cannot confirm that a potential linkage between foraging on spruce and a wasting syndrome in moose exists, and suggest that further research in this area is warranted

Älgbete i tid och rum

• Älgens biotopval och betesmönster är föränderliga i tid och rum – t.ex. mellan olika ungskogar och mellan år. • Tillgång och fördelning av olika foderväxter och markens produktionsförmåga påverkar dessa val. • Vanliga händelser som förändrar fodersituationen i landskapet, såsom skogsbruk, storm och brand blir därigenom viktiga för betningens och skogskadornas fördelning. • Snöförhållandena bidrar till en mellanårsvariation i betestryck och skogskador. Resultaten från skadeinventeringar blir därför svåra att använda i lokal förvaltning. • Betestrycket på tall kan förutsägas utifrån information om älgtäthet, fodertillgång och snöförhållanden, men det är svårare att förutsäga bete på vårt- och glasbjörk. • Älgen föredrar vissa trädslag framför andra. Rönn, asp och sälg löper störst risk att betas

THE INFLUENCE OF SILVICULTURAL CLEANING ON MOOSE BROWSING IN YOUNG SCOTS PINE STANDS IN FINLAND

Assessing the intensity of silvicultural cleaning in young stands of Scots pine (Pinus sylvestris), which are an important food source for moose (Alces alces), was studied in relation to the effects of feeding. Field data were collected in central Finland from 1990-96. The study area was divided into 13 silviculturally cleaned (1988-89) and seven untreated control stands. A second cleaning was done in all of the cleaned and untreated control stands in 1993-94. Six exclosures established in 1989 were also included in the study. White birch (Betula pubescens) was the main tree species removed by cleaning in both open areas and in exclosures. Total biomass consumed by moose in winter 1989-90, 1 year after the first cleaning, was significantly higher in untreated stands than in cleaned stands (33.3 kg/ha ± 3.7 SE vs. 12.0 kg/ha ± 3.7 SE, P < 0.01). Moose browsing on pine in silviculturally cleaned stands of pine was less intensive than in untreated ones. The total biomass consumed by moose in winter 1994-95, did not differ between cleaning treatments (10.4 kg/ha ± 2.2 SE vs. 11.0 kg/ha ± 5.1 SE, P = 0.90), nor did consumed pine biomass in winter 1995-95, 2 years after the second cleaning (4.6 kg/ha ± 1.3 SE vs. 9.0 kg/ha ± 3.8 SE, P = 0.20). Several factors were correlated with moose browsing on pine in winter 1994-95. Stepwise regression analysis revealed that total stem density and white birch density best explained moose browsing on pine. Significantly higher cumulative numbers of pine stem breakages and browsed pines occurred in sites cleaned once versus those cleaned twice during 1988-94. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of pine twigs prior to the second cleaning in 1993-94 was higher in the untreated stands than in the cleaned ones. However, in vitro dry matter digestibility did not explain the difference in browsing between cleaning treatments. Total phenol content of pine twigs was slightly higher in the clean stands than in the untreated stands. the preferred species of trees, aspen (Populus tremula), rowan (Sorbus aucuparia), and willows (Salix spp.), were taller in exclosures then in open areas in 1995. The differences were evidently caused by browsing. Results indicated that moose browsing was not high enough to reduce the stem density of less-preferred white birch, which was strongly competing with pine especially in the single-cleaning treatment. Thus, relatively early cleaning is needed in conditions with excess birches because they can increase the risk of moose damage to pine. The importance of a mixture of tree species as well as the timing of silvicultural cleaning in relation to moose browsing has to be taken into account when combining moose management and forest practices

SEASONAL VARIATION IN WEIGHT OF FUNCTIONAL SEGMENTS OF THE GASTROINTESTINAL TRACT AND ITS CONTENTS IN YOUNG MOOSE (ALCES ALCES)

Quantitative seasonal variation of bio mass among segments of the gut wall and associated contents of moose has not been previously reported. From a sample of 6- to 13-month old moose collected in southcentral Sweden, gastrointestinal tracts were divided into nine functionally distinct segments. Each segment was measured for live weight and length of the wall, and wet and dry weight of the contents. Dry matter digesta was greater in winter than in summer with all segments except the small intestine. Live weight of the wall and its weight relative to other segments was significantly greater in the rumenoreticulum and abomasum during summer than in winter. Weight variations by season and among segments of the tract are discussed in terms of nutritional strategies and adaptations

The cost-effectiveness of radiofrequency catheter ablation as first-line treatment for paroxysmal atrial fibrillation : results from a MANTRA-PAF substudy.

AIM: The aim of this prospective substudy was to estimate the cost-effectiveness of treating paroxysmal atrial fibrillation (AF) with radiofrequency catheter ablation (RFA) compared with antiarrhythmic drugs (AADs) as first-line treatment. METHODS AND RESULTS: A decision-analytic Markov model, based on MANTRA-PAF (Medical Antiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation) study data, was developed to study long-term effects and costs of RFA compared with AADs as first-line treatment. Positive clinical effects were found in the overall population, a gain of an average 0.06 quality-adjusted life years (QALYs) to an incremental cost of €3033, resulting in an incremental cost-effectiveness ratio of €50 570/QALY. However, the result of the subgroup analyses showed that RFA was less costly and more effective in younger patients. This implied an incremental cost-effectiveness ratio of €3434/QALY in ≤50-year-old patients respectively €108 937/QALY in >50-year-old patients. CONCLUSION: Radiofrequency catheter ablation as first-line treatment is a cost-effective strategy for younger patients with paroxysmal AF. However, the cost-effectiveness of using RFA as first-line therapy in older patients is uncertain, and in most of these AADs should be attempted before RFA (MANTRA-PAF ClinicalTrials.gov number; NCT00133211)