Päivi Soppela

Does climate change influence the availability and quality of reindeer forage plants

The northward and upward movement of the tree line and gradual replacement of lichens with vascular plants associated with increasing temperatures and nutrient availability may change the reindeer pastures in Northern Fennoscandia. The productivity of reindeer forage will most probably increase, but their protein (nitrogen) concentrations may decrease because of higher temperatures and CO2 concentration. In the long term, the nutritive value of forage will depend on the mineralization rate and nutrient uptake from the soil. Enhanced UV-B is likely to increase the concentration of phenolics, decreasing forage quality and choice, but reindeer may adapt to increased phenolics. Increased winter precipitation, the occurrence of ice layers, deeper snow cover, and the appearance of molds beneath the snow cover may reduce the availability and/or quality of reindeer forage, but prolongation of snowless periods might have the opposite effect. The net balance of negative and positive effects will vary regionally depending on the climate, bedrock, vegetation, reindeer herding systems and socio-political factors. Multidisciplinary research is needed most importantly on the effects of the changing winter climate on reindeer forage, and the effect of modified forage quality on reindeer physiology.

The chemical response of reindeer summer pasture plants in a subarctic peatland to ultraviolet (UV) radiation

Reindeer management is an important livelihood in northern Fennoscandia. There are about 0.7 million reindeer in Finland, Sweden and Norway and approximately 300,000 calves are born every year. The survival of reindeer is highly dependent on renewable natural resources, or ecological preconditions provided by natural pastures (Helle et al. 1990; Reimers 1997; Kumpula et al. 1998). Summer pastures play a central role in the growth of reindeer. Reindeer calves are born in spring and their growth is most rapid during the first few months of life when they graze on summer pastures. Reindeer are mainly slaughtered during autumn. Most of the slaughtered animals are calves (>70 %), and the productivity of reindeer management and income of reindeer herders is highly dependent on the growth success of the calves during the summer. Body mass and fat stores that reindeer are able to accumulate on the summer pastures significantly affect the condition of reindeer and their survival over winter (Helle et al. 1987; Soppela 2000; Soppela and Nieminen 2002). The diet of reindeer is markedly different between summer and winter. During summer, reindeer feed on green vegetation such as grasses, sedges, shrubs, herbs, and leaves of deciduous trees (Warenberg et al. 1997). This diet has a high content of energy, protein, and minerals (Nieminen and Heiskari 1989; Staaland and Saebo 1993) and it enables rapid growth of reindeer and accumulation of muscle and fat. During autumn and early winter, reindeer gradually change to a diet consisting mainly of lichens and wintergreen parts of shrubs, sedges, and grasses (Warenberg et al. 1997). The main winter feeds in many areas are ground lichens (Cladina spp.; Kumpula 2001). Winter diet has a low content of nitrogen and minerals (Nieminen and Heiskari 1989; Staaland and Saebo 1993; Danell et al. 1994; Storeheier et al. 2002). Lichens

Localization, cellular morphology and respiratory capacity of “brown” adipose tissue in newborn reindeer

1. The localization and cellular morphology of adipose tissue was studied by light, fluorescence and electron microscopy in reindeer between 2 weeks pre partum and 4.5 months post partum during calving, and the subsequent growth period. The respiratory capacity of the adipose tissue was examined in terms of morphometric mitochondrial volume and cytochrome-c oxidase or succinate dehydrogenase activity. 2. Adipose tissue was located at specific anatomical sites in the newborn reindeer (from 0 to 2 days of age). The perirenal-abdominal depot was the largest location (32%) followed by the inter(pre)scapular (18%) and sternal (12%) depots. Internal depot dominated over external or peripheral depots (66-34%). The locations of adipose tissue were largely similar in foetal, newborn and young reindeer. 3. The adipose tissue of the newborn reindeer had all the typical cell morphological characteristics of brown adipose tissue: abundant mitochondria, multilocular fat, high vascularization and a dense spot-like sympathetic innervation between the adipocytes. In the young reindeer, however, it resembled white adipose tissue, being almost totally unilocular with few mitochondria. 4. There was a significant correlation between morphometric mitochondrial volume and cytochrome-c oxidase activity (r = 0.848) in the adipose tissue. Mitochondrial volume, cytochrome-c oxidase and succinate dehydrogenase activity were highest after birth and decreased to almost an undetectable level during the first month. A parallel decrease occurred in the amount of brown adipose tissue from birth (1-2%) to the age of about one month (0.3%). 5. It is concluded that the distinct cell morphological features and high respiratory capacity of the adipose tissue indicate the presence of brown adipose tissue at specific anatomical locations in newborn reindeer. A marked progression towards the characteristics of white adipose tissue then takes place at the same locations during the first month. The results suggest the fundamental significance of brown adipose tissue for non-shivering thermogenesis in newborn reindeer.

Thermoregulation in reindeer

Thermoregulation was studied in Finnish reindeer (Rangifer tarandus L) on captive and herded individuals during 1977-85. Newborn calves maintained a high rectal temperature (Tre) (+39 to +41°C) even at —23°C by increasing heat production 5- to 6-fold through non-shivering thermogenesis, stimulated by cold-induced noradrenaline (NA). Plasma NA and thyroxine (T4) were high (18 ng/ml and 459 nmol/1) in neonatal reindeer. Sensitivity to exogenous NA was lost during the first 3-4 weeks of life. At +20°C and above, calves increased Tre (ca 1°C), oxygen consumption and heart rate, thereby showing poor heat tolerance. Thermal conductance was low in a cold environment, but rose sharply as ambient temperature (Ta) increased above + 10°C. The Tre of adults (+ 38 to +39°C) was independent of Ta (—28 to +15°C). Coarse (hollow) hair density and length in adults averaged 2000/cm2 and 12 mm on the legs, 1000/cm3 and 30 mm on the abdomen and 1700/cm2 and 30 mm on the back (calves 3200/cm2, 10 mm), respectively. The dependence of skin temperature on the Ta was linear in excised fur samples, but complex in living animals being strongest in the legs. Serum adrenaline correlated with the weight, age and total lipids. Serum NA and dopamine-fi-hydroxylase were highest in spring and decreased by autumn. Serum T4 was highest in summer and lowest in spring.

Adipose tissue fatty acid composition from different body sites in reindeer calves during autumn and spring

Seasonal variation in amount and metabolic activity of adipose tissue is prominent in reindeer, as in most arctic Cervidae species. Adipose tissue is the primary storage site for fatty acids, which serve as energy reserve, but the composition of which may also have function in thermoregulation and act as mechanichal support and protection for organs. Ruminant storage fat quality is less exposed to diet-ind.uced changes than in monogastric animals (e.g. Christie 1981). As a response to varying functional demands, controlled seasonal and site-specific differences in fat composition would be expected. Fatty acid composition of adipose tissue from different body sites of slaughtered reindeer calves was analysed in November ( N = 10) and in Apr i l ( N = 6) at the age of 6 and 12 months, respectively. Adipose tissue was sampled from three external (interscapular, peristernal and caudal) and three internal (pericardial, perirenal and intralumbar) anatomical locations. Total l i pids were extracted with methanol-chloroform (1:1) and their fatty acid composition was analysed by gas-liquid chromatography. Altogether 16 individual fatty acids from 14 to 20 carbon chain lengths were identified from the total lipids of adipose tissue in different body sites. The dominant fatty acid was oleic acid (18:1) followed by stearic acid (18:0) and palmitic acid (16:0) in each external site and in perirenal and intralumbar fats. Other fatty acids had smaller percentages (0-3 %). High degree of oleic acid (35-37 % in November and 40-47 % in April) agrees earlier studies (Garton & Duncan 1971). In perirenal fat higher proportions of 18:0 (34 %) were found compared to other sites (24-30 %). Pericardial fat differed remarkably from others having highest proportion of 16:0 (31 %) followed by 18:0 and 18:1 (both 29 %). Adipose tissue was predominantly saturated in both seasons (range 48 to 66 %), but there was a trend towards unsaturation in each body site excluding pericardial fat during Apr i l . In agreement with earlier studies (Garton & Duncan 1971) we found that internal body fats from perirenal and pericardial deposits were more saturated than external fats. Polyunsaturated fatty acids had a smaller proportion during spring than during autumn in each body site. The highest proportion (3.2 %) of polyunsaturated fatty acids was measured in pericardial fat in November. Branched-chain fatty acids were highest (1.9 %) in pericardial fat in Apr i l . Storage fats in reindeer during starvation are used sequently starting from subcutaneous deposits followed by visceral fats, and finally, bone marrow fat (see Nieminen & Laitinen 1986). Changes in fatty acid composition of external fats between autumn and spring may reflect desaturation or preferential order in uptake of fatty acids during winter. Higher proportion of oleic acid in external fats refers to more fluid properties compared to internal fats (18:1 acid melts at + 15°C, 16:0 and 18:0 at + 64 and + 69°C, respectively; Irving & Krog 1955).

2nd Nordic NJF Seminar on Reindeer Husbandry Research "Reindeer herding and land use management - Nordic perspectives"

The 2nd NJF Seminar on Reindeer Husbandry Research was held at the Arctic Centre, University of Lapland, Rovaniemi, Finland from 19 to 21 October 2014. The seminar was organised under the framework of Reindeer Husbandry Research Section of NJF (Nordic Association of Agricultural Scientists), established in 2012. Over 100 Nordic and international delegates including researchers, managers, educators, students and reindeer herders participated in the seminar.