Comparative aspects of volatile fatty acid production in reindeer {Rangifer tarandus tarandus) in northern Norway and on South Georgia

Svein D Mathiesen,Wenche Sørmo,Tove H Aagnes Utsi

doi:10.7557/2.20.4.1515

Abstract

Dietary influence on pH and volatile fatty acids concentrations and production rates in the rumen and distal fermentation chamber (DFC) was investigated in Norwegian reindeer (Rangifer t. tarandus) on South Georgia in summer (SG), and in northern Norway in late summer (NS) and winter (NW). Mean [standard deviation (s)] ruminal pH was similar in SG teindeet (6.46, s = 0.13) and NW reindeer (6.45, s = 0.19), but significantly different from NS reindeer (6.87, s = 0.08)(P &lt; 0.05). Mean DFC pH in SG reindeer (6.92, s = 0.12) and in NS reindeer (6.70, s = 0.16) did not differ significantly. In NW reindeer DFC pH (6.26, s = 0.20) was significantly lower than in the SG and NS animals (P &lt; 0.05). Mean ruminal concentration of volatile fatty acids (VFA) was 92.4 mM (s = 13-3) in SG reindeer, which was significantly larger (P &lt; 0.05) than in NS (71.5 mM, s = 10.2) and NW reindeer (73.3 mM, s = 9.7). In DFC mean VFA concentration was 51.3 mM (s = 11.7), and 48.8mM (s = 14.5) in SG and NW reindeer respectively, and significantly less than in NS reindeer (86.7mM, s = 5.4) (P &lt; 0.05). Mean daily ruminal VFA rate of production was 246.4 kj/kg BM"" in SG teindeer, compared to 195.6 kj/kg BM"" in NS and 193.4 kJ/kgBM0 75 in NW reindeer. Mean daily VFA rate of production in DFC was 8.3 kj/kg BM0 75 in SG reindeer compared to 6.2 kj/kg BM07' in NS and 3.0 kj/kg BM"75 in NW reindeer. The summer pastures on SG and NS were of moderate quality in terms of ruminal VFA production. In winter in northern Norway when forage quality was assumed to be low, both ruminal and DFC pH were low. The high fermentation rate in winter was probably due to easily digestible carbohydrates in the lichens eaten. DFC seems to be of minor importance in these reindeer in terms of VFA energy yield.

Highlights

In northern Norway semi domesticated reindeer (Rangifer t. tarandus) migrate 150-350 k m seasonally between inland pastures where they eat lichens, woody plants and some dry grasses i n winter, to coastal summer pastures where graminoids and herbs are selected to a greater extent
Ruminal and distal fermentation chamber (DFC) pH The p H of rumen fluid depends on the plant quality of the diet eaten, the rate and volume of salivary buffer secretion, and the rate of production and absorption of volatile fatty acids (VFA) across the rumen wall (Church, 1983)
In S G reindeer as much as 90% of all plant particles in the rumen consisted of grasses, compared to 6 5 % in N S and 21% in N W reindeer

Summary

Introduction

In northern Norway semi domesticated reindeer (Rangifer t. tarandus) migrate 150-350 k m seasonally between inland pastures where they eat lichens, woody plants and some dry grasses i n winter, to coastal summer pastures where graminoids and herbs are selected to a greater extent. The. Rangifer, 20 (4), 2000 chemical composition of lichens consists of as much as 7 5 % lichen hemi-cellulose, including xylan and lichen starch lichenins in addition to small amounts of cellulose and protein, while woody plants in winter are highly lignified (Person et al, 1980; Mathiesen et al, 1999b). 20 (4), 2000 chemical composition of lichens consists of as much as 7 5 % lichen hemi-cellulose, including xylan and lichen starch lichenins in addition to small amounts of cellulose and protein, while woody plants in winter are highly lignified (Person et al, 1980; Mathiesen et al, 1999b) I n this century semi domesticated Norwegian reindeer were introduced to the sub-Antarctic island of South Georgia where they eat mainly grasses all year round, independent of lichens and woody plants (Leader-Williams, 1978; 1988). In view of the extremely different diets of reindeer on South Georgia and in Norway, ruminal and D F C carbohydrate fermentation were evaluated by investigating the p H , rate of production and concentrations of VFAs using the zero-time technique originally described by Caroll & Hungate (1954)

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Conclusion