Digestive studies with a feed developed for realimentation of starving
reindeer
Harald Sletten a n d Knut Hove
1
1
2
Norwegian Directorate for Reindeer Husbandry, 7760 Snåsa, and Department of Animal Science, Agricultural University of Norway, P . O . box 25, 1432 ÅS-NLH, Norway.
2
Correspondence to H . Sletten at the above adress.
Abstract: The properties of three different feeds were compared when offered to reindeer calves as single feeds
after a starvation period of the 48 h. The feeds were lichen and two pelleted commercial reindee*- feeds, RF-71
and RF-80. The two latter differed in concentration of readily digestible carbohydrates (high in RF-71) and in
the inclusion of seaweed meal in RF-80. Seven calves were offered the three diets in a latin square design.
Measurements involved feed intake and rumen concentrations of volatile fatty acids, ammonia and p H during
a five day period after the end of the starvation period. Feeding RF-80 gave rise to higher feed intakes and
more rapid normalisation of rumen V F A and ammonia concentration than the other pelleted feed. Rumen
p H reached a minimum of 5.4 in animals fed RF-71, while the average minimum p H during the observation
period was 6.1-6.2 when RF-80 was given. Inappetance for 1-2 days after refeeding occurred only with RF-71.
RF-80 has now replaced RF-71 as the commercial reindeer feed in Norway.
K e y w o r d s : emergency feeding, types of feed, effects, problems, N o r w a y
Rangifer, 10 (1): 3 1 - 3 7
Sletten, H . & Hove, K.
1990. F o r d ø y e l s e s f o r s ø k
m e d et f o r u t v i k l e t t i l o v e r g a n g s f o r i n g
av s v e l t e n d e r e i n .
Sammendrag: En har sammenlignet egenskapene til tre forskjellige fortyper gitt til reinkalver som eneste for
etter en sveltperiode på 48 timer. Fortypene var reinlav og to pelletterte, kommersielle reinfor: RF-71 og RF80. De siste to adskilte seg fra hverandre i konsentrasjonen av lettfordøyelige karbohydrater (høyest i RF-71)
og i innblanding av tangmel i RF-80. Syv reinkalver ble gitt de tre dietter i «latin square» forsøksmønster.
Målingene omfattet: forinntak, konsentrasjon i vominnhold av flyktige fettsyrer (VFA) og ammonium samt
verdier av p f i gjennom en fem-dagers periode etter avsluttet sveltperiode. Foring med RF-80 økte forinntaket
og forårsaket en raskere normalisering av V F A - og ammoniumkonsentrasjonene enn foring med RF-71. p f i
nådde et minimum på 5,4 hos dyr som fikk RF-71, mens gjennomsnittlig verdi av p H gjennom observasjonsperioden var 6,1-6,2 når det ble gitt RF-80. Apetittløshet i 1-2 dager etter gjenopptatt foring inntraff bare ved
bruk av RF-71. RF-80 har nå erstattet RF-71 som kommersielt for til rein i Norge.
Rangifer, 10 (1): 3 1 - 3 7
Introduction
Ice crusting of w i n t e r pastures is a recurrent
p r o b l e m for reindeer i n m a n y areas. Ice o n top
of the vegetation may result i n reduced feed i n -
Rangifer, 1 (10), 1990
take or even complete starvation. Supplementar y feeding is therefore often necessary. Feeds
w i t h a high energy concentration are usually
advocated under such circumstances, because of
31
the high expense of transporting feed i n b u l k .
F o r more than a decade a pelleted reindeer feed
(RF-71, Jacobsen & Skjenneberg, 1979) has been
the o n l y feed c o m m e r c i a l l y available to N o r w e gian reindeer herders. T h e m a i n p r o b l e m w i t h
this concentrate is its relatively high starch content, w h i c h easily produces r u m e n acidosis
w h e n the feed is offered ad lib to starving reindeer. S o d i u m bicarbonate was added to buffer
RF-71 (Bøe & Jacobsen, 1981) i n an attempt to
reduce the tendency t o develope acidosis. T h e
buffering effect, however, has been inadequate
(Bøe et al 1982).
Lichens, i n contrast to concentrates, cause
o n l y a moderate reduction i n the p H of the r u men w h e n given ad lib after a p e r i o d of starvat i o n . Seaweeds contain carbohydrates similar to
the carbohydrate fraction of lichens and represent a readily available feed source i n N o r w a y
(Jensen et al. 1968): A reindeer feed w i t h seaweed meal as part of the carbohydrate fraction
(RF-80) gave good performance i n feeding experiments (Bøe et al. 1982). T h i s feed has been
used extensively i n preparatory feeding of reindeer before slaughter i n 1987-89 i n areas where
radiocasium c o n t a m i n a t i o n f r o m the C h e r n o b y l
accident p r o h i b i t e d slaughter directly f r o m pasture (Sletten 1989). A gradual transfer f r o m l i chen to R F - 8 0 has been recommended, since n o
data were available regarding the properties of
R F - 8 0 w h e n given as the single feed after a per i o d of starvation.
T h e purpose of this study was to compare r u men fermentation and feed intake of R F - 7 1 ,
R F - 8 0 and lichens w h e n offered alone after
short periods of starvation. In addition, feed values of these diets were assessed i n c o n v e n t i o n a l
digestibility trials.
Table 1. Chemical composition of the feeds (g per
100 g of dry matter).
D r y matter
O r g a n i c matter
Crude protein
C r u d e fat
C r u d e fiber
N-free extracts
Ash
32
RF-71
90.2
93.8
13.0
4.4
10.8
65.6
6.2
RF-80
89.4
94.4
13.0
6.0
12.5
62.9
5.6
Lichen
30.6
98.0
3.6
2.9
39.5
52.0
2.0
Table 2. Composition of the pelleted feeds given as a
weight percentage.
RF-71*
25
38
15
15
Grass meal
G r o u n d barley
G r o u n d oats
W h e a t bran
Hydrogenated
marine fats
Sea weed meal
D r i e d fish silage
S o d i u m bicarbonate
3
-4
RF-80
40
20
20
3
15
2
-
* A mixture of microminerals (0.3 g/kg) added.
Materials and methods
Animals
Seven male semi-domesticated reindeer calves
f r o m southern N o r w a y were taken to the
A g r i c u l t u r a l U n i v e r s i t y . T h e animals were tied
by head collars i n i n d i v i d u a l pens. T h e y readily
accepted feeding and handling. Antiparasite treatment (Ivermectin) was given and the calves
were vaccinated against Clostridium
perfringens
enterotoxaemia. Cannulas were inserted i n the
dorsal r u m e n b y conventional techniques after
one week.
Feeds
T h e c o m p o s i t i o n of the t w o types of concentrates tested i n the experiment are given i n table
1. R F - 7 1 is a s o d i u m bicarbonate buffered, pelleted reindeer feed w i t h ground barley and grou n d oats as the major energy source. In R F - 8 0
some of the barley and the wheat bran is replaced b y grassmeal and seaweed meal (Table 2).
T h e concentrates were produced f o r the experiment b y S t o r m o l l e n , T r o n d h e i m . Lichens used
i n the trials consisted m a i n l y of Cladonia alpestris w i t h some Cetraria nivalis, CI. arbuscula and
CI. rangiferina.
Experimental
procedure
T h e experiment was conducted as a 3 x 3 latin
square w i t h 2 o r 3 calves per group. T h e calves
were trained t o eat a l l experimental feeds p r i o r
to the experiment.
Rangifer, 1 (10), 1990
T h e testing of each feed was conducted according to the f o l l o w i n g schedule:
l i d feeding w i t h lichen (ad lib)
3 d feeding w i t h restricted amounts of l i chen (0.5, 0.5 and 0.3 k g d r y matter
( D M ) per day, respectively)
2 d complete starvation
5 d experimental p e r i o d w i t h observations of feed intake a n d digestive parameters
E a c h feed (lichen, R F - 7 1 o r RF-80) was offered ad lib. d u r i n g the experimental p e r i o d .
F o o d was given at 08.00 and the amount consum e d was recorded b y w e i g h i n g of left overs at
10.00, 12.00, 14.00, 16.00, 20.00, 24.00 a n d before feeding the next m o r n i n g .
R u m e n contents (50 ml) was w i t h d r a w n f o r
analysis t h r o u g h the cannulae each time feed
c o n s u m p t i o n was measured. T h e r u m e n l i q u o r
was strained t h r o u g h a double layer of cheese
c l o t h and 5 m l of the filtrate, acidified w i t h 5
m l of 4 % f o r m i c acid, was stored at 4 ° C u n t i l
analysis.
Digestibility
trials
T h e digestibility of the experimental feeds was
determined i n feeding trials w h i c h lasted 21 d.
A f t e r a 11 d adjustment p e r i o d faeces and urine
were collected f o r 10 d.
8.0
7.5
B
o
<
P-,
>
3
4
5
6
TIME (days)
Fig. 2. Rumen concentrations of volatile fatty acids
and ammonium-N in reindeer calves fed l i chen ad lib. day 1 and 2, restricted amounts
of lichen on days 3-5, and no feed for the
rest of the period. The data shown are averages and standard deviations of three samples
per day from each of 7 animals.
Chemical analyses
T h e p H o f r u m e n l i q u i d was measured i m m e diately after f i l t r a t i o n . V o l a t i l e fatty acids
( V F A ) were measured b y c o n v e n t i o n a l gas
c h r o m o a t o g r a p h y w i t h C r o m o s o r b 101 (60-80
mesh) as the stationary phase. A m m o n i a - n i t r o gen ( N H 3 - N ) was measured c o l o u r i m e t r i c a l l y
b y an automated m o d i f i c a t i o n of the indophe¬
n o l reaction. T h e c o m p o s i t i o n of feed a n d faeces was determined according to the Wendee
procedures ( A O A C , 1977).
Statistical analyses
T h e data f r o m the experiment (latin
sign) were analysed w i t h the general
del ( G L M ) procedures (SAS Institute
value b e l o w 0.05 was taken to be
significant.
7.0
6.5
square delinear m o 1985). A p
statistically
Results
6.0
3
4
5
TIME (days)
Fig. 1. Rumen p H in reindeer calves fed lichen ad
lib. day 1 and 2, restricted amounts of lichen
on days 3-5, and no feed for the rest of the
period. Average and standard deviation of observations from 7 calves.
Rangifer, 1 (10), 1990
Preparatory feeding and starvation
R u m e n p H showed d i u r n a l fluctuation between
6.5 and 6.8 i n animals fed ad libitum but i n creased to about 7.6 at the e n d of the starvation
(Fig. 1). R u m e n V F A concentrations declined
during starvation f r o m 55 mmol/1 to a mean o f
30 mmol/1. Simultaneously a m m o n i a - N concentrations increased to about 15 mmol/1 (Fig. 2).
33
N o significant differences i n feed intake were
observed between each p e r i o d of preparatory
feeding. Concentrations of V F A or N H 3 - N
were nearly equal at all preparatory periods,
signifying that a n o r m a l r u m e n mileue was established r a p i d l y after the experimental periods.
Experimental
period
Feed intake: T h e animals showed a great appetite after the realimentation regardless of w h i c h
feed they were offered. T o t a l feed c o n s u m p t i o n
varied between 600 and 900 g D M o n the first
day (Fig. 3). O n the second day animals fed
R F - 7 1 or lichen reduced their intake to approx i m a t e l y 500 g D M . A n i m a l s offered R F - 8 0
consumed av average of 1300 g. T h i s high level
was sustained o n the second day and further i n creased throughout the p e r i o d of refeeding.
C o n s u m p t i o n of RF-71 also increased after the
second day but it never reached the level of
R F - 8 0 . T h e daily c o n s u m p t i o n of lichens was
approximately 500 g D M for the rest of the per i o d . T h i s intake was similar to the level of
c o n s u m p t i o n d u r i n g preparatory feeding.
Rumen pH: p H valus were lowest i n the animals fed RF-71 (Fig. 4). T h e lowest levels occurred 16 h after realimentation, w h e n the
mean m i n i m u m p H was 5.4. In one animal the
p H of the r u m e n l i q u o r was 4.7. M i n i m a l values for animals fed R F - 8 0 or lichen were observed 26-28 h after refeeding and were considerab l y higher (6.1-6.2). R u m e n p H showed d i u r n a l
fluctuations around a means of 6.8 f r o m day 2
onwards i n animals fed w i t h R F - 7 1 or R F - 8 0
and 6.6 i n animals fed w i t h lichens.
Differences i n the decline i n p H levels first
day after realimentation were compared b y an
analysis of variance i n v o l v i n g type of feed, intake, animal and experimental p e r i o d as independent variables. O f the variables included i n the
m o d e l , o n l y feed had a significant c o n t r i b u t i o n
( p < 0 . 0 1 , R = 0.74).
2
Rumen VFA: T o t a l V F A concentrations i n creased after realimentation i n all cases (Table
3). R F - 8 0 caused the most rapid increase and
V F A concentrations stabilized at approximately
70 mmol/1 o n day 2. W i t h R F - 7 1 a slower i n crease was observed. A f t e r 5 days, average concentrations of r u m e n V F A s o n the t w o pelleted
feeds were equal. W h e n lichens were given after
starvation, r u m e n V F A levels stabilized at 5 5 34
TIME (days)
Fig. 3. Daily cumulative intakes of feed in 7 reindeer
calves given ad lib. access to either lichen, RF71 or RF-80 after 3 days of restricted feeding
and 2 days of complete starvation. Averages
and standard deviations.
60 mmol/1 w h i c h is similar to levels observed
before starvation.
Rumen NHj-N
decreased f r o m the high levels
d u r i n g starvation for all feeds tested. Prestarvat i o n levels were reached more r a p i d l y i n the
R F - 8 0 fed animals than i n animals receiving R F 71 (Table 3).
Rangifer, 1 (10), 1990
Table 3. Rumen concentrations of volatile fatty acids
and N H - N (mmol/1) from day 1 to day 5
of the experimental period. (Mean ± SD of
7 animals).
3
day
RF-71
RF-80
.. N H 3 - N ...
Lichen
1
2
3
4
5
11.1 ± 5 . 8
11.7±7.2
8.9±5.7
4.5±3.6
4.9 ± 5 . 0
12.1 ± 2 . 2
6.2±5.1
3.8±3.1
3.3±2.1
4.0±2.7
8.9 ± 7 . 2
8.2±9.4
1.8±2.1
1.7± 1.0
2 . 0 ± 1.1
1
2
3
4
5
43 ± 2 6
47 ± 3 3
56 ± 1 9
62 ± 1 3
6 7 ± 14
ved w i t h R F - 8 0 . I n d i v i d u a l v a r i a t i o n i n feed i n take was highest w i t h R F - 7 1 : several calves refused to eat o r consumed a m i n i m u m o n day 2
and 3 of the realimentation p e r i o d .
O n e explanation f o r the l o w appetite f o l l o w i n g refeeding w i t h R F - 7 1 is the large d r o p i n
8.0
VFA
46
71
69
67
71
±17
± 13
±10
±12
±16
44 ± 1 9
5 5 ± 16
57± 9
54± 9
58 ± 9
Digestibility and nutritive value of the feeds
T h e digestibility of all components tested were
generally higher f o r R F - 8 0 than f o r R F - 7 1 but
the difference was significant o n l y f o r crude f i ber ( p < 0.001. Table 4). T h e components of the
lichen had a higher digestibility than the pelleted feeds except f o r the crude p r o t e i n . T h e
energy value of RF-80 was significantly higher
than R F - 7 1 , w h e n expressed b o t h as metabolizable and as net energy (Table 5).
Discussion
W h e n lichens were used d u r i n g refeeding normal concentrations of the studied r u m e n c o m ponents were r a p i d l y reestablished. A f t e r a higher feed intake o n the first day, the animals
consumed the same amounts of lichen d r y matter as i n the prestarvation p e r i o d . A n artificial
feed ideally should, i n the same w a y as lichen,
be palatable and establish n o r m a l r u m e n funct i o n q u i c k l y w h e n given to starving animals.
R F - 8 0 had properties similar to lichens i n these
respects. I n fact, r u m e n p H was slightly better
maintained w i t h RF-80 than w i t h lichens d u r i n g the first day after refeeding. R F - 8 0 h a d excejlent palatability since the reindeer consumed
about 900 g the first day and increased their
feed intake further o n the f o l l o w i n g days. B y
contrast, the animals fed R F - 7 1 showed a considerable drop i n appetite o n day 2 and never
subsequently reached the levels of intake obser-
Rangifer, 1 (10), 1990
2
3
4
TIME (days)
Fig. 4. Changes in p H of rumen fluid in 7 reindeer
calves given ad. lib. access to either lichen,
RF-71 or RF-80 after 3 days of restricted feeding and 2 days of complete starvation. Averages and standard deviations.
35
Table 4. Digestibility coefficients for the chemical components in the feeds used. Average of 4 animals for R F 80 and lichen and two animals for RF-71.
Ration
Dry
matter
Organic
matter
Crude
protein
Crude
fat
Crude
fiber
RF-71
73.2
a
73.7
a
68.0
91.5
30.0
a
80.8
RF-80
78.3
a
79.4
a
71.2
Lichen
86.2
b
87.1
b
a
a
20.8
b
a
N-freeextracts
93.7
a
59.4
b
83.6
89.7
b
96.5
C
82.5
Values in the same coloumn with different superscripts are si{ mificantly different (p<0.05-p< 0.001).
p H w h i c h occurred o n day 1. T h i s f i n d i n g is i n
accordance w i t h earlier observations w i t h R F - 7 1
(Bøe et al, 1982). T h e p H of r u m e n l i q u i d i n
animals fed lichen ranges f r o m 6.0-6.8 (Åhman
& Åhman 1980, Bøe et al, 1982, Mathiesen et
al, 1984). R u m e n p H values never dropped bel o w 6.0 during feeding w i t h R F - 8 0 , and averages were maintained at about p H 6.5. In other
r u m i n a n t species changes i n the m i c r o b i a l flora
takes place w h e n mean p H drops b e l o w 6.0.
Reduced g r o w t h of cellulolytic bacteria and a
rapid g r o w t h of lactic acid fermenters are c o m m o n findings ( K a u f m a n n et al 1979, H o o v e r
1986).
Concentrations of nitrogen free extracts and
crude fibre are similar i n RF-71 and R F - 8 0 . T h e
major difference between the c o m p o s i t i o n of
the t w o feeds resulted f r o m an increase i n the
content of grass meal and a reduction of grou n d barley i n R F - 8 0 , and f r o m an exchange of
wheat bran w i t h seaweed meal. T h e concentrat i o n of readily fermentable carbohydrates is
thus l o w e r i n R F - 8 0 than i n R F - 7 1 . T h e p r o perties of the carbohydrate fractions are probab l y the major difference explaining the l o w p H
values and p o o r appetite after feeding of R F - 7 1 .
R e d u c t i o n of fiber digestibility resulting f r o m
an i n h i b i t i o n of the activity of c e l l u l o l y t i c bacteria is often observed w i t h diets r i c h i n readily
fermentable carbohydrates (Ørskov 1982, Bøe,
1989). In accordance w i t h this, digestibility of
the crude fibre fraction of R F - 7 1 was l o w e r
than R F - 8 0 (table 4). T h i s m a y be related to
l o w r u m e n p H values, but m a y also be secondary to differences i n the c o m p o s i t i o n of the f i ber fraction of the t w o feeds.
T h e p r o d u c t i o n of V F A s is l o w i n a starved
r u m e n . Bacterial counts fall r a p i d l y w i t h the
length of a starvation p e r i o d (Mathiesen et al
1984). Lactic acid fermenting bacteria reproduce
r a p i d l y w h e n readily digestible carbohydrates
36
are fed to a starving animal, w h i l e the p o p u l a t i o n of c e l l u l o l y t i c bacteria require longer time
to m u l t i p l y and thus develop a h i g h fermentative capacity. Lactic acid concentrations were not
measured i n the present experiment. Earlier studes have h o w e v e r s h o w n that h i g h concentrations of lactic acid were present after feeding of
R F - 7 1 to starved reindeer (Bøe et al 1982). W e
assume that differences i n r u m e n p H observed
w h e n feeding the t w o pelleted feeds can be attributed to differences i n the rate of lactic acid
production.
T h e polysaccharide fraction of seaweeds resemble the l i c h e n i n and isolichenin f o u n d i n l i chens, except for some differences i n the branching of the glycoside chains of the molecules
( C u l b e r s o n , 1969). T o o u r knowledge the digest i o n of these polysaccharides has not been studied i n ruminants, but we suggest that the patterns of fermentation of lichens and seaweed
meal i n the r u m e n of o u r experimental animals
were similar. T h e digestibility of seaweed meal
and lichens i n sheep is about 50 % of the organic matter. In reindeer, o n the other hand, l i chens are digested to an extent of 70-90 %
( N o r d f e l d t et al
1961, L e n v i k & F j e l l h e i m
1977, Jacobsen & Skjenneberg 1977). W e expect
that reindeer have a m i c r o b i a l flora better suiTable 5. Nutritive value of feeds determined in digestibility trials. Energy values given are calculated per kg of dry matter and given in M J
(Metabolizable energy) or as fattening feed
units (Net energy).
Ration
Metabolizable
energy
N e t energy
RF-71
Rf-80
Lichen
10.8
12.1
12.6
0.99
1.10
1.00
Rangifer, 1 (10), 1990
ted for an efficient fermentation of marine algae
w h e n the r u m e n microbes have been adapted to
lichen because of the s i m i l a r i t y i n carbohydrate
fractions of seaweed meal and lichen. T o o u r
knowledge this has not been studied.
In c o n c l u s i o n , the experiment demonstrated
that R F - 8 0 was superior to R F - 7 1 as a feed for
realimentation of starved reindeer b o t h w i t h regard to appetite and to several different parameters of r u m e n f u n c t i o n .
References
A O A C Association of Official Analytical Chemists, 1977. Official Methods of Analysis, 11. edition. - Washington D . C . : Association of Official
Analytical Chemists.
Bøe, U . B. & Jacobsen, E. 1981. Foringsforsøk med
ulike typer for til rein. - Rangifer 1: 39-43.
Jacobsen, E . & Skjenneberg, S. 1977. Fordøyelighet
av lav til rein. - Forskning og forsøk i landbruket.
28: 63-67.
Jacobsen, E . & Skjenneberg, S. 1979. Forsøk med
ulike forblandinger til rein. - Meld. Norges Landbr.
Høgsk. 58: 1-34.
Jensen A., Nebb, H . & Sæter, E . A. 1968. The value of Norwegian seaweed meal as a mineral supplement for dairy cows. - Norwegian institute of
seaweed research. Report no. 32, 35 pp.
Kaufmann W., Hagemeister, H . & Dirksen, G .
1979. Adaptation to changes in dietary comppsition, level and frequency of feeding. - In: Rucke¬
bush, Y . & Thivend, P. Eds. Digestive Physiology
and Metabolism in ruminants. Proc. 5th. Int. Symp.
Ruminant Physiol.
Lenvik, D . & Fjellheim, P. 1977. Fordøyelsesforsøk
med lav og urea til rein. - Forskning og forsøk i
landbruket. 28: 243-253.
Mathiesen, S. D., Rognmo, A. & Blix, A. S. 1984.
A test of the usefulness of a commercially available mill «waste product» (AB-84) as feed for
starving reindeer. - Rangifer 4: 28-34.
Bøe, U . B. 1989. Utilization of grass silage by sheep:
Effects of supplementation with different amounts
of ground barley. - Norw. J. Agric. Sci. in press.
Nordfeldt, S., Cagell, W. & Nordkvist, M . 1961.
Smaltbarhetsforsok med renar, Ojebyn 1957-60. Statens husdjurforsok, Kungl. Lantbrukshogskolan,
Uppsala. Sdrtryck, Forhandsmedd. 151: 1-14.
Bøe, U . B., Gundersen, N . , Sletten, H . & Jacobsen, E . 1982. Foropptak, p H og melkesyre i vomma hos rein under overgangsforing med kraftfor
tilsatt buffer og fett. - Rangifer 2: 31-38.
Sletten, H . 1989. Erfaringer ved bruk av RF-80 i
praktisk foring. - Reindriftsnytt 23: 10-11.
Culberson, C. F. 1969. Chemical and botanical guide
to lichen products, 85-86. - University of N o r t h
Carolina Press, N C , U S A .
Ørskov, E . R. 1982. Rumen microorganisms and
their nutrition - Protein nutrition in ruminants.
19-39. Academic Press, London.
Hoover, W. H . 1986. Chemical factors involved in
ruminal fiber digestion. - /. Dairy Sci. 69: 2755¬
2766.
Åhman, B. & Åhman, G . 1980. Overgang från vinter bete til kraftfoder utfordring av ren. - Sveriges
Lantbruksuniversitet. 76. 65 pp.
SAS. SAS Users Guide 1985. Statistics, 5th ed.: 433¬
506. SAS Institute Inc. N o r t h Carolina, U S A .
M a n u s c r i p t d e l i v e r e d 11 N o v e m b e r ,
Rangifer, 1 (10),
1990
1989
37