Pre-slaughter handling of reindeer bulls { Rangifer tarandus tarandus L . ) — effects on technological and sensory meat quality , blood metabolites and muscular and abomasal lesions

Forty-one reindeer bulls (age 1 1/2 years) were subjected to different pre-slaughter treatments: herding for a short distance to a grazing corral, selection by use of a lasso, lorry transport and helicopter herding for 1, 2 and 3 days respectively. As control, 9 reindeer were shot without previous handling (in the mountains). The results indicated the traditional selection technique of using a lasso to be the most stressful and glycogen-depleting handling procedure so far studied. In the lasso-selected reindeer the lowest glycogen values and the highest ultimate pH values in the meat were measured. The values of the measured parameters indicating stress (aspartate aminotransferase (ASAT), urea, Cortisol and abomasal lesions) were also highest in these reindeer. By contrast, the modern method of herding by helicopter was not found to be detrimental to glycogen content, ultimate pH, the measured blood metabolites, or the frequency of abomasal lesions. In all treatment groups degenerative lesions were observed in the skeletal muscles. No relarionship between technological and sensory meat quality characteristics and skeletal muscle lesions in reindeer could, however, be found in this study. The study confirmed an earlier finding that a 'stress-flavour' could develop in reindeer meat after intensive pre-slaughter handling of the animals. Further study of when and how such "stress-flavour" develops ought to be undertaken.


Material and methods
The study was performed in Mellanbyn, a Saami community close to Giillivare in the northern part of Sweden.A total of 41 reindeer bulls (age 1 l li years) were subjected to 7 different pre-slaughter treatments (Table 1).
Reindeer in groups A, E, F and G were shot in the head using a rifle (calibre 308 Winchester), while reindeer in the other groups were stunned with a captive bolt.From reindeer in groups A, E, F and G (shot in the mountains), blood and muscle samples were taken directly in the field, and the carcasses The abomasal mucosa from all reindeer was investigated for the presence of mucosal lesions and haemorrhages and rated on a scale from 0 (not affected) to 4 (severe lesions).

Glycogen determination in muscle samples
Muscle samples were freeze-dried for 24 h whereafter connective tissue, fat and blood were removed under a dissection microscope.Glycogen was analysed by assessing glucose residues after 1-2 mg of tissue had been boiled for 2 h in 1 M HC1 (Lowry & Passoneau, 1973).

Blood metabolites
Plasma samples were analysed for aspartate amino-

Sensory evaluation
The saddle (the part of the back which is cut out between vertebrae thoracales 6-7 and vertebrae lumbales 110 Rangifer, 16 (3), 1996 Shot in the head with a rifle.
1 Alter exclusion of one animal, see Matenal and methods.applied a descriptive test (Stone & Sidel, 1985;Piggott, 1988).The questionnaire was formulated with special reference to reindeer meat.The definitions of the profile attributes are described in Table 2, and the panel scored the sensory attributes on a continuous intensity scale ranging from 0 (low intensity) to 9 (high intensity).

Ill
Table 2. Definitions of the sensory attributes used in the sensory profiling of the reindeer meat.

Attribute Definition
Intensity of odour Intensity of any odour in the product.
Liver odour Odour of liver, metallic.

Pungent odour
Strong and intense odour sensation.

Whiteness
Colour measured on a newly cut slice of meat, black or pure colour to white colour.

Hue
Yellow/red to red/blue.

Intensity of colour
Colour: none -intense.

Intensity of flavour
Intensity of any flavour in the product.
Li ver flavour Flavour of liver, metallic.

Sharp flavour
Strong and intense flavour sensation.

Acidic flavour
Primary taste produced by acid (e.g.citric acid, lemon).

Juiciness
Perception of juice absorbed from the product.

Hardness
Mechanical texture attribute measured by compressing the product between the teeth, force required to produce deformation of the product.

Tenderness
Mechanical texture attribute related to cohesiveness and to the length of time or the number of chews required to masticate a solid product into a state ready for swallowing.

Statistical analyses
The statistical analysis was carried out with the Statistical Analysis System (SAS Institute Inc., 1995) using the GLM and MIXED procedures.The model for comparing pH values and glycogen content included the fixed effects of treatment group and muscle, the random effect of animal nested within treatment group, and also the interaction (treatment group x muscle).As the interaction was nonsignificant for glycogen content, the overall effect of treatment group across muscles is shown (Fig. 1).
For pH values, however, the interaction (treatment group x muscle) was significant and, for the sake of  Rangifer, 16 (3), 1996 as well as the fixed effects of treatment group, panel member and the interaction (panel member x treatment group).The interaction (panel member x treatment group) was excluded from the model when not significant.
As in earlier studies (Wiklund et al., 1995(Wiklund et al., , 1996) ) pH values were converted in the statistical analyses to hydrogen ion concentrations and when presenting mean values they were reconverted from estimates on the concentration scale.Standard errors, however, become non-symmetric and error ranges on the pH scale were therefore calculated.

Glycogen content and ultimate pH values
The different pre-slaughter handling treatments affected the glycogen concentrations in the three muscles similarly (Table 3).Mean glycogen concentrations for the three muscles are shown in Fig. 1.
Groups A (shot without previous handling) and G (herded by helicopter for 3 days) had the highest content of glycogen in Mm. longissimus dorsi, biceps femoris and triceps brachii (see Table 3).After the herding down to a grazing corral close to the slaughterhouse, a significant part of the glycogen stores had been consumed (group B), while in reindeer subjected to the lasso selection procedure (group C) and to both lasso selection and subsequent lorry transport (group D) most glycogen had been consumed.
During the helicopter herding (groups E, F, and G) the glycogen content increased significantly with longer herding times in all three muscles. Group

Blood metabolites, abomasal lesions and skeletal muscle lesions
Group C showed the highest ASAT values, otherwise there were no significant differences between the groups (Table 4).However, group D also tended to

Sensory evaluation
For sensory evaluation of the meat, groups A, B, C and G were included.Significant inter-group differences were found regarding odour, colour and flavour attributes (Table 5).Group A had a stronger odour and flavour of liver, while the sharp and sickeningly sweet odour and flavour were much less pronounced in this group than in the other groups.
Meat from reindeer in group A also had a lighter colour and tasted more acidic. 114

Discussion
The different pre-slaughter handling procedures affected the muscle glycogen stores in different ways.Whereas herding reindeer down to the grazing corral (group B) and the selection procedure (groups C and D) depleted the glycogen stores significantly, the glycogen content of all muscles studied from helicopter herded animals were much higher (groups E, F and G) (Fig. 1).These results indicate that during the helicopter herding the reindeer were actually able to build up their glycogen stores rather than them being depleted, thanks to generous access to pasture and sufficient time to graze, while the combined effect of the stress of lasso selection and lorry transport (group D) decreased the glycogen stores significantly in M. longissimus dorsi even though the animals had access to feed for 2 days.McVeigh & Tarrant (1982) showed in cattle that when young bulls were stressed and their glycogen stores became depleted, it took 7 days of rest and normal feeding to restore the glycogen stores to resting values.Our earlier studies showed that glycogen stores were not reduced when reindeer were transported by lorry for distances up to 1000 km (Wiklund et ai, 1996), whereas manual handling and restraint caused severe depletion of glycogen DFD (dark, firm, dry) meat is a well-known quality defect that shortens shelf life, especially for vacuum-packed meat and also affects meat colour, texture and water-holding properties (Tarrant & Hood, 1981).Had the official Swedish DFD limit for beef been applied, with an ultimate pH value > 6.2 in AL longissimus dorsi, A carcasses of the total of 41 (1 from group B and 3 from group C) would have been classified as DFD.The slaughter industry sometimes use a DFD limit of 5.8 in the AL longissimus dorsi for beef carcasses; in the present study the use of this limit would have classified 13 reindeer carcasses as DFD (2 from group B, 5 from group C, 4 from group D, 1 from group E and 1 from group F).
From earlier studies (Skjenneberg et al., 191 A;Petaja, 1983;Wiklund eta/., 1995) et al., 1976;Nieminen, 1980;Rehbinder & Edqvist, 1981).Wiklund et al. (19%) obtained low ASAT and urea values from reindeer in good physical condition.Cortisol values have been used as a marker for acute stress in reindeer (Rehbinder et al, 1982;Wiklund et al., 1994).The Cortisol hours caused high frequencies of abomasal lesions (Rehbinder et al, 1982;Rehbinder, 1990).From the present study, however, we can conclude from the measured values of blood metabolites and abomasal lesions that herding by helicopter was not so stressful to the reindeer that it affected the homeostasis of the animals, whereas the manual handling  Rangifer, 16 (3), 1996 and restraint of individual animals during the traditional lasso-selection procedure had a serious impact on the reindeer.

Skeletal muscle lesions have earlier been reported
in connection with stressful situations; herding and handling of reindeer (Rehbinder et al, 1982), restraint stress in pigs (Bjurstrom, 1995), capture of wild white-tailed deer (Beringer et al., 1996) and other wild ruminants (Harthoorn, 1977).In the present study, an evaluation of the extent and severity of degenerative changes was not possible, probably due to the limited sample size and number of samples obtained.Muscular lesions indistinguable from those of capture myopathy were however recorded in all treatment groups.
The present study has confirmed an earlier finding that a 'stress-flavour' could develop in reindeer meat after intensive pre-slaughter handling of the animals, as the groups selected by use of a lasso (C) and herded by helicopter for 3 days (G) had the highest values of pungent odour, sickeningly sweet odour, sharp flavour and sickeningly sweet flavour.
It is common knowledge among reindeer herdsmen that animals that have been exposed to very stressful pre-slaughter handling give meat with 'stress-flavour'.This flavour is described as unpleasant, strong -even acrid.Several studies have tried to correlate the concentrations of substances such as putrescine, spermidine, spermine, creatine, creatinine and dimethylamine in reindeer meat and plasma with the presence of 'stress-flavour' in the meat (Rehbinder & Edqvist, 1981;Hanssen et al, 1984;Rogstadkjcernet & Hanssen, 1985;Hanssen & Skei, 1990), but the issue is still unresolved.Liver flavour has been detected in cuts of beef semimembranosus muscle following injection with lactic acid and calcium chloride solutions, while non-injected cuts evidenced less of this off-flavour (Eilers et al., 1994).
All the cuts had very low pH values, similar to those in group A in the present study, where both the liver flavour and the liver odour were stronger than in all other groups.Storage of cuts for up to 17 days post mortem did not affect the intensity of liver flavour in beef (Eilers et al, 1994).
The results from the present study indicated that the traditional selection technique of using a lasso may well be the most stressful and glycogen-depleting handling procedure so far studied.By contrast, There is also a need for further research in the field of sensory quality of reindeer meat.It is of great general interest to study when and how a 'stressflavour' develops in the meat, and also to assess the effects of different feeding regimes, starvation, and extremely protracted transport on the sensory quality of reindeer meat.
The relationship between technological and sensory meat quality characteristics and skeletal muscle lesions in reindeer ought to be further investigated, concerning meat quality as well as animal welfare.
From earlier studies (Barnier, 1995;Wiklund et al, 1995) it is known that, in reindeer meat, the postmortem pH decline is rapid, which is unusual in other investigated ruminants.Further studies of the post mortem metabolism and the speed and efficiency of muscle proteolysis in reindeer meat in relation to skeletal muscle degeneration are therefore of great interest.
Most of the above-mentioned modern handling procedures expose the entire reindeer herds -or parts thereof -to a stressful situation, except for the selection procedure by which animals are removed individually from the herd.The purpose of this investigation was to study and quantify glycogen content and ultimate pH values in reindeer muscles and sensory quality of reindeer meat from animals (1) unaffected by manual or mechanical handling, (2) herded down from the mountains to a grazing corral by combined use of helicopter, snowmobiles and dogs, (3) captured in a traditional selection corral by use of the lasso, and (4) herded by helicopter for 1, 2 and 3 days respectively.Another objective was to study stress-induced blood metabolites and pathological changes in the abomasal mucosa and in three skeletal muscles (M.longissimus dorsi, M. biceps femoris and M.triceps brachii) following different handling procedures.
were then transported by helicopter to the slaughterhouse in Harra.Reindeer in groups B, C and D were stunned in the selection corral or just outside the slaughterhouse in Harra.Group D was allowed to rest for 2 days after the selection procedure before being transported by lorry 100 km to the slaughterhouse.While resting, they were offered hay and silage.One animal from group B was considered to be an outlier and was therefore excluded due to total glycogen depletion in all 3 muscles studied (4-32 mmol/kg dry weight) and high pH values (6.81¬ 6.83).Upon exsanguination, blood samples were collected in heparinized tubes, chilled, centrifuged and within 45 min after sampling, the plasma was frozen in liquid nitrogen(-196°C).Samples from M. longissimus dorsi (LD) (at the last rib), M. biceps femoris (BF) and M. triceps brachii (TB) were taken at approximately 15 min post mortem and frozen in liquid nitrogen.A piece of each muscle (1 cm 3 ) was fixed in 10% buffered formalin, embedded in paraffin, cut in 5um thick sections and stained with hae-matoxylin-eosin and PTAH (Phosphotungstic Acid Haematoxylin).The samples were investigated for the presence of muscular lesions.

5- 6 )
from each of 16 reindeer in groups A, B, C and G (4 from each group) was excised and packed in a plastic bag, kept refrigerared (at +3°C -+ 5°C) for 14 days and then frozen.The samples were then transported to Matforsk (Norwegian Food Research Institute, As, Norway) where the sensory analysis was performed.The reindeer saddles were split in two halves (right and left Al, longissimus dorsi) and sawn into chops.The panel members always received their chops from the same part of the longissimus muscle.The chops were vacuum-packed and then Rangifer, 16 (3), 1996 heated in a waterbath to + 65°C for 120 min.The sensory profile of the reindeer meat was assessed by a trained expert panel comprising 11 members, who

Fig. 1 .
Fig. 1.Glycogen content (least-squares means) after different pre-slaughcer handling of reindeer bulls when all studied muscles are taken into consideration (Mm.Itmgisumus, biceps femoris and triceps hrachii.For treatment groups and numbers investigated, seeTable 1).Means with the same lett-

(
Essen-Gustavsson & Rehbinder, 1984).The results of the present study indicate that a herd-forming animal such as the reindeer is markedly sensitive to Rangifer, 16 (3), 1996 the restraint stress associated with handling by the procedures used to remove individual animals from the herd/group.
values from the present study demonstrated the difficulties with shooting reindeer totally 'undisturbed' in the mountains, as individual animals were seriously affected by the hunting.Earlier studies demonstrated that mucosal lesions and haemorrhages in the abomasum could develop after a short period of acute stress.Stressful reindeer herding by means of helicopter in deep snow for 4 " n.s.= P>0.05; ** = P<0.01;*** = P<0.001.Within-attribute means having the same superscript are not significantly different (P>0.05).
a modern technique such as helicopter herding did not negatively affect glycogen content, ultimate pH, the values of the measured blood metabolites or the frequency of abomasal lesions.Further research 116 is definitely needed to thoroughly investigate the selection procedure and to compare the lasso technique with other selection methods.

Table 1 .
Characteristics of various treatment groups of reindeer included in the study.
A showed the lowest ultimate pH values in M. longissimus dorsi, while in M. biceps femoris and Al.triceps brachii the lowest pH values were found in groups A and G (see Table3).As a result of the

Table 3
. Glycogen content and ultimate pH value in M. longissimus.Al.biceps femoris and Al.triceps brachii (least-squares means ± standard errors') for reindeer bulls included in the study (for numbers investigated, see Table1).Least-squares means and ranges for means + standard errors were reconverted from the concentration scale.Means in the same row having the same superscript (letters) are not significantly different (P>0.05).Within-crait means in the same column having the same superscript (numbers) are not significantly different (P>0.05).Rangifer,16 (3), 1996 11.3 Table 4. Blood metabolites and abomasal lesions (least-squares means + standard errors) in reindeer bulls included in the srudy (for numbers investigated, see Table1) and the degree of significance for the effect of treatment group.producehighvalues.The urea values showed significant differences between groups, as groups A, E, F and G had low values and group C had the highest.The Cortisol values were low in groups E, F and G,

Table 5 -
Sensory evaluation scores for meat (Al.longissimus) (least-squares means and standard errors) from reindeer bulls in groups A, B, C and G included in the study and the degree of significance for the effect of treatment group,