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The Immobilization of the Badger (Meles Meles)
Br. vet.]. ( 1976) 132, 6og
THE IMMOBILIZATION OF THE BADGER (MELES MELES) BY C. G. MACKINTOSH,*
J. A. MAcARTHUR,t T. W. A. LITTLE* AND P. STUART*
*Central Veterinary Laboratory, Weybridge, Surrey Potters Bar, Herts
t Universities Federation for Animal Welfare, SUMMARY
The development of a safe method for the tranquillization and immobilization of the badger, (Meles meles) is described. Over a period of 8 months, 3I badgers were immobilized on I 46 occasions using one of the following agents: etorphine hydrochloride with methotrimeprazine; halothane; ketamine hydrochloride and acepromazine. Ketamine hydrochloride was found to be the most satisfactory agent for the safe immobilization of wild badgers in captivity. INTRODUCTION The discovery of tuberculosis infection in the badger (Meles meles), associated with a high rate of reactions to the tuberculin test amongst cattle in parts of Gloucestershire (Muirhead, Gallagher & Burn, I974), made it necessary to detect and study the disease in live badgers and a colony of badgers was established for this purpose. In the course of the work, the badgers had to be handled so that simple procedures such as weighing, tuberculin testing, blood sampling and removal of faecal samples could be carried out. Good tranquillization and immobilization was therefore necessary. An effective immobilizing agent for use in wild animals should ideally be: (i) quick acting; (i) easy to administer; (iii) have a wide safety margin and (iv) have a short recovery time. Phencyclidine, phenothiazine tranquillizers and succinylcholine are the only agents described in the literature for use in badgers (Balser, I 965; Seal & Erickson, I 969; Bailey, I 97 I ; Fitzgerald, I 973). The first two of these agents have long recovery times while the third has a narrow safety range and its use has been reported to result in some fatalities (Fitzgerald, I973). Consequently, they were considered unsuitable for use in this experiment. This paper describes the development of a safe method of immobilizing badgers based on experience at the Central Veterinary Laboratory (CVL) with various agents. MATERIALS AND METHODS Over a period of eight months, 3 I badgers were immobilized on I 46 occasions using four agents: etorphine hydrochloride with methotrimeprazine and its
610
BRITISH VETERINARY JOURNAL, 132, 6
specific antagonist diprenorphine (ImmobilonJRevivon Small Animal: Reckitt & Colman Ltd., Pharmaceutical Division, Hull); ketamine hydrochloride (Vetalar ( 100 mgjml): Parke, Davis & Co., Usk Road, Pontypool, Gwent, NP4 8YH); acepromazine maleate (Acetylpromazine (ro mgjml): C-Vet Ltd., Braintree, Essex) and halothane (Fluothane: ICI Ltd., Alderley Park, Macclesfield, Cheshire). The first three drugs were administered by intramuscular injection into the rump or the back of the hind leg. The animal was held in a box 45 em X 6o em X 45 em deep with a hinged lid and an open end over which a metal grille was placed once the badger had been shepherded inside. A smaller grille was used to hold the animal firmly against the inside of the box to control movement while the injection was being given. Either 2 ml or 5 ml disposable syringes were used with 23 G X 2·5 em needles. Dosages were usually based on known body weights. When Immobilon was used, an equivalent volume of Revivon was given intravenously as soon as the sampling procedure was completed, or earlier if the animals appeared to have been overdosed. A number of animals required a repeat injection of ketamine to produce complete immobilization and the total dose injected is recorded in Table I. When used in combination, ketamine and acepromazine were given simultaneously in the same syringe. Halothane was administered using a simple Boyle's vaporizer delivering a maximum concentration with an oxygen flow rate of ro ljmin through a flexible tube to a plastic cone-shaped face mask 12·5 em long with 7 em diameter orifice. The badger was held in a box as described above and a mask was gently placed over the face. In a few cases the mask was not tolerated and on these occasions the box was placed in a plastic bag and halothane vapour was passed in at maximum concentration. After 3 or 4 minutes the badger was sufficiently relaxed to allow direct masking. For maintenance the flow rate was reduced to 3 ljrnin.
RESULTS AND DISCUSSION
The drugs used, their average doses and range of doses, immobilization time and recovery times are given in Table I for 143 of the total 146 occasions of badger immobilization. Three fatalities occurred whilst using Immobilon and the details are described in the text and are not represented in the Table. Immobilization time was defined as the period from administration of the drug until such time as the animal could be handled safely. When the initial injection failed to produce immobilization, the time was measured from the effective injection. In the case of halothane it represented the induction period. It was difficult to assess accurately a point of recovery from which to compare the agents used as they all had very different characteristics. It was originally decided to use ImmobilonJRevivon, as this combination was known to be satisfactory in dogs and had been used extensively in wild and zoo animals (Harthoorn, 1971 and 1973; Alford, Berkhart & Johnson, 1974).
TABLE I RESULTS OF IMMOBILIZING WILD BADGERS (MELES MELES) IN CAPTIVITY
No. of occasions Average dose and range (mg/kg) Immobilization time (min) Recovery: R egain mobility (min) Complete recovery (min)
Etorphine/ methotrimeprazine
Halothane
14*
61
57
0•014 (o·OI 1- 0·017)
Maximum cone. from Boyle's apparatus
19·25 (9·5-31·ot)
2-5
2-7
10-15
3-6
2-5
49 (26-120)
Never completely immobilized
43 (gs- 6o)
30
90-180
300-540
300-360
4-6
Ketamine
* 3 badgers that died not represented here.
Ketamine /acepromazine
6 4 1·2 (o·86-x ·s8) Ketamine 14·9 (w·6-21 ·9t)
+
A.C.P. o·37 (o·2 1-o·53)
With diprenorphine i.v. 5 60- 120
Acepromazine
...... ~ ~
0
t:ll ...... t"' ......
N
> t-::1 ...... 0
z 0
'-.:!
~
t:t:l
~ ;; ::0
t the higher dose rate included a repeated injection.
"'
~
612
BRITISH VETERINARY JOURNAL,
132,
6
Etorphine at a dosage rate of o·o14 mg/kg body weight (approximately double the recommended dose rate for dogs) was used successfully on 14 occasions, producing immobilization in about 5 min and, although the animals were sensitive to noise, they remained recumbent. The degree of relaxation varied from fair to good. There was usually some respiratory depression and, as soon as the sampling was completed, the anaesthesia was reversed with an intravenous injection of Revivon, which produced a rapid initial recovery within 5 min, followed by a residual one to two hour period of slight narcosis and tranquillization. However, at this dose rate of o·014 mgfkg, two badgers stopped breathing and, despite intravenous Revivon and artificial resuscitation, died shortly after. One of these animals had just completed a journey in a transport box, but the other was clinically normal and had responded well to exactly the same dose on a previous occasion. A third badger received a higher dose rate of o·o37 mgfkg, but the injection was probably subcutaneous as the animal was not completely anaesthetized and could move around the pen. It was given Revivon intramuscularly, made an apparent recovery, but was found dead six hours later. Post-mortem examination of all three fatal cases showed no macroscopic lesions. Respiratory depression with etorphine had been reported as a problem in Bovidae, Equidae and Ursidae (Alford et al., 1974). Since a mortality rate of3 in 17 was considered unsatisfactory, other means of immobilizing the badgers were sought. Halothane was used on the next 61 occasions and provided satisfactory anaesthesia. Relaxation was good, the depth could be varied to suit the procedure and there were no deaths. However, the apparatus was cumbersome, fractious animals were difficult to handle, the technique was expensive and, in inexperienced hands, could be dangerous. For these reasons a trial using ketamine hydrochloride was performed. This agent, which is chemically related to phencyclidine, has been used extensively in domestic cats and dogs as well as wild and zoo animals (De Young, Paddleford & Short, I 972; Kaplan, I 972; Glen, I 973; Harthoorn, I 973). The recommended dose rate for intramuscular injection in most animals is Io-25 mgfkg (De Young et al., I 972; Harthoorn, I 973; Smuts, Bryden, Vos & Young, I 973) but there is no information on its use in badgers. A dose rate of Io-2o mgfkg was tried and found to be satisfactory for immobilization on 49 occasions, although the muscle relaxation was poor in I5 of these. It was found that, in a further eight cases, there was little or no effect following the initial injection and a second injection was given which was, in all cases, effective. These apparent failures were always associated with injections into the rump where there is a thick layer of subcutaneous fat. Injections into the back of the thigh, though more awkward, gave better relaxation and deeper anaesthesia, apparently due to more rapid absorption of the drug. Ketamine produces a state known as dissociative anaesthesia which, at 20 mgfkg, was characterized by immobilization and recumbency within 5 min. There was usually an initial period of apnoea and mild salivation while the corneal and laryngeal reflexes were maintained throughout the anaesthesia. The maximum degree of relaxation and anaesthesia occurred from 8 to 20 min
IMMOBILIZATION OF THE BADGER
613
after the injection and respiratory movements during this period were characteristically fast and shallow with an occasional gasp. The animals regained the use of their forelegs in 4o-45 min and their hindlegs in 45-55 min after injection. Initially during recovery they were ataxic and hyperaesthetic but were aware of their surroundings and sought seclusion. Recovery was usually complete in I !-2 hours. This picture could be modified by altering the dose rate. At IoI 5 mg/kg the anaesthesia was lighter and of shorter duration, there was less relaxation, the animals started recovering after 25-30 min and the period of a taxia was shorter. Conversely, with a higher dose the relaxation was greater, anaesthesia was of longer duration and the period of ataxia and depression lasted up to 3 hours after injection. There was, however, some individual variation; on two occasions one apparently normal badger took I 20 and 8o minutes to regain mobility after doses of 28 and I9 mg/kg respectively. In our experience, ketamine appeared to have a wide margin of safety. It has been used safely on badgers, some of which were subsequently shown to have advanced tuberculosis. One badger, which is not recorded on Table I, received a trial dose of 54 mg/kg and after an initial period of apnoea made a prolonged but uneventful recovery. Doses as high as IOO mgfkg have been used safely in the mink for major surgery (MacLeod, personal communication) and in the cat the manufacturers recommend up to 50 mg/kg. No deaths occurred with ketamine nor any vomiting or convulsions. No drug adaptation was experienced after dosing badgers on five occasions and the subsequent appetite of these animals was unaffected. A small trial was conducted on the use of acepromazine, both by itself and in conjunction with ketamine. At I ·o-I ·5 mg/kg acepromazine alone produced a profound tranquillization in about IO min which was adequate for manual restraint and minor procedures. These animals showed no aggression or fear and were bled and tuberculin-tested without difficulty although they could still move if placed on the ground. They remained heavily tranquillized for 3-4 hours and had recovered fully in 6-7 hours. This prolonged tranquillization might be useful in the field but was unnecessary in our work. When used in combination, the dose rates of both drugs could be lowered: ketamine at Io-I5 mg/kg and acepromazine at o·2-o·5 mg/kg gave adequate immobilization and relaxation. After the initial recovery from ketamine the animals again remained quite heavily tranquillized for up to 6 hours.
CONCLUSION From these experiments we concluded that: I. ketamine was the most satisfactory agent for immobilizing wild badgers in captivity and is now being used routinely; 2. acepromazine gave prolonged tranquillization, but not true immobilization; 3· halothane provided good anaesthesia but was inconvenient to use; 4· etorphine caused marked respiratory depression and was considered unsuitable in the badger.
BRITISH VETERINARY JOURNAL, 132, 6 ACKNOWLEDGMENTS
Thanks are due toP. F. Naylor and W. R. Eastlake for practical assistance, and to Miss E. Hurst and Mrs J. A. Lee for typing the manuscript. REFERENCES
ALFORD, B. T., Bu RKHART, R . L. &joHNSON, W. P. (1974). ]. Am. vet. med. Ass. 164.702. BAILEY, T. N. (1971). ]. Wildt. Mgmt, 35, 847. BALSER, D. S. ( 1965). ]. Wildt. Mgmt, 29. 438. DE YouNG, D. W., PADDLEFORD, R. R. & SHORT, C. E. (1972). J. Am. vet. med. Ass. 161, 1442. FITZGERALD, P. F. (1973). J. Wildt. Mgmt, 37,418. GLEN,j. B. (1973). Vet. Rec. 92, 65. HARTHOORN, A. M. ( 1971 ). XIX Congr. mundial de med. vet. Zoot. 2, 509. HARTHOORN, A.M. (1973). In The Capture and Care of Wild Animals, ed. Young, E. Cape Town and Pretoria: Human and Rousseau. KAPLAN, B. (1972). Vet. Med.fSm. Anim. Clin. 67,631. MUIRHEAD, R. H. , GALLAGHER,]. & BuRN, K . J. (1 974). Vet. Rec. 9S. 552. S~AL, U.S. & ERICKSON, A. W. ( 1969) . Fed. Proc. Fedn Am. Socs. exp. Biol. 28, 1410. SMuTS, G. L., BRYDEN, B. R., Vos, V. DE & YouNG, E. (1973). Lammergeyer, 18, 1. (Accepiedjor publication 23 October 1975)
THE IMMOBILIZATION OF THE BADGER (MELES MELES) BY C. G. MACKINTOSH,*
J. A. MAcARTHUR,t T. W. A. LITTLE* AND P. STUART*
*Central Veterinary Laboratory, Weybridge, Surrey Potters Bar, Herts
t Universities Federation for Animal Welfare, SUMMARY
The development of a safe method for the tranquillization and immobilization of the badger, (Meles meles) is described. Over a period of 8 months, 3I badgers were immobilized on I 46 occasions using one of the following agents: etorphine hydrochloride with methotrimeprazine; halothane; ketamine hydrochloride and acepromazine. Ketamine hydrochloride was found to be the most satisfactory agent for the safe immobilization of wild badgers in captivity. INTRODUCTION The discovery of tuberculosis infection in the badger (Meles meles), associated with a high rate of reactions to the tuberculin test amongst cattle in parts of Gloucestershire (Muirhead, Gallagher & Burn, I974), made it necessary to detect and study the disease in live badgers and a colony of badgers was established for this purpose. In the course of the work, the badgers had to be handled so that simple procedures such as weighing, tuberculin testing, blood sampling and removal of faecal samples could be carried out. Good tranquillization and immobilization was therefore necessary. An effective immobilizing agent for use in wild animals should ideally be: (i) quick acting; (i) easy to administer; (iii) have a wide safety margin and (iv) have a short recovery time. Phencyclidine, phenothiazine tranquillizers and succinylcholine are the only agents described in the literature for use in badgers (Balser, I 965; Seal & Erickson, I 969; Bailey, I 97 I ; Fitzgerald, I 973). The first two of these agents have long recovery times while the third has a narrow safety range and its use has been reported to result in some fatalities (Fitzgerald, I973). Consequently, they were considered unsuitable for use in this experiment. This paper describes the development of a safe method of immobilizing badgers based on experience at the Central Veterinary Laboratory (CVL) with various agents. MATERIALS AND METHODS Over a period of eight months, 3 I badgers were immobilized on I 46 occasions using four agents: etorphine hydrochloride with methotrimeprazine and its
610
BRITISH VETERINARY JOURNAL, 132, 6
specific antagonist diprenorphine (ImmobilonJRevivon Small Animal: Reckitt & Colman Ltd., Pharmaceutical Division, Hull); ketamine hydrochloride (Vetalar ( 100 mgjml): Parke, Davis & Co., Usk Road, Pontypool, Gwent, NP4 8YH); acepromazine maleate (Acetylpromazine (ro mgjml): C-Vet Ltd., Braintree, Essex) and halothane (Fluothane: ICI Ltd., Alderley Park, Macclesfield, Cheshire). The first three drugs were administered by intramuscular injection into the rump or the back of the hind leg. The animal was held in a box 45 em X 6o em X 45 em deep with a hinged lid and an open end over which a metal grille was placed once the badger had been shepherded inside. A smaller grille was used to hold the animal firmly against the inside of the box to control movement while the injection was being given. Either 2 ml or 5 ml disposable syringes were used with 23 G X 2·5 em needles. Dosages were usually based on known body weights. When Immobilon was used, an equivalent volume of Revivon was given intravenously as soon as the sampling procedure was completed, or earlier if the animals appeared to have been overdosed. A number of animals required a repeat injection of ketamine to produce complete immobilization and the total dose injected is recorded in Table I. When used in combination, ketamine and acepromazine were given simultaneously in the same syringe. Halothane was administered using a simple Boyle's vaporizer delivering a maximum concentration with an oxygen flow rate of ro ljmin through a flexible tube to a plastic cone-shaped face mask 12·5 em long with 7 em diameter orifice. The badger was held in a box as described above and a mask was gently placed over the face. In a few cases the mask was not tolerated and on these occasions the box was placed in a plastic bag and halothane vapour was passed in at maximum concentration. After 3 or 4 minutes the badger was sufficiently relaxed to allow direct masking. For maintenance the flow rate was reduced to 3 ljrnin.
RESULTS AND DISCUSSION
The drugs used, their average doses and range of doses, immobilization time and recovery times are given in Table I for 143 of the total 146 occasions of badger immobilization. Three fatalities occurred whilst using Immobilon and the details are described in the text and are not represented in the Table. Immobilization time was defined as the period from administration of the drug until such time as the animal could be handled safely. When the initial injection failed to produce immobilization, the time was measured from the effective injection. In the case of halothane it represented the induction period. It was difficult to assess accurately a point of recovery from which to compare the agents used as they all had very different characteristics. It was originally decided to use ImmobilonJRevivon, as this combination was known to be satisfactory in dogs and had been used extensively in wild and zoo animals (Harthoorn, 1971 and 1973; Alford, Berkhart & Johnson, 1974).
TABLE I RESULTS OF IMMOBILIZING WILD BADGERS (MELES MELES) IN CAPTIVITY
No. of occasions Average dose and range (mg/kg) Immobilization time (min) Recovery: R egain mobility (min) Complete recovery (min)
Etorphine/ methotrimeprazine
Halothane
14*
61
57
0•014 (o·OI 1- 0·017)
Maximum cone. from Boyle's apparatus
19·25 (9·5-31·ot)
2-5
2-7
10-15
3-6
2-5
49 (26-120)
Never completely immobilized
43 (gs- 6o)
30
90-180
300-540
300-360
4-6
Ketamine
* 3 badgers that died not represented here.
Ketamine /acepromazine
6 4 1·2 (o·86-x ·s8) Ketamine 14·9 (w·6-21 ·9t)
+
A.C.P. o·37 (o·2 1-o·53)
With diprenorphine i.v. 5 60- 120
Acepromazine
...... ~ ~
0
t:ll ...... t"' ......
N
> t-::1 ...... 0
z 0
'-.:!
~
t:t:l
~ ;; ::0
t the higher dose rate included a repeated injection.
"'
~
612
BRITISH VETERINARY JOURNAL,
132,
6
Etorphine at a dosage rate of o·o14 mg/kg body weight (approximately double the recommended dose rate for dogs) was used successfully on 14 occasions, producing immobilization in about 5 min and, although the animals were sensitive to noise, they remained recumbent. The degree of relaxation varied from fair to good. There was usually some respiratory depression and, as soon as the sampling was completed, the anaesthesia was reversed with an intravenous injection of Revivon, which produced a rapid initial recovery within 5 min, followed by a residual one to two hour period of slight narcosis and tranquillization. However, at this dose rate of o·014 mgfkg, two badgers stopped breathing and, despite intravenous Revivon and artificial resuscitation, died shortly after. One of these animals had just completed a journey in a transport box, but the other was clinically normal and had responded well to exactly the same dose on a previous occasion. A third badger received a higher dose rate of o·o37 mgfkg, but the injection was probably subcutaneous as the animal was not completely anaesthetized and could move around the pen. It was given Revivon intramuscularly, made an apparent recovery, but was found dead six hours later. Post-mortem examination of all three fatal cases showed no macroscopic lesions. Respiratory depression with etorphine had been reported as a problem in Bovidae, Equidae and Ursidae (Alford et al., 1974). Since a mortality rate of3 in 17 was considered unsatisfactory, other means of immobilizing the badgers were sought. Halothane was used on the next 61 occasions and provided satisfactory anaesthesia. Relaxation was good, the depth could be varied to suit the procedure and there were no deaths. However, the apparatus was cumbersome, fractious animals were difficult to handle, the technique was expensive and, in inexperienced hands, could be dangerous. For these reasons a trial using ketamine hydrochloride was performed. This agent, which is chemically related to phencyclidine, has been used extensively in domestic cats and dogs as well as wild and zoo animals (De Young, Paddleford & Short, I 972; Kaplan, I 972; Glen, I 973; Harthoorn, I 973). The recommended dose rate for intramuscular injection in most animals is Io-25 mgfkg (De Young et al., I 972; Harthoorn, I 973; Smuts, Bryden, Vos & Young, I 973) but there is no information on its use in badgers. A dose rate of Io-2o mgfkg was tried and found to be satisfactory for immobilization on 49 occasions, although the muscle relaxation was poor in I5 of these. It was found that, in a further eight cases, there was little or no effect following the initial injection and a second injection was given which was, in all cases, effective. These apparent failures were always associated with injections into the rump where there is a thick layer of subcutaneous fat. Injections into the back of the thigh, though more awkward, gave better relaxation and deeper anaesthesia, apparently due to more rapid absorption of the drug. Ketamine produces a state known as dissociative anaesthesia which, at 20 mgfkg, was characterized by immobilization and recumbency within 5 min. There was usually an initial period of apnoea and mild salivation while the corneal and laryngeal reflexes were maintained throughout the anaesthesia. The maximum degree of relaxation and anaesthesia occurred from 8 to 20 min
IMMOBILIZATION OF THE BADGER
613
after the injection and respiratory movements during this period were characteristically fast and shallow with an occasional gasp. The animals regained the use of their forelegs in 4o-45 min and their hindlegs in 45-55 min after injection. Initially during recovery they were ataxic and hyperaesthetic but were aware of their surroundings and sought seclusion. Recovery was usually complete in I !-2 hours. This picture could be modified by altering the dose rate. At IoI 5 mg/kg the anaesthesia was lighter and of shorter duration, there was less relaxation, the animals started recovering after 25-30 min and the period of a taxia was shorter. Conversely, with a higher dose the relaxation was greater, anaesthesia was of longer duration and the period of ataxia and depression lasted up to 3 hours after injection. There was, however, some individual variation; on two occasions one apparently normal badger took I 20 and 8o minutes to regain mobility after doses of 28 and I9 mg/kg respectively. In our experience, ketamine appeared to have a wide margin of safety. It has been used safely on badgers, some of which were subsequently shown to have advanced tuberculosis. One badger, which is not recorded on Table I, received a trial dose of 54 mg/kg and after an initial period of apnoea made a prolonged but uneventful recovery. Doses as high as IOO mgfkg have been used safely in the mink for major surgery (MacLeod, personal communication) and in the cat the manufacturers recommend up to 50 mg/kg. No deaths occurred with ketamine nor any vomiting or convulsions. No drug adaptation was experienced after dosing badgers on five occasions and the subsequent appetite of these animals was unaffected. A small trial was conducted on the use of acepromazine, both by itself and in conjunction with ketamine. At I ·o-I ·5 mg/kg acepromazine alone produced a profound tranquillization in about IO min which was adequate for manual restraint and minor procedures. These animals showed no aggression or fear and were bled and tuberculin-tested without difficulty although they could still move if placed on the ground. They remained heavily tranquillized for 3-4 hours and had recovered fully in 6-7 hours. This prolonged tranquillization might be useful in the field but was unnecessary in our work. When used in combination, the dose rates of both drugs could be lowered: ketamine at Io-I5 mg/kg and acepromazine at o·2-o·5 mg/kg gave adequate immobilization and relaxation. After the initial recovery from ketamine the animals again remained quite heavily tranquillized for up to 6 hours.
CONCLUSION From these experiments we concluded that: I. ketamine was the most satisfactory agent for immobilizing wild badgers in captivity and is now being used routinely; 2. acepromazine gave prolonged tranquillization, but not true immobilization; 3· halothane provided good anaesthesia but was inconvenient to use; 4· etorphine caused marked respiratory depression and was considered unsuitable in the badger.
BRITISH VETERINARY JOURNAL, 132, 6 ACKNOWLEDGMENTS
Thanks are due toP. F. Naylor and W. R. Eastlake for practical assistance, and to Miss E. Hurst and Mrs J. A. Lee for typing the manuscript. REFERENCES
ALFORD, B. T., Bu RKHART, R . L. &joHNSON, W. P. (1974). ]. Am. vet. med. Ass. 164.702. BAILEY, T. N. (1971). ]. Wildt. Mgmt, 35, 847. BALSER, D. S. ( 1965). ]. Wildt. Mgmt, 29. 438. DE YouNG, D. W., PADDLEFORD, R. R. & SHORT, C. E. (1972). J. Am. vet. med. Ass. 161, 1442. FITZGERALD, P. F. (1973). J. Wildt. Mgmt, 37,418. GLEN,j. B. (1973). Vet. Rec. 92, 65. HARTHOORN, A. M. ( 1971 ). XIX Congr. mundial de med. vet. Zoot. 2, 509. HARTHOORN, A.M. (1973). In The Capture and Care of Wild Animals, ed. Young, E. Cape Town and Pretoria: Human and Rousseau. KAPLAN, B. (1972). Vet. Med.fSm. Anim. Clin. 67,631. MUIRHEAD, R. H. , GALLAGHER,]. & BuRN, K . J. (1 974). Vet. Rec. 9S. 552. S~AL, U.S. & ERICKSON, A. W. ( 1969) . Fed. Proc. Fedn Am. Socs. exp. Biol. 28, 1410. SMuTS, G. L., BRYDEN, B. R., Vos, V. DE & YouNG, E. (1973). Lammergeyer, 18, 1. (Accepiedjor publication 23 October 1975)