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Aust Vet J Vol 76, No 10, October 1998 693 Pre-euthanasia sedation for dogs and cats O verpopulation of dogs and cats has lead to a situation where, in the USA alone, millions of unwanted or feral animals are killed yearly. Mass euthanasia is stressful for the animals and not without risks for the workers. Researchers from the University of Tennessee examined five oral drug regimens for dogs and four regimens for cats, in order to find a safe, humane and affordable option for pre-euthanasia sedation. The drugs for dogs, acepromazine, tiletamine-zolazepam, the combination of tiletamine-zolazepam and acepro- mazine, the combination of tiletamine-zolazepam and butorphanol, and pentobarbital sodium, were selected from available oral sedatives. There were six to eight healthy dogs of different ages, breeds and sexes in each group. Food was withheld for 12 h before dosing. Only dogs that ate all the food, in which the capsules or tablets were mixed, were included in the study. None of the regimens effected a perfect sedation. The onset and depth of sedation was variable. Acepromazine and tiletamine-zolazepam doses may have been too small. Pentobarbital sodium at 63 mg/kg caused a deep seda- tion in six of seven dogs. One of these dogs thrashed while on sedation. The drug showed promise as an inexpen- sive and relatively reliable sedative, although combining it with acepromazine may be warranted to avoid side effects. The combination of tiletamine-zolazepam and acepromazine also caused a good sedation, but the regimen was more expensive. The cats were sedated by squirting an injectable drug into their mouths when they were hissing. Four regimens were examined: detomidine, ketamine and two mixtures of detomidine and ketamine. Each regimen was tested with nine cats. Detomidine, an equine α-2 adrenergic sedative was used because it is effective when used orally, unlike other α-2 adrenergic compounds. As expected, about a third of the cats that received detomidine vomited. The combination of 0.5 mg/kg detomidine and 10 mg/kg ketamine was the most consistent regimen, causing lateral recumbency and good relaxation in all cats in this group. Ramsay EC, Wetzel RW. Comparison of five regimens for oral administration of medication to induce sedation in dogs prior to euthanasia. J Am Vet Med Assoc 1998;213:240-242. Wetzel RW, Ramsay EC. Comparison of four regimens for intraoral administration of medication to induce sedation in cats prior to euthanasia. J Am Vet Med Assoc 1998;213:243-245. Discussion The feral cats’ diet consisted of mammals, birds, reptiles and insects. In comparison, the domestic cats’ diet consisted of commercially available canned and dry food. As the majority of cats had calculus present and the diets differed markedly, we suggest that diet may play a part in the prevalence of calculus but is not the sole contributing factor in periodontal disease in the cat. Other factors such as breed, age, chewing behaviour and systemic health may have a considerable influence on the preva- lence of periodontal disease. The severity of periodontal disease in the feral cats contradicts the claims of the importance of the texture of the natural diet in preventing periodontal disease. Although the mean calculus scores were significantly different between feral and domestic cats, the prevalence of periodontal disease was not. The presence of alveolar bone loss, missing canine teeth, osteomyelitis and thickened alveolar bone estab- lishes that feral cats suffer from periodontal disease, despite eating an abrasive diet. There was no association found between the type of diet consumed and the prevalence of periodontal disease in the 49 cats studied, but there was an association found between the type of diet eaten and calculus formation. This study suggests that the texture of the diet of feral cats does not prevent them from acquiring dental calculus, does not protect them against periodontal disease and that commercially available canned and dry foods have not been the sole cause, nor increased the prevalence of periodontal disease in the domestic cat. Acknowledgments The authors would like to thank Dr Robert Maillardet for advise on statistical analysis. The Pet Food Industry Association of Australia Inc provided financial support which is gratefully acknowledged. References 1. Maretta SM. Current concepts in canine and feline dentistry. In: Current veterinary therapy XII. Saunders, Philadelphia, 1994:685-691. 2. Crossley DA. Survey of feline dental problems encountered in a small animal practice in NW England. Brit Vet Dent Assoc J 1991;2:2. 3. Page RC, Shroeder HE. Periodontitis in man and other animals. A compara- tive review. Karger, Basel, 1982. 4. Lindhe J, Rylander H. Experimental gingivitis in young dogs. Scand J Dent Res 1975;83:314-326. 5. Linde J, Hamp S, Loe H. Plaque induced periodontal disease in beagle dogs. A 4 year clinical, roentgenographical and histometrical study. J Periodontal Res 1987;58:706-713. 6. Rugg-Gunn AJ. Nutrition and periodontal disease. In: Nutrition and dental health. Oxford University Press, London 1993:304-321. 7. Watson ADJ. Diet and periodontal disease in dogs and cats. Aust Vet J 1994;71:313-318. 8. Lonsdale T. Periodontal disease and leucopenia. J Small Anim Pract. 1995;36:542-546. 9. Pet food produces lively AGM [news item]. AVA News, June 1993:1,9. 10. Higgins P. Preventative dentistry. In: Teeth - open wide. University of Sydney Post Graduate Committee in Veterinary Science, 1987;100:181-184. 11. Harvey CE. Optimizing oral health: diet and periodontal disease. Vet Forum September 1993:52-53. (Accepted for publication 20 July 1998)

Pre-euthanasia sedation for dogs and cats

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Page 1: Pre-euthanasia sedation for dogs and cats

Aust Vet J Vol 76, No 10, October 1998 693

Pre-euthanasia sedation for dogs and cats

Overpopulation of dogs and cats has lead to a situation where, in the USA alone, millions of unwanted or feralanimals are killed yearly. Mass euthanasia is stressful for the animals and not without risks for the workers.

Researchers from the University of Tennessee examined five oral drug regimens for dogs and four regimens for cats,in order to find a safe, humane and affordable option for pre-euthanasia sedation.

The drugs for dogs, acepromazine, tiletamine-zolazepam, the combination of tiletamine-zolazepam and acepro-mazine, the combination of tiletamine-zolazepam and butorphanol, and pentobarbital sodium, were selected fromavailable oral sedatives. There were six to eight healthy dogs of different ages, breeds and sexes in each group.Food was withheld for 12 h before dosing. Only dogs that ate all the food, in which the capsules or tablets weremixed, were included in the study.

None of the regimens effected a perfect sedation. The onset and depth of sedation was variable. Acepromazineand tiletamine-zolazepam doses may have been too small. Pentobarbital sodium at 63 mg/kg caused a deep seda-tion in six of seven dogs. One of these dogs thrashed while on sedation. The drug showed promise as an inexpen-sive and relatively reliable sedative, although combining it with acepromazine may be warranted to avoid sideeffects. The combination of tiletamine-zolazepam and acepromazine also caused a good sedation, but the regimenwas more expensive.

The cats were sedated by squirting an injectable drug into their mouths when they were hissing. Four regimenswere examined: detomidine, ketamine and two mixtures of detomidine and ketamine. Each regimen was tested withnine cats. Detomidine, an equine α-2 adrenergic sedative was used because it is effective when used orally, unlikeother α-2 adrenergic compounds.

As expected, about a third of the cats that received detomidine vomited. The combination of 0.5 mg/kg detomidineand 10 mg/kg ketamine was the most consistent regimen, causing lateral recumbency and good relaxation in all catsin this group. Ramsay EC, Wetzel RW. Comparison of five regimens for oral administration of medication to induce sedation in dogs prior toeuthanasia. J Am Vet Med Assoc 1998;213:240-242.Wetzel RW, Ramsay EC. Comparison of four regimens for intraoral administration of medication to induce sedation in cats prior toeuthanasia. J Am Vet Med Assoc 1998;213:243-245.

DiscussionThe feral cats’ diet consisted of mammals, birds, reptiles and

insects. In comparison, the domestic cats’ diet consisted ofcommercially available canned and dry food. As the majority ofcats had calculus present and the diets differed markedly, wesuggest that diet may play a part in the prevalence of calculusbut is not the sole contributing factor in periodontal disease inthe cat. Other factors such as breed, age, chewing behaviour andsystemic health may have a considerable influence on the preva-lence of periodontal disease. The severity of periodontal diseasein the feral cats contradicts the claims of the importance of thetexture of the natural diet in preventing periodontal disease.

Although the mean calculus scores were significantly differentbetween feral and domestic cats, the prevalence of periodontaldisease was not. The presence of alveolar bone loss, missingcanine teeth, osteomyelitis and thickened alveolar bone estab-lishes that feral cats suffer from periodontal disease, despiteeating an abrasive diet. There was no association found betweenthe type of diet consumed and the prevalence of periodontaldisease in the 49 cats studied, but there was an associationfound between the type of diet eaten and calculus formation.

This study suggests that the texture of the diet of feral catsdoes not prevent them from acquiring dental calculus, does notprotect them against periodontal disease and that commerciallyavailable canned and dry foods have not been the sole cause, norincreased the prevalence of periodontal disease in the domesticcat.

AcknowledgmentsThe authors would like to thank Dr Robert Maillardet for

advise on statistical analysis. The Pet Food Industry Associationof Australia Inc provided financial support which is gratefullyacknowledged.

References1. Maretta SM. Current concepts in canine and feline dentistry. In: Currentveterinary therapy XII. Saunders, Philadelphia, 1994:685-691.2. Crossley DA. Survey of feline dental problems encountered in a small animalpractice in NW England. Brit Vet Dent Assoc J 1991;2:2.3. Page RC, Shroeder HE. Periodontitis in man and other animals. A compara-tive review. Karger, Basel, 1982.4. Lindhe J, Rylander H. Experimental gingivitis in young dogs. Scand J DentRes 1975;83:314-326.5. Linde J, Hamp S, Loe H. Plaque induced periodontal disease in beagle dogs.A 4 year clinical, roentgenographical and histometrical study. J Periodontal Res1987;58:706-713.6. Rugg-Gunn AJ. Nutrition and periodontal disease. In: Nutrition and dentalhealth. Oxford University Press, London 1993:304-321.7. Watson ADJ. Diet and periodontal disease in dogs and cats. Aust Vet J1994;71:313-318.8. Lonsdale T. Periodontal disease and leucopenia. J Small Anim Pract.1995;36:542-546.9. Pet food produces lively AGM [news item]. AVA News, June 1993:1,9.10. Higgins P. Preventative dentistry. In: Teeth - open wide. University ofSydney Post Graduate Committee in Veterinary Science, 1987;100:181-184.11. Harvey CE. Optimizing oral health: diet and periodontal disease. Vet ForumSeptember 1993:52-53.

(Accepted for publication 20 July 1998)