A contribution for a better comprehension of donkey dentistry: a study based on the Mirandês and Zamorano-Leonés donkeys (Equus asinus)
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2014-08-25
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No Nordeste de Portugal e na zona Oeste da Província de Zamora em Espanha, os burros
desempenham um papel chave na agricultura tradicional. Estas regiões são as principais áreas
de distribuição das duas raças autóctones de burros ameaçadas, utilizadas neste estudo: o
Mirandês e o Zamorano-Leonés.
Na área da Medicina Estomatológico-dentária Veterinária, a investigação e o trabalho
clínico em cavalos evoluiu substancialmente nos últimos anos, a nível mundial, mas o
conhecimento específico destas temáticas nos burros continua de algum modo num patamar
inferior.
A obtenção de dados científicos nesta ou noutras áreas do conhecimento, relativamente a
estas raças ameaçadas, é tida pelo autor como uma ferramenta extremamente importante
numa estratégia mais ampla de conservação in situ. Com base neste princípio, realizou-se um
estudo clínico com o objetivo de investigar a prevalência da patologia estomatológicodentária,
através da observação de 800 burros (400 de cada uma das raças referidas), divididos
em 7 grupos etários (idades compreendidas entre os 0 e os 34 anos), em 86 localidades, com
um especial enfoque no bem-estar animal e na preservação dos recursos genéticos.
Em 74% dos animais observados foram diagnosticadas situações patológicas relacionadas
com os dentes incisivos, de entre as quais o autor salienta as más-oclusões dentárias
(49,25%), irregularidades na superfície de oclusão (21,63%), fraturas (17%), doença
periodontal (16,13%) e presença de diastemas (14,38%) como sendo as principais situações
patológicas diagnosticadas.
Relativamente aos dentes pré-molares e molares (PM/M), 82,75% dos burros
apresentavam alterações, das quais as mais relevantes incluem cristas de esmalte (73,13%),
sobre-crescimentos localizados (37,25%), doença periodontal (23,50%) e presença de
diastemas (19,88%).
Diagnosticaram-se também situações patológicas consideradas pouco frequentes: presença
de dentes supranumerários, litíase do conduto salivar e o desenvolvimento macroscópico de
hiperplasia gengival focal.
Define-se poliodontia como a presença de um número excessivo de peças dentárias em
relação à fórmula dentária da espécie. Esta patologia foi diagnosticada em 2,25 % dos burros,
com 36 dentes supranumerários presentes: 2,80% referente a incisivos e 97,20% referentes a
PM/M. A localização mais comum de supranumerários é a porção mais caudal da linha de
PM/M maxilares (distomolares). O aumento da prevalência de dentes supranumerários
completamente erupcionados registada nos grupos etários mais velhos sugere uma erupção
tardia destes dentes pelo que, mesmo em burros com revisões estomatológico-dentárias
frequentes, a presença de peças dentárias supranumerárias e até então não diagnosticadas deve
ser sempre metodicamente investigada.
Diagnosticou-se litíase do conduto salivar num único burro, com base no exame clínico,
oral e radiográfico, com o sialólito localizado no conduto parotídeo direito. A remoção
cirúrgica do sialólito realizou-se através de um acesso percutâneo.
Noutro burro, observou-se uma tumefação maxilar do lado direito da face. Os exames extra
e intra oral revelaram um bloqueio completo do movimento mandibular à direita, devido
principalmente à presença de boca em tesoura, e a presença de uma massa no espaço
vestibular maxilar direito. A hiperplasia gengival a nível histológico é considerada normal. A
uma escala macroscópica, a proliferação gengival é considerada patológica e associada a
processos inflamatórios, neoplásicos e não neoplásicos, incluindo a hiperplasia gengival. Em
equídeos, estas lesões são pouco frequentes, devendo no entanto incluir a lista de diagnósticos
diferenciais em casos de tumefação facial, principalmente quando patologia dental grave
como a boca em tesoura é diagnosticada.
A elevada prevalência de más-oclusões dentárias motivou o autor a investigar a
caracterização da base genética desta patologia. Pesquisaram-se variações genéticas do gene
Matrilin-1, utilizando 30 burros com prognatismo, 30 com braquignatismo e 30 com
ortoclusão, num estudo de caso-controlo. Identificou-se e caracterizou-se uma variação
genética (g.503G>A) localizada na região intrónica do Matrilin-1. Observaram-se diferenças
significativas entre o grupo de controlo e os casos de prognatismo. Estes resultados suportam
evidências do importante papel do Matrilin-1 na origem do prognatismo na população
analisada, com a variação genética Matrilin-1- 503G>A- apresentando um efeito protetor.
A influência do tratamento dentário na resposta aos testes de pressão, aparência fecal,
condição corporal e digestibilidade aparente da matéria seca foi também estudada. Dezoito
burros Zamorano-Leoneses foram divididos em 2 grupos homogéneos (controlo e tratamento)
tendo em conta a idade, condição corporal e patologia estomatológico-dentária. Nos dias 1,
45, 90 e 135 do estudo avaliou-se a condição corporal e a resposta aos testes de pressão em
todos os animais recolhendo-se também fezes da ampola rectal, durante 3 dias consecutivos.
Observou-se um decréscimo progressivo da resposta positiva aos testes de pressão, no grupo de tratamento. Não se observaram diferenças entre grupos para a condição corporal. Na
digestibilidade aparente da matéria seca, observaram-se diferenças em relação à data da
colheita, com uma interação entre os grupos e a data de colheita. Não se observaram
diferenças entre grupos e/ou data de colheita, em relação à aparência fecal.
Os resultados obtidos durante este estudo destacam a importância dos cuidados
estomatológico-dentários regulares em burros, mas também chamam a atenção para a
importância da realização de estudos similares em populações de equídeos com estatuto de
conservação semelhante, de modo a poder compreender-se a prevalência da patologia
estomatológico-dentária, melhorando o bem-estar destes animais e preservando recursos
genéticos únicos no mundo.
In the Northeast of Portugal and in the West of the Zamora Province in Spain, donkeys are still playing a central role in the traditional farming system. These regions are the main distribution area of the two endangered breeds of donkeys involved in the present study: the Mirandês and the Zamorano-Leonés. In veterinary dentistry, research and clinical work in horses progressed substantially worldwide in the last years, but specific knowledge regarding donkey dentistry is still somewhat behind. The acquisition of evidence-based scientific knowledge in dentistry or any other area based on these breeds is taken by the author as a powerful tool in an in situ conservation strategy. Thus, a study to investigate the prevalence of oral and dental disorders was performed, through a prospective cross-sectional study in 800 donkeys (400 of each breed), divided in 7 age groups (ranging 0-34 years), in 86 villages, thinking on welfare and genetic preservation issues. The 74% of donkeys suffer from incisors disorders: craniofacial abnormalities (49.25%), abnormalities in the occlusal surface (21.63%), fractures (17%), periodontal disease (16.13%) and diastemata (14.38%) were the main disorders recorded. Regarding cheek teeth (CT), the 82.75% of donkeys were diagnosed with disorders: CT enamel overgrowths (73.13%), focal overgrowths (37.25%), periodontal disease (23.50%) and diastemata (19.88%) were the main disorders recorded. Some uncommon pathological conditions were diagnosed, such as the presence of supernumerary teeth, salivary duct lithiasis and development of macroscopic focal gingival hyperplasia. Polyodontia is defined as the presence of teeth in excess of the normal dental formula. Polyodontia was recorded in 2.25% of the donkeys, presenting 36 supernumerary teeth, with 2.80% being incisors and 97.20% CT. The caudal aspects of the maxillary CT rows were the most common locations for supernumerary teeth development (distomolars). The increasing prevalence of fully erupted supernumerary teeth recorded in older groups suggested a late eruption, and therefore in donkeys undergoing regular dental prophylaxis the presence of previously unnoticed supernumerary teeth should always be methodically sought. One single donkey was diagnosed with salivary duct lithiasis in the right parotid duct based on clinical, oral, dental and radiographic examination results. Surgical removal of the sialolith was done through a percutaneous approach. One donkey was observed with a right maxillary tumefaction. An extra and intra-oral examination was performed, revealing a complete blockage of the right mandible motion, mainly due to the presence of shear mouth. A mass was observed in the right maxillary vestibular space. Gingival hyperplasia is a very common histological feature in equids. On a macroscopic level, pathological proliferation of the gingival tissue is associated with inflammatory, neoplastic and tumor-like masses, including gingival hyperplasia. In equids, these lesions are uncommon, but still should be considered in the differential diagnoses list for facial tumefaction, mainly when severe dental disorders such as shear mouth are diagnosed. The high prevalence of craniofacial abnormalities recorded during this study led the author to contribute to the genetic characterization of these disorders. Genetic variations in Matrilin- 1 gene were sought, using 30 donkeys presenting brachygnathism, 30 donkeys presenting prognathism and 30 donkeys with normal occlusion phenotypes, in a case-control study. One genetic variation (g.503G>A) located in an intronic region of Matrilin-1 gene was characterized. Statistically significant differences were detected between the control group and prognathism cases. These results support evidence for an important role of Matrilin-1 on prognathism in the analyzed population with Matrilin-1 genetic variation - 503G>A - having a protective effect. The influence of dental correction on nociceptive test response, fecal appearance, body condition score (BCS) and apparent dry matter digestibility (DMDap) was also studied in donkeys. Eighteen Zamorano-Leonés donkeys were divided into two homogeneous groups based on age, BCS and dental findings: control and treatment. On day 1, day 45, day 90 and day 135, BCS and nociceptive test response were evaluated in all animals and fecal samples were collected by grab sampling from all animals for 3 consecutive days. A progressive decrease of positive nociceptive test responses was observed, in treatment group. No differences between groups were observed for BCS. Concerning DMDap there were differences regarding collection day and an interaction between groups and collection day was observed. About fecal appearance, no differences were observed between groups and/or collection day. The results obtained during this study highlighted the importance of regular dental care in donkeys, but also draws attention to the importance of similar studies in equids populations with the same status conservation, in order to better understand the prevalence of oral and dental disorders, improving their welfare and preserving a unique genetic heritage.
In the Northeast of Portugal and in the West of the Zamora Province in Spain, donkeys are still playing a central role in the traditional farming system. These regions are the main distribution area of the two endangered breeds of donkeys involved in the present study: the Mirandês and the Zamorano-Leonés. In veterinary dentistry, research and clinical work in horses progressed substantially worldwide in the last years, but specific knowledge regarding donkey dentistry is still somewhat behind. The acquisition of evidence-based scientific knowledge in dentistry or any other area based on these breeds is taken by the author as a powerful tool in an in situ conservation strategy. Thus, a study to investigate the prevalence of oral and dental disorders was performed, through a prospective cross-sectional study in 800 donkeys (400 of each breed), divided in 7 age groups (ranging 0-34 years), in 86 villages, thinking on welfare and genetic preservation issues. The 74% of donkeys suffer from incisors disorders: craniofacial abnormalities (49.25%), abnormalities in the occlusal surface (21.63%), fractures (17%), periodontal disease (16.13%) and diastemata (14.38%) were the main disorders recorded. Regarding cheek teeth (CT), the 82.75% of donkeys were diagnosed with disorders: CT enamel overgrowths (73.13%), focal overgrowths (37.25%), periodontal disease (23.50%) and diastemata (19.88%) were the main disorders recorded. Some uncommon pathological conditions were diagnosed, such as the presence of supernumerary teeth, salivary duct lithiasis and development of macroscopic focal gingival hyperplasia. Polyodontia is defined as the presence of teeth in excess of the normal dental formula. Polyodontia was recorded in 2.25% of the donkeys, presenting 36 supernumerary teeth, with 2.80% being incisors and 97.20% CT. The caudal aspects of the maxillary CT rows were the most common locations for supernumerary teeth development (distomolars). The increasing prevalence of fully erupted supernumerary teeth recorded in older groups suggested a late eruption, and therefore in donkeys undergoing regular dental prophylaxis the presence of previously unnoticed supernumerary teeth should always be methodically sought. One single donkey was diagnosed with salivary duct lithiasis in the right parotid duct based on clinical, oral, dental and radiographic examination results. Surgical removal of the sialolith was done through a percutaneous approach. One donkey was observed with a right maxillary tumefaction. An extra and intra-oral examination was performed, revealing a complete blockage of the right mandible motion, mainly due to the presence of shear mouth. A mass was observed in the right maxillary vestibular space. Gingival hyperplasia is a very common histological feature in equids. On a macroscopic level, pathological proliferation of the gingival tissue is associated with inflammatory, neoplastic and tumor-like masses, including gingival hyperplasia. In equids, these lesions are uncommon, but still should be considered in the differential diagnoses list for facial tumefaction, mainly when severe dental disorders such as shear mouth are diagnosed. The high prevalence of craniofacial abnormalities recorded during this study led the author to contribute to the genetic characterization of these disorders. Genetic variations in Matrilin- 1 gene were sought, using 30 donkeys presenting brachygnathism, 30 donkeys presenting prognathism and 30 donkeys with normal occlusion phenotypes, in a case-control study. One genetic variation (g.503G>A) located in an intronic region of Matrilin-1 gene was characterized. Statistically significant differences were detected between the control group and prognathism cases. These results support evidence for an important role of Matrilin-1 on prognathism in the analyzed population with Matrilin-1 genetic variation - 503G>A - having a protective effect. The influence of dental correction on nociceptive test response, fecal appearance, body condition score (BCS) and apparent dry matter digestibility (DMDap) was also studied in donkeys. Eighteen Zamorano-Leonés donkeys were divided into two homogeneous groups based on age, BCS and dental findings: control and treatment. On day 1, day 45, day 90 and day 135, BCS and nociceptive test response were evaluated in all animals and fecal samples were collected by grab sampling from all animals for 3 consecutive days. A progressive decrease of positive nociceptive test responses was observed, in treatment group. No differences between groups were observed for BCS. Concerning DMDap there were differences regarding collection day and an interaction between groups and collection day was observed. About fecal appearance, no differences were observed between groups and/or collection day. The results obtained during this study highlighted the importance of regular dental care in donkeys, but also draws attention to the importance of similar studies in equids populations with the same status conservation, in order to better understand the prevalence of oral and dental disorders, improving their welfare and preserving a unique genetic heritage.
Descrição
Tese de Doutoramento em Ciências Veterinárias
Palavras-chave
Burro (Mirandês, Zamorano-Leonés) , Odontologia veterinária , Doenças estomatognáticas , Bem-estar animal , Medicina estomatológico-dentária veterinária