Search

Objetivou-se relatar dois casos clínicos de potras com 4 e 5 meses de idade da raça Mangalarga Marchador, demonstrando sinais de cegueira noturna. Os animais apresentavam histórico de desorientação no período noturno. No exame oftálmico, todos os parâmetros foram normais, exceto pela ausência de reflexo de ameaça na penumbra. A fundoscopia não demonstrou nenhuma anormalidade morfológica da retina. A eletrorretinografia confirmou falha na atividade elétrica dos bastonetes, fotorreceptores da retina responsáveis pela visão noturna. No entanto, percebeu-se também uma pequena redução da atividade elétrica dos cones, demonstrando que os animais podem ter uma dificuldade visual em ambientes claros. O exame genômico dos folículos pilosos (Veterinary Genetics Laboratory/UC – Davis, USA) não demonstrou homozigose para Complexo do Leopardo, conjunto de genes associado à cegueira noturna estacionária congênita (CSNB) em cavalos com pelagem despigmentada. A análise genealógica demonstrou um parentesco em comum entre os animais descritos. Assim, tornam-se necessárias pesquisas adicionais para determinação genômica da cegueira noturna em equinos da raça Mangalarga Marchador.

ABSTRACT. Rosa M., Botteon P.T.L., Pereira J.S., Brooks D.E. & Rosa M.V.D. Evaluation of equine electroretinographic responses by using two different electrodes and four different Alpha-2 agonist sedatives. [Avaliação da resposta eletroretinográfica de equinos utilizando dois tipos de eletrodos quatro sedativos Alfa-2 agonistas diferentes.] Revista Brasileira de Medicina Veterinária, 36(4):367-374, 2014. Centro de Pesquisa em Oftalmologia Veterinária (CEPOV), Avenida das Américas, 700, Bloco 8, Loja 103J, Barra da Tijuca, Rio de Janeiro, RJ 22640-100, Brasil. E-mail: marcmax@globo.com The aim of this study was the evaluation and comparison of field electroretinographic responses in standing horses using two different active electrodes (DTL- plus™ and ERG-jet®), and four different alpha-2 agonist drugs Xylazine, Romifidine, Detomidine, Medetomidine. Forty healthy horses were evaluated by full field ERG. Horses were randomly allocated into eight groups according four sedative drugs and two electrodes types. In all groups a- and b- wave amplitudes and implicit times were investigated and compared for both eyes. Quality and costs of sedation drugs were estimated. This research leaded to the conclusion that there were no significant differences of a- and b-wave complex results between ERG-jet® and DTL-plus™ electrodes with any sedative type. The ERG-jet® lens proved to be more practical during the examination than the DTL-plus™ electrode. The use of a single dose of xylazine, romifidine, detomidine or medetomidine was sufficient to provide a good level of sedation and muscle relaxation during the ERG examination, although detomidine and medetomidine gave slightly superior results when compared with the otherdrugs in this study. The sedation with xylazine was the least when compared with the other drugs and it was also the cheapest to use. Any of the sedatives and either active electrode tested in this study should permit a good full field ERG evaluation in standing horses.

This study aimed to evaluate the use of equine amniotic membrane (EAM), frozen indirectly using liquid nitrogen and stored between −10° and −24°C, in the treatment of equine skin lesions. Six healthy female horses, aged 3–10 years, were included in this study. EAM was collected from previously evaluated healthy parturient mares. Wounds were surgically created at the distal ends of the forelimbs. One limb was chosen for treatment, and the contralateral limb was chosen as the control. Pain sensitivity, presence of granulation tissue, secretions, and bleeding after debridement during cleaning were evaluated. Microscopically, the following were evaluated: the integrity of the epithelium, the organization of the connective tissue, the presence of hemorrhage, fibroplasia, epithelial hyperplasia, hyperkeratosis, neovascularization, and the types of cells present. Assessments were performed on days 0, 3, 7, 14, 21, 28, and 63, and the time to complete the lesion closure. Treatment with EAM promoted faster recovery, greater neovascularization, better quality fibroplasia, and less sensitivity to pain than the control group. We concluded that the use of EAM was advantageous compared to the control group.