Corneal sensitivity in five horse breeds

EnglishThis study aimed to determine and compare corneal sensitivity values in different regions of the cornea in five horse breeds. One hundred and forty five healthy horses, adults of both sexes, of the following breeds - Arabian horse (AH; n=20), Mangalarga Marchador (MM; n=50), Pure Blood Lusitano (PBL; n=35), Quarter Horse (QH; n=20), Brazilian Sport Horse (BSH; n=20)-were investigated. Corneal touch threshold (CTT) was measured with a Cochet-Bonnet esthesiometer in five different corneal regions. Measurements of the median central CTT were: 4.50±0.50cm (AH), 3.50±0.56cm (MM), 3.00±0.25cm (PBL), 2.50±0.44cm (QH) and 2.50±0.00cm (BSH). The central region was the most sensitive and the dorsal region the least sensitive corneal region for all breeds. CTT values differed for corneal regions and horse breeds. The CTT values were different among the corneal regions and the horse breeds. Arabian horses presented higher sensitivity values being the most sensitive in all of the corneal regions. Key words: Arabian horse; Equus caballus; Cochet-Bonnet; corneal touch threshold portuguesObjetivou-se com o presente estudo, determinar e comparar valores de sensibilidade corneana em diferentes regioes da cornea em cinco racas de equinos. Foram investigados 145 equinos higidos, adultos de ambos os sexos, das racas: Puro Sangue Arabe (PSA; n=20), Mangalarga Marchador (MM; n=50), Puro Sangue Lusitano (PBL; n=35), Quarto de Milha (QH; n=20) e Brasileiro de Hipismo (BSH; n=20). O limiar tactil da cornea (LTC) foi mensurado com o auxilio do estesiometro de Cochet-Bonnet, em cinco diferentes regioes da cornea (central, nasal, ventral, temporal e dorsal). Os valores medios das mensuracoes do LTC central foram: 4,50±0,50cm (PSA), 3,50±0,56cm (MM), 3,00±0,25cm (PSL), 2,50±0,44cm (QM) e 2,50±0,00cm (BH). A regiao central foi a mais sensivel e a regiao dorsal a menos sensivel para todas as racas. Os valores de LTC diferiram para as regioes da cornea e entre as racas dos cavalos, sendo a raca Puro Sangue Arabe o que apresentou valores maiores de sensibilidade, desta forma sendo o mais sensivel em todas as regioes corneanas. Palavras-chave: Puro Sangue Arabe; Eqqus caballus; Cochet-Bonnet; limiar tactil corneano