Ophthalmic examination and conjunctival bacteriologic culture results froma herd of North American bison

Objective-To establish ocular characteristics, determine nature and prevale nce of ocular lesions, and identify representative bacterial flora from the conjunctiva of North American bison (Bison bison). Design-Prospective study. Animals-63 bison; 45 males and 18 females. Procedure-Ophthalmic examinations were performed on 1 group of 38 bison in December 1997 and on a second group of 25 in March 1998. Eyes were examined with a penlight, magnification loop, and indirect ophthalmoscope. Two cult ure swabs were used to obtain samples from the inferior conjunctival sac. O ne swab was submitted for isolation of bacteria and the second was submitte d for isolation of Mycoplasma organisms. Results-15 ocular abnormalities were observed in 13 of the 63 bison. These included minor ocular discharge in 5 animals, 1 eyelid laceration, 1 perioc ular Demodex spp infection, 6 corneal abnormalities, 1 anterior synechia, a nd 1 cataract. Seventeen species of bacteria were isolated from the 63 swab s submitted for culture. The most prevalent bacteria were of the genus Baci llus (74.6%). Mycoplasma organisms were not observed. Conclusions and Clinical Relevance-Corneal abnormalities were the most freq uently identified ocular lesions in bison, Bacterial flora of the conjuncti va and ocular characteristics were similar to those reported for cattle.