Eye disorders in lesser white-fronted geese (Anser erythropus) in captivity

Sammanfattning: Eye problems are common amongst captive birds and become especially problematic in endangered species, such as the lesser white-fronted goose (LWFG). This is the case at Nordens Ark where reoccurring eye problems are seen amongst their breeding population of the species. This study aimed to describe manifestations and investigate possible causes of the eye problems seen within this population. The breeding facility of the Swedish Association of Hunting and Wildlife Management in Öster Malma Wildlife Park, collaborating closely with Nordens Ark and housing birds within the same genetic population, have not detected eye problems in their population. Site visits including keeper interviews were conducted at both facilities to determine differences that could explain the difference in eye problem prevalence. Medical records and general information of LWFG at Nordens Ark with eye problems between 2009 and 2021 were obtained from the medical records system ZIMS to describe the problem using descriptive statistics. Impact of rainfall and temperature on the number of cases per day was investigated using linear regression analysis. The implication of clutch size on the likelihood of a bird obtaining eye problems was also studied using the Chi-square test. The most common manifestations of ocular disease seen were signs of eye pain, corneal involvement, conjunctivitis, and periocular feather loss. Painful eye problems may negatively impact the welfare of the birds. Cases were almost exclusively observed between May and September and birds under two months were the most affected age group, followed by birds older than two years. No impact from rainfall or temperature on case numbers was found. Regarding management differences between Nordens Ark and Öster Malma, water provision differed most, with Nordens Ark using manually maintained plastic tubs and Öster Malma using concrete pools with constant refill and outflow of water. This, including the fact that clutch size showed a tendency of significance, rose the question if increased stocking density and its negative effects on water quality could increase the incidence of infectious eye problems. To answer this question, and to find significant evidence of the cause of the eye problems seen amongst the LWFG at Nordens Ark, further studies are needed.