Congenital bilateral clinical anophthalmia and brachygnathia superior in a fighting bull calf

This study describes a case of a 20‐day‐old male fighting bull with bilateral clinical anophthalmia and brachygnathia superior whose dam was 12.5 years old and was mistakenly dewormed with ivermectin intramuscularly in the first third of gestation in a livestock farm. A macroscopic examination of the carcass was performed, with a special focus on the ocular components. Eyeball remains were found in both orbits and a histopathological examination was performed on them. Antibodies by serological study against bovine herpes virus‐1, respiratory syncytial virus and bovine viral diarrhea virus for both the cow and the calf were not detected. The calf had small orbits and inside them a white and brown mass of soft consistency. Microscopically, abundant muscular and adipose tissue was observed, alongside nervous structures and vestiges of ocular structures with stratified epithelium and abundant connective tissue with glands. No evidence that this congenital bilateral anophthalmia had infectious or hereditary origin was found. By contrast, the malformation could be related to the treatment with ivermectin during the first month of gestation.