Abstract
To date, there has been no detailed analysis of the death of stallions, specifically the causes and situation.Therefore a retrospective study was conducted on the deaths of 53 Japanese thoroughbred stallions from 1966 to 2010. The study found that 16 horses experienced sudden death, 13 horses died following acute abdomen due to serious intestinal damage, and 11 horses were euthanized following fatal locomotory injuries. Sudden death was recorded for four horses and three horses in January and December, respectively, and two horses in each month from March to June. Five cases of sudden death took place in paddocks, four cases in covering yards, and seven cases in stalls. Autopsies and the subsequent histopathological examinations diagnosed acute cardiac failure based on the myocardial findings such as hemorrhage, swelling, fibrosis, and infarction in seven horses, aortic root rupture in four horses, and abdominal large artery rupture in two horses. For the remaining three horses, no pathological explanation for the death could be found. Consequently, the risk of sudden death in thoroughbred stallions may increase in winter and during the open season for mating, and could mainly be associated with acute cardiovascular disorders.
