Discriminant and multiple regression analysis of anemia and opportunistic infection in Fell pony foals

A condition resembling acquired immunodeficiency with anemia has been described in British Fell pony foals. The pathogenesis is unknown. The present study involved 322 foals of which 164 were of Fell breed and 12 were affected. Discriminant and multiple regression analyses were used to test the results of all clinical pathology parameters from these foals for statistical association with (1) breed origin and (2) presence of disease. Only hematocrit associated significantly with presence of disease. However, significant associations were found with Fell breed origin, including serum albumin concentration and lymphocyte count. The unexpected discovery of sporadic lymphocytosis in the breed indicates the value of this kind of analysis and may be evidence that Fell foal immunodeficiency is associated with retroviral infection.