Paratuberculosis in Chilean dairy goat herds

Abstract

Paratuberculosis in goats is widely distributed throughout the world. Recently the disease has been officially reported in Chile. The purpose of this study was to determine the infection status of some dairy goat herds under two types of management systems (intensive and extensive) in different regions of Chile. Faecal samples were collected from 383 female goats > 2 years old belonging to 8 dairy goat herds located in the Metropolitan Region (2), 9^th Region (5) and 10^th Region (1). Differences in routine management were not considered when selecting the herds. Faecal samples were collected via rectum, decontaminated with hexadecylpyridinium chloride (HPC) and antibiotics, cultured on Herrolds Egg Yolk Medium with mycobactin J, and incubated at 37ºC for up to nine months. The suspected colonies were confirmed by PCR (IS900) technology using specific primers for this pathogen (P90+ and P91+). Thirty five out of the 383 sampled goats were faecal culture positive (9.1%), all of them belonging to only four herds. These infected herds were generally larger, intensively managed, and they systematically violated most management recommendations for paratuberculosis control, including the routine introduction of animals of unknown paratuberculosis tests status from herds of unknown Map infection status. The remaining four uninfected herds were extensively managed, did not import goats from other herds, and were located in geographical areas where no mixed grazing with other susceptible ruminant species took place, this being a possible risk factor for paratuberculosis. This study reports the presence of caprine paratuberculosis in Chile, in particular in those dairy goat herds that have introduced high producing milk breeds of animals to improve the genetic capacity of milk production. Therefore, any attempt to evaluate the risk of introducing the infection in a paratuberculosisfree area as the result of purchasing animals is worthwhile.