Economic impact of paratuberculosis in dairy cattle herds: a review

Paratuberculosis (PTB) is a disease which causes considerable economic losses to producers of livestock, particularly dairy cows. Nowadays PTB is one of the most prevailing and costly infectious diseases of dairy cattle. The purpose of the present study was to review economic losses, which may be caused by Mycobacterium avium subsp. paratuberculosis (MAP) above all in herds of dairy cattle. The most important losses caused by the presence of clinically ill animals have been thoroughly described: loss of milk production and poor body condition followed by death or culling. In contrast, losses arising from a subclinical disease have not been well documented and contradictory results have been published to date. The calculation of losses caused by PTB depends to a certain degree on the production system in a herd, efficiency level, herd management system and other factors. Direct economic losses are above all caused by decreased milk production concurrent to increased incidence of mastitis, changes in milk parameters and increased somatic cell counts, reproductive dysfunctions, poor feed conversion, shortened production age and increased predisposition to other diseases etc. Indirect economic losses are caused by premature culling of animals and their unrealized future income, expenses for non-active production, herd replacement, diagnostic testing, "unnecessary" veterinary care and establishing disease control programmes. Genetic value of animals and their progeny is lost. Last but not least, the reputation of the farm where MAP infected animals are kept is lost for a long-time, which is also important.