Impact of parasitism in goat production

Abstract

Goats can be infected by protozoan or metazoan parasites, in internal infections or external infestations, in certain predilection organs or found at various sites. Parasitism leads to depletion of resources of affected animals, as well as, in many cases, in decreased feed intake, resulting in reduced production. These production constraints are particularly important in many tropical or subtropical areas, where goats play an essential role in the agricultural economy. The present paper summarises the potential impact of parasitism in the production of goats and discusses specific examples of adverse effects in the various facets of goat production. Animals with highest milk yield have particularly significantly decrease in milk production in cases of parasitic infections, but no changes in milk composition. In relation to effects of gastrointestinal parasitism in goat-kids, it has been found that growth rate of kids increased and carcasses produced were of better quality after administration of effective anthelmintic drug. Various parasitic infections adversely affect reproductive efficiency in herds; for example, genital myiosis would cause lesions impeding mating, scrotal sarcoptic mange can lead to reduction of testicular mass and besnoitosis may affect the testes, whilst protozoa have a foetopathic effect, causing abortions and/or stillbirths, and long-term reduction of reproductive output in affected does, as well as infecting young kids, causing increased neonatal mortality. Finally, the various ectoparasites affecting goats (e.g., Mallophaga lice or Przhevalskiana silenus) cause severe damage on the skin of affected animals, which would render their hair unsuitable for processing or would reduce its value.