A criação de ovinos e caprinos depende de um manejo eficiente, devido, principalmente, ao prejuízo causado por parasitos em animais susceptíveis. Vários fatores colaboram para que os animais tolerem as infecções parasitárias, como: genética, nutrição, estado fisiológico e idade. O grave problema causado pela resistência anti-helmíntica promoveu a difusão de técnicas alternativas de controle parasitário. Dentre essas novas estratégias incluem-se a adoção do tratamento parcial seletivo com o método FAMACHA, fitoterapia, controle biológico com o uso de fungos nematófagos e estratégias que ainda necessitam de mais dados como a homeopatia, a diluição da resistência com a introdução de parasitos sensíveis e a combinação de produtos químicos sem efeito antiparasitário. O objetivo central destes métodos é reduzir o uso de antiparasitários, retardando o desenvolvimento da resistência, e promover melhor utilização de produtos ainda eficazes na propriedade e de novos produtos que venham a ser lançados. Este artigo abordará as técnicas descritas acima para o controle de nematoides de pequenos ruminantes e é direcionado aos técnicos interessados em ampliar seu conhecimento sobre os mecanismos de resistência dos parasitos aos anti-helmínticos e de alternativas ao uso desses produtos.

Sheep and goat farming requires an efficient management program, due to losses caused by parasites in susceptible animals. Many factors may collaborate to improve infection tolerance in the herd, such as: genetics, nutrition, physiological status, and age. The problem caused by resistance to antihelmintic agents has led to the spread of alternative techniques for parasite controls. The latest strategies include selective treatment with the FAMACHA method, phytotherapy, biological control with predatory fungi, and strategies that still await scientific confirmation, such as homeopathy, the dilution of resistance with the introduction of susceptible parasites, and the combination of drugs without antihelmintic effect. The main objective of these methods is to reduce the usage of antiparasitic agents, thus slowing the development of resistance and promoting the better use of effective products and newly released products. The objective of this article is to describe techniques for controlling nematodes in small ruminants, and it is aimed at technicians interested in increasing their knowledge about the mechanisms of resistance to antihelmintic agents as well as alternatives to the use of these products.

In three trials conducted on two separate farms the production of sheep treated for naturally acquired haemonchosis using the FAMACHA© system of targeted selective treatment (TST) (i.e. to treat only those animals unable to manage unaided in the face of heavy Haemonchus challenge) was compared to that of suppressively drenched sheep in the same flock. As expected by the research team who developed and evaluated the FAMACHA© system, TST did result in some loss in production. However, despite high levels of worm challenge in two of the trials and the fact that the comparison was with suppressive drenching which is not sustainable, the total effect was relatively small in relation to the important advantage of using the TST as regards reduced selection for anthelmintic resistance (AR). Concerning the sustainability of worm control, it is concluded that the development of drug resistance to anthelmintics leaves sheep and goat farmers in South Africa no choice but to use methods of TST such as FAMACHA©. The FAMACHA© system can also be a useful clinical aid for early on-farm detection of AR by farmers; the degree of improvement in the colour of the ocular mucous membrane from pale to red in individually drenched anaemic animals over a period of 7-14 days can give a good indication of the efficacy of the compound(s) used.