Epizootiology of gastrointestinal strongyles in Pelibuey ewes in a silvopastoral system under a selective treatment program

Abstract

When used separately, anti-parasitic efficacy of nutrient (MP) supplementation and bioactive forage consumption is usually considerably lower than what can be achieved through the use of pharmaceuticals, although it has been argued that the latter may not necessarily be required nor desired. It might be therefore beneficial to combine these strategies to control parasites to a greater extent than possible when they are used in isolation. This is because nutrient supplementation and PSM consumption affect differently components of parasite life cycle (epidemiology) and benefit hosts differently at different productive stages (e.g. growing vs. lactating small ruminants). This principle has just been applied in temperate systems of production with greatly promising consequences. The strategy used was the supplementation of ewes with MP and the supply of chicory as forage to their lambs, and resulted in substantially reducing the antiparasitic drug input into the system than was achieved by using either of the two strategies on its own. The issue is whether the principles developed above could be applied to control parasites in small ruminant systems of production in the tropics, especially because the option of nutrient supplementation might not always be available. When devising such nutritional strategies one should take into account the availability of local resources on the one hand and both the antiparasitic and anti-nutritional properties of local forages on the other. Only then alternative strategies can be implemented and incorporated into local systems of production with a high degree of success. The final part of this paper will concentrate on this issue.