INTERACTION BETWEEN NUTRITION AND GASTROINTESTINAL NEMATODES IN SMALL RUMINANTS GRAZING THE LOW DECIDUOUS FOREST - CONTRIBUTIONS FROM FMVZ-UADY

Abstract

Background. Small ruminants that graze in the low deciduous forest (LDF) face problems related to malnutrition and gastrointestinal nematode GIN infections. Over the past 30 years, FMVZ-UADY researchers have conducted extensive research to understand the interaction between small ruminant nutrition, the plants consumed in the LDF, and GINs. Objective. To review the work carried out at the FMVZ-UADY to explain why these problems of malnutrition and GIN infection occur and how to solve them. Main findings. Research shows that the complex interactions between small ruminants, the LDF plants, and the GINs help explaining malnutrition problems and GIN infections. Both of these problems have also been shown to abate through dietary supplementation, which must be designed to deliver the limiting nutrients in the LDF. Producers can use criteria such as weight gain and body condition score (BCS) to monitor that their animals are in an adequate nutritional plane of nutrition. To maintain strong resilience and resistance against GINs, growing animals should achieve >100 g / day weight gain and adults should maintain>2.5 BCS. It has also been confirmed that many LDF plant species contain secondary compounds (SC) that can affect the biology of different life stages of GIN, so they could be used as nutraceuticals. However, some SC can also adversely affect the digestion and absorption of nutrients in sheep and goats, so they must be used with caution. The presence of plants containing SC with anthelmintic activity has made it possible to explore the capacity of animals to self-medicate. In these studies, it has been shown that goats do not express a "curative" self-medication behavior against GINs, but do exhibit "preventive" self-medication behaviors that could allow them to limit their GIN burdens. However, animals seem to favor a preventive behavior aimed at avoiding nitrogen:energy imbalances in the consumed diet. Implications: Many LDF plant species have a high potential to be used for both nutritional and medicinal purposes in small ruminants, therefore, these species could be considered as nutraceutical resources. Conclusions. The work carried out in the last 3 decades has shown us that the optimal use of LDF by sheep and goats will be achieved through a better understanding of the interaction between animals, their GIN and the plants of the LDF.