Sheep and goat grazing diets on an annual Mediterranean grassland containing tall wheatgrass (Thinopyrum ponticum (PODP.))

Abstract

G. Castellaro G., H. Urra A., J. Hidalgo A., C. Orellana M., and J. Escanilla C. 2018. Sheep

and goat grazing diets on an annual Mediterranean grassland containing tall wheatgrass

(Thinopyrum ponticum (PODP.)). Cienc. Inv. Agr. 45(3):240-250. The development of mixed

grazing systems is an interesting alternative for the utilization of rangelands with ecological and/

or economic limitations; therefore, the study of patterns and eating habits of different species in

the same grazing area is important. A mixed grazing study was carried out on a Mediterranean

grassland sown with Thinopyrum ponticum 30 years ago (Rinconada de Maipú, Chile 33º 28’S;

70º 51ʼ W) with the purpose of quantifying the botanical composition, dietary overlap and

selectivity indexes of the main grass species consumed by goats and sheep. Trophic behavior was

studied in seven young Suffolk Down rams, seven young Merino-Precoz rams and seven young

Boer-Criollo bucks grazing together during three grassland phenological stages. During the

grassland vegetative stage, diets were mainly composed of annual grasses and forbs. Perennial

grasses dominated the animals’ diets during the reproductive and dry grassland stages. The

diversity of the goats’ diets was higher than that of the sheep, demonstrating greater plasticity

in their dietary habits. However, in this environment, both species behaved as generalist

herbivores. The level of diet overlap between the sheep and goats was high, especially when

grazing during the grassland reproductive and dry phenological stages, suggesting potential

competition during lower forage quality stages.