Este artículo se focaliza en las variaciones del contenido de proteína de un campo natural frente a distintos escenarios de nivel hídrico, composición y estructura de la pastura y agregado de fertilizantes al suelo.

ABSTRACT.- Macrocyclic lactones are widely used as endectocides in farm animals. Intoxications occur in situations of overdose and/or malnutrition, in young animals, and in genetically sensitive breeds. We describe the intoxication by doramectin in malnourished 15-month-old cattle that received 1.6 times the recommended dose. The animals presented salivation, ataxia, motor incoordination, reluctance to move, and sternal recumbency. Two animals recovered spontaneously; one died and was necropsied. No gross or microscopic changes were observed.