"牛羊营养不良症" can be translated into English as "malnutrition syndrome in cattle and sheep" or "nutritional deficiency disorder in cattle and sheep".
"Malnutrition syndrome" emphasizes the overall state of inadequate nutrition leading to a set of related symptoms.
"Nutritional deficiency disorder" highlights the specific lack of essential nutrients causing the disorder.
Both translations are accurate and can be used depending on the context and emphasis desired.