Flieg-Index — Application in Fodder Quality Evaluation

Correct Answer: Silage quality

The Flieg-index is a widely used scoring method to evaluate silage quality. It is calculated from the proportions of organic acids (lactic acid, acetic acid, butyric acid) and ammoniacal nitrogen in silage, giving a numerical index.

Silage Quality Classification (from notes)

• Very good: pH 3.5–4.2, NH₃-N < 10%, Butyric acid = nil
• Good: pH 4.2–4.5, NH₃-N = 10–15%, Butyric acid = trace
• Fair: pH > 4.8, NH₃-N > 20%, Butyric acid = some

Silage Making Key Facts

• Chief acid produced: Lactic acid
• Good silage colour: Yellowish or brownish-green
• Brown colour of silage: due to Phaeophytin (chlorophyll converted during ensiling)
• Brown colour of HAY: due to Maillard reaction