Does Sun Bleaching Cause Protein Loss in Lucerne Hay?
Does Sun Bleaching Cause Protein Loss in Lucerne Hay?
Lucerne (alfalfa) hay is a high-quality forage, prized for its protein content, digestibility, and palatability. When storing or feeding hay, many horse owners notice a pale, sun-bleached appearance and may perhaps wonder: “Has my hay lost protein?” Let’s break down what happens.
What Causes Sun Bleaching?
Sun bleaching occurs when hay is exposed to sunlight during curing, storage, or in the paddock. The ultraviolet (UV) rays from the sun break down chlorophyll, giving hay a lighter colour. This change mostly affects the appearance, not the nutritional quality.
Does Colour Affect Protein?
While hay that is bleached may look less appealing, colour alone is not a reliable indicator of protein loss. The protein content in lucerne is largely determined by:
- Stage of maturity at harvest – Younger, leafy lucerne has higher protein.
- Leaf retention – Leaves contain most of the protein; loss of leaves (from handling or weather) reduces protein.
- Storage conditions – Wet or mouldy hay can degrade protein, but dry, sun-bleached hay usually retains most of its nutrients.
Research shows that sunlight exposure mainly affects vitamins, such as carotene (Vitamin A precursor), while the protein fraction remains relatively stable.
What to Look for in Lucerne Hay
When evaluating hay quality, don’t rely on colour alone. Instead, consider:
- Leafiness: More leaves = higher protein and energy.
- Smell: Pleasant, sweet aroma indicates good quality.
- Moisture: Hay should be dry and free from mould.
- Lab testing: The most reliable way to know protein content is via nutritional analysis.
Key Takeaway
Sun-bleached lucerne hay is not automatically low in protein. While it may look pale, it can still be highly nutritious. Focus on leaf content, storage, and smell rather than colour alone. For absolute certainty, a feed analysis is the best way to determine protein levels.
