Why you'll want to avoid this flawed feed.
I’ve been trying to work with some wet alfalfa haylage on one of my client’s dairies. It was harvested wetter than normal on the advice of an inoculant supplier but ended up very wet at 75% moisture.
There are many potential undesirable consequences of wet haylage fermentation:
1. Excessive dry matter and nutrient losses. The excessive seepage was the first evidence of losses in this particular haylage. Not only are a lot of nutrients washed away, but dealing with the effluent is a stinky headache.
2. Wet haylage can result in a clostridial fermentation, which can produce excessive butyric acid and breakdown proteins to ammonia and amines. Clostridium bacteria can cause digestive problems and have been implicated as a cause of hemorrhagic bowel syndrome. In addition, high butyric acid reduces palatability and intake and can increase the risk of ketosis because it is a precursor of beta-hydroxybutyrate (BHBA), a ketone. This particular haylage had the unmistakable putrid smell caused by the protein breakdown products.
3. Haylages that are high in butyric acid (> 0.5% of dry matter) are usually low in lactic acid (< 6% of dry matter) and not very stable when exposed to air or mixed in a TMR.
4. High acetic acid levels (> 4% of dry matter) can result from wet haylage fermentation. High acetic acid can also reduce intake. However, inoculants containing Lactobacillus buchneri , designed to help aerobic stability, also contain higher acetic acid but have not been shown to reduce intake. Some researchers have speculated that the intake reduction of animals fed silage with high acetic acid may be due to other unidentified factors associated with poor fermentation. This particular haylage was 5.5% acetic acid.
We were experiencing lower intakes with this haylage. Stuck with having to feed it up, we replaced a substantial portion of the haylage with dry hay, and intakes have improved. To avoid these problems, alfalfa haylage should be put up at least 30% dry matter.