We almost all use alfalfa in one form or another on our farms, and we all want the best quality we can get to feed our animals. How does the way alfalfa is harvested affect this? According to a research study conducted by the University of Minnesota, hay raking has a direct correlation to the content on ash in the alfalfa our animals are fed.
What is ash? Ash is the total mineral content of the forage, and occurs in one of two forms. Internal ash content is associated with naturally occurring minerals such as nitrogen, potassium, calcium, and phosphorus, and external ash is associated with soil contamination. This internal ash content has no negative effects on hay efficiency, however the external ash content is where the hay efficiency will start to cut into your costs. While it is not necessarily negative for your animals in small amounts, higher content can mean decreased nutrient efficiency of the alfalfa, and can negatively affect your feed costs. Since ash does not provide any nutritional value, alfalfa that contains more than 8 percent dry matter may cause an economic loss as the animal will have to eat more hay to get the same nutrients.
The research study took place in several states, Minnesota, Wisconsin, and Pennsylvania. The study was testing four different types of hay rakes, and their contribution to ash content in the alfalfa. They tested first and second cutting alfalfa, and used a merger, rotary rake, and wheel rake at each of the research sites. They took data on overall alfalfa nutrition such as crude protein, neutral detergent fiber, and digestibility. There was minimum to no change in the alfalfa nutrition content with the different harvesting options. They found that the hay-rake had the most effect on the alfalfa, with the highest ash content post-raking coming from the wheel-rake. While the hay-rake still had the highest content of ash, other harvesting variables affect it as well. Some of these can vary from ground speed and even height adjustments on the rake. Some of the reasoning behind this is that the wheel-rake method takes more soil contamination and distributes it into the alfalfa itself. It is overall easier to increase the ash content due to the way the wheel-rake is designed.
What can be done with this information? In harvesting to decrease the total ash content, cutting wide swaths with flat mower knives, and also making use of a hay merger can all minimize soil contamination. Utilizing these techniques will increase the nutrition in the hay, and can increase hey efficiency by decreasing ash. This will in turn economize the hay purchased or harvested, and save money in the long run.
Link to the original research summary below:
file:///C:/Users/Sarah/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/HayRakeAsh.pdf
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