Introduction
Sand is often considered a gold standard for bedding material on dairy farms and is key for maintaining cow comfort. But sand can also be a large expense for dairy farms, from new sand purchase costs to on-farm storage, labor and equipment wear. Recycling and reusing sand can significantly reduce new sand purchases but it’s important to consider a few factors before deciding to use recycled sand.
Investing in the right type of sand and equipment can set your farm up for success with recycling and reusing sand to save labor and time in the long run.
Bedding With Sand
Bedding dairy cows with sand is very beneficial for multiple reasons. Sand is an inorganic material, which means that it does not promote bacteria growth. It’s non-absorbent and moisture wicking, which means it keeps cows cleaner and drier than other bedding materials. Sand is a cool place for cows to rest in the summer and provides traction, allowing cows to get up and down more easily, therefore reducing injury to joints. Cow’s will spend up to 14 hours a day lying down and sand will cushion their body and reduce hock lesions.
Sand type selection is a critical factor when choosing to bed with sand. Different sand types will provide different levels of cow comfort and reclamation if you plan to recycle sand.
Breaking Down The Options
With a variety of sand types available, the challenge is selecting the sand that will increase cow comfort and production while maximizing operational benefits for your dairy. Your sand choice will depend on your dairy farm’s long-term goals, and if you plan to reclaim and reuse sand. Each sand type comes with different challenges, benefits and recovery potentials. Below is a chart that breaks down the different types of sand and how they compare to each other when looking at cost, unwanted packing in stalls, bacteria growth and recovery potential.
- Concrete Sand – Often characterized as ASTM C-33, this sand is the best type of sand to use as bedding material. It contains just the right mix of smaller and larger particles, which allows for proper drainage and keeping stalls dry and comfortable. Concrete sand doesn’t compact easily, compared to sands with an abundance of fine silts and clays, and it has a high recovery potential.
- Mason Sand – Mason Sand is finer than concrete sand and is more desirable to use if your manure handling goal is to pump and haul sand-laden manure rather than recover and recycle it.
- Torpedo Sand – Torpedo sand is a mix of coarse-grained sand and gravel, typically no larger than 3/8”. It is a natural sand and has good drainage.
- Silica Sand – This sand is also known as quartz sand, white sand or industrial sand. Sand will be uniform but will be more expensive than other types of sand.
- Clay or Bank Sand – Bank sand is fine-textured. It generally contains a percentage of clay and silt along with a percentage of sand. This sand is most likely excavated from the local area and may contain larger pebbles, rocks or organic material. This sand type will pack in the stalls more due to the higher clay and silt percentages.
Due to concrete sand containing minimal fine particles, it is the best type of sand for recovery in sand recycling systems. High sand recovery means less sand material to fill up holding ponds or spread on your fields, which means less money will need to be spent on new sand.
Beware of inexpensive or “free” sand. Often, this sand is dug directly from the field, which may cause it to contain pebbles that can injure cows and will be more abrasive to equipment. It can also include organic matter that can grow bacteria and become harmful to cows. Purchasing the right type of sand is just as important as a solid nutrition program.
Why Recycle Sand?
Sand bedding can be recycled for reuse after the manure has been separated out. Sand separation can reduce on-farm sand inventory and new sand purchasing. With the right type of sand and a properly designed and managed sand separation system, most farms achieve sand recovery rates above 90% and may be capturing an additional 5-8% of fine sand. When processed properly, recycled sand has no significant difference in bacteria counts and moisture compared to new sand.
In addition, mechanical sand separation lowers the cost of storage facility cleanouts, sand purchasing and labor, while keeping the sand out of fields and back under the cows where it belongs. Mechanically separated sand can be reused within 2 to 4 weeks and requires less conditioning prior to reuse, compared to several months wait time for non-mechanical separation, like a traditional sand lane or storage tanks.
Sand-laden manure creates challenges for handling, storing and processing. These challenges include increased wear and tear on equipment and sand build up in tanks, lagoons and digesters. Sand-laden manure is heavier and more abrasive than manure alone and will eventually settle out from the manure.
If you have an anaerobic digester and want to bed on sand, concrete sand is the best option because of the higher recovery rates. When using sand bedding with anaerobic digestion, as much sand as possible needs to be removed from the manure stream prior to digestion, since bypass sand can build up and cause problems with digestion equipment.
Sand recovery also carries significant economic weight. At $15 per ton, assuming 50 lbs of sand used per cow per day, recovering and recycling 90% of sand adds up to $205,313 annual savings for a 1,500-cow dairy.
Conclusion
Recycling and reusing sand can save your dairy money by reducing onsite sand storage, equipment wear and tear, sand handling and new sand purchase costs. Compared to new sand, recycled sand will provide the same benefits to cow comfort, moisture levels and inorganic matter. The correct sand type is important for maintaining cow comfort, sand that is too fine or too coarse will negatively affect cow comfort and reduce the amount of sand that you can reclaim from manure during separation.
