The main goal of dairy cow bedding is to provide a comfortable place for the cows to lie. Ideally, cows spend much of their day — perhaps 14 hours or more — resting and ruminating, which is key for milk production. Increased lying time equals improved milk production, so cow comfort during these times of rest is imperative.
Dairy producers have many options when it comes to freestall bedding, including organic and inorganic materials. Organic materials are those such as compost, mattresses, paper, sawdust or wood shavings, and straw; inorganic materials include those such as sand.
The best bedding material is the one that maximises cow comfort and minimises the exposure of teat ends to mastitis-causing bacteria. Bedding availability may play a secondary role in bedding selection.
Sand bedding provides the ultimate in cow comfort while reducing the ability of mastitis-causing pathogens to grow and thrive.
Benefits of Sand as Dairy Cow Bedding
Sand 6-8" (15-20 cm) deep is often considered the gold standard of dairy cow bedding for several reasons. In addition to providing a comfortable place for the cows to lie, sand:
- Is an inorganic material, so it does not promote bacteria growth.
- Is non-absorbent and moisture-wicking, so it keeps cows cleaner and drier than other bedding materials.
- Provides a cool place for the cows to rest in the summer.
- Provides traction, allowing the cows to get up and down more easily and reducing injury to joints.
- Cushions the cow’s body, reducing hock lesions.
- Can be recycled for reuse (after the manure has been separated out), reducing sand inventory and purchasing.
Best Type of Sand for Bedding — Not All Sand Is Created Equally
Not all sand is appropriate for use as dairy cow bedding in freestall barns. Sand selected should be devoid of large particles that could potentially cause hoof injuries. Furthermore, bedding sand should not contain a disproportionate amount of silt or clay, which causes sand to “pack” or get hard in stalls.
The commonly recognised sand meeting these requirements is concrete sand, which is characterised by the American Standard for Testing Materials specification ASTM C-33.
Be especially wary of “free” sand that is excavated from farm fields. Field or “bank run” sand can vary widely in terms of particle size and may contain high concentrations of organic matter and bacteria. “Free” sand isn’t always free.
The above chart shows the particle size upper and lower limits for standard concrete sand. This is the preferred type of sand bedding for freestalls because it contains a range of coarse and fine particles ideal for cow comfort, stall drainage, and sand separation, recovery and reuse.
Why Concrete Sand for Freestall Bedding?
Concrete sand — also known as construction sand, torpedo sand and 2NS — is the preferred choice for sand bedding for freestalls because it does not contain particles that can harm cows and because it contains minimal fine material, so it stays loose in the stalls.
Unlike concrete sand, sand that is high in silts or clays or has an abundance of fine material can compact in the stalls, becoming a hard and uncomfortable surface for the cows to lie on. Compacted stalls require more maintenance to keep the comfort level high, so bedding with concrete sand helps minimise stall maintenance.
Because it contains minimal fine material, concrete sand readily drains away urine and, dripped milk. Sand with a lot of fine material can retain these fluids and other moisture, leading to the growth of harmful bacteria, like mastitis-causing pathogens.
Concrete sand is also ideal for sand-manure separation, again because it contains minimal fine material. With the particle size consistency of standard products like concrete sand, separation performance can be better predicted. Sand recovery is higher with concrete sand because it has less fines that could be lost during the recycling process.
Another benefit of concrete sand is that it is readily available all around the world wherever concrete is made. If a dairy can purchase concrete, they can purchase concrete sand.
Concrete sand stays loose in the stall, promotes drainage of fluids and is readily available worldwide.
Handling Sand-Laden Manure
Depending on the manure handling goals of the dairy, certain types of standard sand products are more desirable than others.
For Sand Recycling and High Sand Recovery
For example, if sand recycling and high sand recovery are your goals, concrete sand is the best option because it contains minimal fine sand.
With mechanical sand separation systems featuring equipment like Sand-Manure Separators and Agricultural Hydrocyclones, in combination with sand settling lanes, up to 98% of concrete sand can be separated, washed nearly free of organic matter and recycled for reuse.
Depending on the dairy size, recycling concrete sand can save dairy producers hundreds of thousands of dollars a year on buying new sand.
For Anaerobic Digestion
If you have an anaerobic digester and want to bed on sand, concrete sand is again the best option because it provides high sand recovery rates.
When using sand bedding with anaerobic digestion, as much sand as possible should be removed from the manure stream prior to digestion, since bypass sand can build up in and cause problems with digestion equipment.
For Pumping and Hauling
If pumping and hauling sand-laden manure is the goal, mason sand — which is finer than concrete sand, is the best choice.
And the Winner Is…
Keep in mind the basics of cow comfort. Bedding should enhance cow comfort by providing a clean comfortable resting place. Being inorganic and granular, sand meets these needs. Thanks to Mother Nature and various industrial needs, sand is available in an infinite number size gradations.
Dairy producer experience has shown concrete sand to be an ideal choice both for enhancing cow comfort and maximizing sand-manure separation system performance. Be wary of “free” sand dug out of fields. Concrete sand contains just the right mix of finer and coarser particles to meet these needs. Plus, concrete sand is available wherever concrete is sold.