First, keep in mind the purpose of cow bedding is to provide a clean, dry and comfortable place for the lactating dairy cow. Of particular interest is minimizing teat end exposure to mastitis-causing bacteria at times when cows are particularly at risk for infection — like after milking. Second, the freestall and stall base should be a place where cows safely and confidently lay and stand, enter and exit.
Consider these five things when going to sand:
1. Stalls and stall conversions
Ideally, freestalls contain loose sand bedding that is 8” to 10” (20 to 25 cm) deep. But sand alone is not enough to compensate for poor stall design. This includes loops as well as critical dimensions: length, width, height, neck rail placement, brisket locator, etc.
If, for instance, a neck rail is improperly located toward the rear of the stall, the cow may perch in the beds and be unable to lay. If the neck rail is too far forward in the stall, the cow may lay too far forward and defecate in the stall beds, thereby negating one of the benefits of sand — that it is inorganic.
If stalls are too wide, cows may lay diagonally, causing manure and urine to be deposited in the stall beds.
Mattress stalls can successfully be converted to sand. To do this, bedding retainers can be constructed from pipes, angle iron attached to the top of the curb or plate steel attached to the vertical face of the curb. Regardless of the bedding retainer type, allow for a sand depth of 4” (10 cm).
Stalls can also be converted by demolishing the existing curb and concrete base and replacing it with new curb.
Removing a concrete stall base in preparation for sand bedding.
2. Sand selection
Not all sand is created equally, nor is “free” sand always free. The number of different sand gradations are infinite, but they are usually referred to as either fine or coarse sand.
The selection of bedding sand is most often dictated by availability and/or the intended method of manure handling. Availability is simple: an abundance of the right sand at the right price. Beware of inexpensive or “free” sand. Often, this is either sand dug directly from the field, which may cause it to contain pebbles that can injure cows or organic matter that grows bacteria. Free or cheap sand can also be a byproduct of washing construction aggregates, in which case it may contain excessive amounts of silts and clays that will pack in stalls.
Concrete sand is a commonly accepted, readily available sand. It is a standard ingredient in concrete, available wherever concrete is made, and adheres to a standard size gradation. Concrete sand contains a balance of finer and coarser particles that allow it to stay loose in the stalls, but at the same time, concrete sand allows for high recovery in sand lanes and mechanical sand separation systems.
Masons’ sand is another standard sand product and is finer than concrete sand. It is more desirable if the manure handling goal is to pump and haul sand-laden manure.
3. Filling stalls
Sand usage in freestalls is 50 pounds (23 kg) per cow per day. Sound like a lot? Not really, when you think about it. It’s a volume of sand 12” by 12” by 6” deep. Think about a cow shuffling along, entering/exiting a stall three times per day.
Filling stalls with a trailer-mounted Stall Filler.
When planning for sand bedding, remember to include a method for putting sand into stalls, which is typically done twice per week. Every four days, this equates to 200 pounds (90kg) per stall, or 10 tons per 100 cows.
To move sand in these quantities (bearing in mind the task of rebidding stalls must be accomplished in an hour or less), stalls must be filled using a high capacity Stall Filler. Stall Fillers (also known as bedding wagons or sand shooters) can be either trailer-mounted, truck-mounted, or self-propelled. In any case, choose a machine designed to withstand the weight and the abrasive nature of sand. Design barn entrances, cross-alleys, concrete thicknesses, etc. to accommodate these large, heavy machines.
4. Manure Handling
Often seen as the lone detriment to sand as dairy cow bedding, sand-laden manure handling is possible, but you need a plan. There are numerous proven and reliable methods for handling sand-laden manure. One of the best things to do is to avoid handling sand-laden manure using techniques and equipment intended for manure mixed with organic bedding.
The challenges with handling sand-laden manure stem from two factors. First, sand is abrasive, so choose equipment designed to withstand the abrasiveness of sand. This means equipment that operates at low speeds and is constructed using wear-resistant materials like abrasion-resistant steel plate or rubber. Essentially, components in high-wear situations need to either be harder than sand grains or resilient enough to deflect without deforming.
The second challenge is that sand settles, especially after dilution water is added. Sand-laden manure should never be put into tanks where settled sand cannot be safely and reliably removed. Sand-laden manure handling systems usually require additional agitation to fully suspend tank contents and/or ramps to allow for loader access.
Sand-manure separation systems are another option for dairy cow manure management where sand is used for bedding. Separation is accomplished by either sand lanes, which rely on gravity to settle sand and loaders to retrieve the settled sand, or mechanical sand separators, which rely on mining-duty technology to wash manure out of sand. Both systems successfully separate sand from manure. Sand recovery can be high enough to allow for anaerobic digestion (yes, sand bedding can be used along with anaerobic digestion).
5. Sand recycling
Not only are sand separation systems capable of achieving high sand recovery, the separated sand can also be recycled with lactating dairy cows. Recycled bedding sand can potentially offset the cost of purchasing bedding sand by as much as 90-95%.
For sand recycling to occur, separated sand should be as clean and dry as possible. Elimination of organic matter also removes the water-holding capacity of recycled sand. Organic matter content should be as low as possible, with 2% being a maximum.
Recycled sand for dairy cow bedding.
With flush or flush flume systems, sand recovered from sand lanes tends to be wetter than sand from mechanical systems. Nevertheless, acceptable moisture levels can be achieved by stacking (with the drying achieved simply by time) or mechanically dewatered using mining-duty Sand Dewatering Screens.
Dewatering by stacking requires months to achieve an acceptable dryness, whereas mechanical dewatering allows for sand to be immediately recycled. Faster recycling of sand means less sand inventory. Less sand inventory means less cash being tied up in sand.
Sand can also be recycled where scraping or vacuum tanks are used to transport manure. Sand separation and recycling systems function differently than high-dilution sand lane systems since the water used for separating sand is most often acquired using the water obtained using solids separation. Regardless of the method of manure handling and transport — scrape or flush, vacuum tank or flush flume, clean, recycled sand is achievable.
Keep these things in mind when you plan for your next sand barn. Using sand bedding isn’t necessarily difficult, rather it is really just different than using organic bedding. You’ll see the difference in your cows and your bottom line.