Improper grooving of concrete floors is often the biggest mistake made during barn construction, says Curt Gooch, extension agricultural engineer with Cornell University's PRO-DAIRY program. However, it is a mistake that can be avoided.
When a concrete floor is grooved correctly, says Gooch, it will have four desirable traits. A flat, smooth surface between each groove, combined with grooves that are properly spaced with the precise width and depth specified, is what makes for good cow traction. Failure to meet any of these four traits will result in problems for your cows. Here's why you need each trait to get a good groove for your cows.
Make it flat
The first trait of a good grooving job is that the floor space between each groove is flat, or level.
A level surface provides uniform support for a cow's entire foot — not just parts of it. When a cow walks on an uneven surface, and only part of the hoof comes into contact with the surface, it increases the pressure, and the wear and tear, on that part of her foot.
In addition, when a cow walks on uneven floors, it increases the chance that her foot will rotate or rock back and forth until it finds enough contact area to support her weight. Neither is good for the health of her feet.
Make it smooth
Just as it hurts you to walk on rough concrete with your bare feet, it can hurt your cows feet, too. That's why you want the floor to be smooth.
Don't kid yourself into thinking you need a brushed or rough finish on the concrete to give the cows traction — that is what the grooves do. Just like an uneven floor, rough floors put additional pressure on a cow's foot. In addition, a rough finish can increase hoof injury.
So, strive for a smooth finish between the grooves. A smooth surface will provide the proper hoof support your cows need and decrease the potential for hoof damage.
Make groove edges right angles
The edges of each groove should be crisp, not rounded. And that crisp edge should form a right angle with the floor.
A crisp or straight edge does not translate into an edge that is sharp and damaging to the hoof. However, if you end up with fins — displaced concrete that hardens after the grooving process — sticking up along the edge, then that's a problem. But a solid right angle on a groove is the way to go.
Failure to accomplish this trait results in edges that cause a cow's weight to be unevenly distributed. It also results in sharp edges that can cut the sole of the hoof.
Make precise measures
Proper groove measurements have developed over time. Make the spacing between grooves too wide or too narrow, and they won't provide the traction your cows need. European research suggests the distance between grooves should be about 2 inches.
When a cow puts her foot down on a floor with grooves spaced more than 2 inches apart, her foot tends to slip from its initial placement. That means her foot, in essence, slides until she catches the edge of the next groove. Depending on the distance between the groove, her foot could accelerate enough to cause her to slip and fall.
On the other hand, with grooves spaced less than 2 inches apart, the flat surface between the grooves may not provide enough contact area to support the hoof. This again leads to uneven weight distribution and certain points on her hooves take more than their share of wear and tear.
In addition to the space between the grooves, you also must be concerned about the width and depth of each groove. The goal is that each groove should measure 0.5 inches wide and 0.5 inches deep.
Grooves that are too wide will lead to the same uneven floor problems mentioned before. Whereas grooves that are too narrow do not provide enough traction for cows, and they will have the tendency to slide right over them.
Grooves that are too deep tend to cause cracking of the concrete. Cracked concrete can settle, which leads to uneven flooring. And grooves that are too shallow can be quickly worn down by frequent scraping and eventually disappear.
Four desirable traits
To get a good grooved floor that delivers the traction your cows need, you have to demand all four traits be met by your contractor. Three out of four is not good enough.
Lameness is the third- highest-cost health problem on dairies today. And bad flooring, even just as simple as not meeting one of these criteria, can quickly move it to the top of the list for the most expensive health problem on your dairy.
Five aspects to include in a contract
Many mistakes made during the grooving process can be avoided by working closely with your contractor. Curt Gooch, extension agricultural engineer with Cornell University's PRO-DAIRY program, suggests that you include the following items in a signed contract before your contractor pours the concrete:
Specifications for what the finished product should look like, particularly groove spacing, width, depth and the area between the grooves. In general, grooves should measure 0.5 inches wide and 0.5 inches deep, and be spaced 2 inches apart. The area between the grooves should be flat, smooth and square.
Be sure to state that errors in the finished product will be fixed at the contractor's expense.
The quality of the concrete to be used relative to its compressive strength. Specify the concrete's strength — 3,500 psi (pounds per square inch), for example. Also specify what admixtures are needed, such as air entrainment and water reducers. Air entrainment makes the concrete more resistant to weather conditions, and water reducers make the concrete easier to work with — without sacrificing ultimate quality.
A maximum "slump." Slump refers to the technique a contractor uses to measure the amount of water in the concrete. The higher the slump, the more water it contains, and consequently, the weaker it is. Specify that the slump should not exceed 4 inches for concrete without a water reducer added.
A clause that states the contractor will cure freshly poured concrete for a period of three to five days after pouring. Several methods can be used to do this, including covering the area with 6-millimeter plastic film or using a sprayed-on vapor barrier.
Four common grooved-floor problems
The following photographic guide shows four common mistakes that can occur with grooved floors: