Don’t skimp on sand in free-stalls or it could hurt lying time, according to research in the July Journal of Dairy Science.
Researchers at the University of British Columbia measured changes in sand-bedding depth and the impact that this had on lying time.
In one experiment, they found that lying time decreased by 1.15 hours in stalls with sand that was 2.4 inches below the curb compared to stalls filled to curb height. In fact, for every 0.394-inch (1 centimeter) decrease in sand bedding below curb height, cows spent 11 fewer minutes lying down per day.
In another experiment, cows using stalls with the least amount of sand ─ 5.4 inches below the curb ─ spent 2.33 fewer hours lying down per day than when they were given access to stalls filled to curb height. In other words, for every 0.394-inch (1 centimeter) decrease in sand bedding, cows spent 10 minutes less lying down per day.
Previous research from the University of British Columbia shows that poorly-bedded mattresses also decrease lying time.
In the present study, the researchers also made these observations about the depth and displacement of sand in the stalls:
- Over time, the stall surface became concave. In other words, sand depth was lowest at the center of the stall and highest at the edges.
- Loss of bedding was greatest after new sand was added.
- Sand levels continued to decline during the 10-day study period.
- Stalls with higher occupancy times tended to have the greatest loss in sand depth at the end of the study, although it was not statistically significant.
The researchers, all with the University of British Columbia’s Animal Welfare Program, found no difference in the number of lying bouts ─ the duration of time between lying and standing back up again ─ in either experiment. However, cows that spent less time lying down had shorter lying bouts.
The researchers note that this study is the first of its kind to show that sand depth and shape influences lying time. They recommend that sand should be level with the curb. Therefore, groom stalls daily to maintain proper slope and refill them as needed to keep sand at curb level.
July Journal of Dairy Science, pages 2381-2387