Are Your Cows Getting Enough Rest?
Posted: December 9, 2008
At the recent Penn State Dairy Cattle Nutrition Workshop, Dr. Nigel Cook from the School of Veterinary Medicine at the University of Wisconsin presented results of on-going research into the daily time budgets of cows. Their studies use video surveillance to determine how cows spend their time and how management practices and facility designs influence cow behavior.
Results of the Wisconsin research suggest that cows housed in free stalls need about 12 hours of rest each day. Cook outlined five challenges that can prevent cows from getting this rest: prolonged time spent milking, competition for stalls (overstocking), poor stall design, inadequate heat abatement, and excessive time in lock-ups.
Cows have about 2.8 hours per day available for milking, that’s 56 minutes per milking for 3X or 84 minutes per milking for 2X, and this figure includes travel to and from the parlor, time in the holding pen, and actual milking time in the parlor. Cook suggested that this time must be considered in addition to turns per hour when determining group sizes based on parlor throughput. When milking time exceeds this limit cows have no choice but to reduce resting time. In addition, time out of the pen that is due to long distance travel to the parlor can compound the problem by wearing down the hoof sole, increasing lameness, and resulting in cows that walk more slowly, further increasing time out of the pen.
Overstocking is an effort to squeeze as much efficiency as possible out of the facility, and cows can tolerate it to some extent. Research suggests that negative effects are minimal at 1.2 cows per stall, particularly for pregnant and late lactation cows. But, Cook cautioned that transition cows must have one useable stall per cow. In addition a recent study of 108 herds showed that overstocking cows in breeding or high group pens reduced overall herd average conception rates.
Stall design is a major factor contributing to the amount of time cows spend lying in stalls. Stalls must not restrict the cows’ ability to lie down or rise and must provide adequate resting space for the size of cows in your herd. Cushioning of the stall surface is the final consideration. Cook’s research shows that the main determinant of whether cows lie or stand in stalls is lameness, and if the stall surface is not cushioned, lame cows will stand in stalls rather than lie down. “Thus,” Cook explained, “poor stall design leads to lower lying times and increased risk for lameness, and once cows become lame they behave differently than non-lame cows in the same stall design, leading to even lower lying times!” Deep sand bedding offers the best combination of cushioning and traction and remains the gold standard for free stall bedding. Cook reported that he has observed milk production increases of 1,000 to 4,000 pounds per cow per lactation when mattress stalls have been converted to sand (average of 2,000 pounds per cow over 1 to 2 years).
When core body temperature rises above 102 degrees F, mature Holsteins seek shade and stand rather than lie down. In addition, cows that spend more time standing in the alleys under soakers or fans spend less time lying. A survey of 29 free stall barns in the Upper Mid-West and California found the following factors were most important in cooling cows and improving conception rates in summer: orienting naturally ventilated barns from East to West, lowering stocking density in breeding pens, providing 1,000 cubic feet per minute per cow of ventilation in the holding pen, reducing time in the holding pen and parlor, providing fans over the resting area, and using soakers in the holding area.
The final challenge Cook discussed was excessive time spent in lock-ups. Cows seem to be capable of compensating for a 1 to 2-hour change in their routine. But, if cows are held away from stalls for longer periods or if other stresses, such as overstocking, are present, lying time may be reduced. Cook noted that the cows most at risk – fresh cows – are probably the ones we lock up the longest. Research suggests that cows should be locked up no more than 2 hours per day, and at least 1 hour of that time fresh feed should be available to them. Exceeding these limits will likely result in decreased resting times.
For more information about time budgets and their effect on cow performance, see Dr. Cook’s paper in the conference proceedings at das.psu.edu/dairy/dairy-nutrition.Summarized by Coleen Jones, Research Associate, Department of Dairy and Animal Science