1a. Objectives (from AD-416):
To compare bedding systems utilizing recycled byproducts of manure separation (recycled sand, organic solids) against the industry standard (new sand) for lactating cows housed in freestalls.
1b. Approach (from AD-416):
The current industry standard for freestall bedding is new sand. Previous research has documented reduced frequencies of lameness in cows bedded with sand compared to non-sand bedding types. These benefits may be derived from several physical properties of sand, and include: i) the ability to cushion and conform, thereby improving stall use and time lying down by improving cow comfort; ii) improved traction in the stalls, aiding cows attempting to rise or lie down; iii) improved traction in alleyways, where sand kicked out of the stalls by cows may prevent slippage on smooth concrete; and iv) reduced frequencies of hock abrasions. Unfortunately, these potential benefits are offset (somewhat) by concurrent complicating effects on manure-handling operations; producers seeking to separate organic solids from manure must first separate sand. Furthermore, the generally abrasive nature of sand in manure systems increases wear on pumps and other mechanical equipment. As a result, some producers are beginning to question if the advantages in cow comfort attained with sand bedding outweigh the costs and frustrations of maintaining mechanically operated manure-handling systems. The University of Wisconsin and the USDA-ARS have entered into a cooperative partnership at the University of Wisconsin Marshfield Agricultural Research Station (MARS). Through this venture, a 128-cow lactating barn is nearing completion, and will soon be populated with lactating cows. At MARS, the manure-handling system produces several byproducts that potentially could be used as bedding materials, including separated organic solids and recycled sand. However, questions often are posed by producers about the suitability of these byproducts for this specific purpose. Clear demonstration of statistically similar performance between these byproducts and new sand would offer great potential cost savings to producers. Proposed bedding systems include new sand, recycled sand, deep-bedded organic solids, and shallow-bedded organic solids sprinkled on top of mattresses with a foam core. The mattress system does not require permanent attachment; therefore, mattresses can be rotated throughout the four identical quadrants in the barn during four experimental periods lasting one calendar year each. The experimental design will be a 4 x 4 Latin Square. Response variables include: stall and cow cleanliness scores, assessments of cow comfort, incidence of lameness, nutrient composition of manure scraped from each quadrant of the barn, indices of milk production and animal performance, incidence of mastitis, and assessment of bedding type on pathogen survival.
3. Progress Report:
This project relates to Objective 1 in the parent project: Determine the effects of dairy cattle diet and dairy herd management (e.g. pasture, confinement, hybrid systems) on manure nutrient excretion, capture, recycling, and loss via gaseous emissions, leaching, and runoff. Recycled bedding materials have been stockpiled, and continued work is ongoing with respect to handling, storage, and monitoring of these materials for use in the lactating cow barn at the Marshfield Agricultural Research Station. One bedding treatment within the barn requires a thin layer of recycled organic solids to be placed on top of foam-core cow mattresses. These comfort mattresses have been purchased and installed in one quadrant of the barn. Installation of ventilation fans within the freestall barn was completed during 2012. Most recently, a protocol has been developed to dry organic solids to an acceptable concentration of water before they are transferred to the freestall barn. This pre-conditioning of organic solids was the last remaining preliminary step in the project, and data collection is scheduled to begin during June 2013.