Running a successful dairy involves navigating a range of variables, such as breed, feed mix, barn layout, bedding type and more. There is one topic, however, every farmer will have to face, which has an impact on the function of the entire barn: manure.
A successful manure management strategy takes into account animal health and safety, impact on yields, recycling potential and, in the case of this article, selection of bedding material. While sand bedding has long been considered the gold standard for cow comfort and animal welfare, it creates unique and potentially costly challenges for manure management.
The importance of good manure management
A well-planned manure strategy is key to the success of any dairy. Considering an average U.S. dairy (approximately 300 head, 100 pounds of manure per cow per day) produces roughly 11 million pounds (approximately 5,500 tons) of manure every year, farmers are forced to contend with how to manage such a volume of waste. Moreover, poor manure management can lead to costly hoof conditions and lameness as the result of slippery floors and hooves consistently covered in manure.
In fact, according to a study conducted by the University of Wisconsin – Madison Division of Extension Dairy, “a case of lameness can cost $90 – $300. Even with using $90 per case, the cost to a 300-cow dairy with a 20% incidence rate would be over $5,400.” The study also illustrates how lameness impacts a cow’s ability to move to feed, rest comfortably and reproduce, ultimately reducing yields. The study states, “Another way to look at this is if a 300-cow herd had a 15% incidence rate [of sole ulcers], that could amount to $8,910 per year in milk loss.”
Some farms benefit financially from their manure management, recycling manure into fertilizer, running nitrogen separators or methane digesters, or even using screw press drying systems to turn manure into new bedding. All of these methods have the potential to offset costs while upcycling what, in many cases, is considered a waste product.
Methods of manure management
Processes for managing manure have evolved considerably over the years. The manual process of shoveling was gradually replaced with scraper systems, either mounted on the front of a skid steer or tractor, or pulled by a motor-driven chain or cable. While these systems carry a low upfront cost, they provide obstacles to cows and machinery movement, and have the potential to leave alleys slick with a thin layer of manure, potentially leading to slipping and hoof conditions. Scrapers can also experience much higher wear and replacement costs in sand-bedded barns.
Flush systems have seen a degree of popularity but need to be run frequently and require enormous amounts of water. While there are advantages to flush systems in terms of separating solids to be used as fertilizer and the ability to reuse some of the water in the next flush, construction considerations and capital costs often act as barriers for dairy producers. They also end up washing any loose sand into the collection lagoon, adding to filtration and separation requirements.
In the past 20 years, automated manure management systems have emerged as an innovative solution, opening up new possibilities for managing manure in dairy barns, especially those using sand bedding. Robots have the potential to reduce labor costs, improve barn hygiene and help prevent the mechanical wear issues associated with sand bedding.
Why sand?
Among the primary reasons dairy farmers choose sand bedding is the comfort it offers cows, providing a stable, supportive surface that allows them to lie down comfortably, reducing stress and pressure on their joints. Additionally, sand’s natural inorganic properties contribute to better hygiene. It drains well, which prevents excess moisture from accumulating in stalls, reducing the risk of common infections. The reduced moisture also makes it harder for bacteria to thrive, lowering overall bacterial load in the barn. Sand also provides superior traction, meaning cows have sure footing when moving throughout the barn. With all these benefits, it’s not difficult to see why sand is the most popular choice.
While providing a best case scenario for cows, sand can quickly become a headache for manure management equipment. Sand is abrasive, leading to increased wear on manure handling systems such as pumps, scrapers and separators, resulting in more frequent maintenance and higher overall replacement costs.
In traditional systems, these drawbacks are weighed against the benefits and mitigated through separation, use of stronger (and subsequently more expensive) equipment or a more aggressive cleaning and maintenance schedule.
Dirty robots, clean floors
Over the past two decades, robotic systems have started to increase in popularity as an approach to manure management. They save money on labor, eliminate fuel costs from running a skid steer or tractor-based scraper and are far less invasive to a cow’s natural rhythm in the barn as they are smaller than a traditional scraping system and nearly silent. Rather than running at pre-set times, robots can clean a barn 24-7, typically resulting in more consistently clean and safe floors.
Much like their traditional counterparts, robotic solutions to manure management employ various methods of actually removing the manure from the floor. Some manure robots use mechanical scraping systems mounted at the front of the robot. While these systems provide the benefits of reduced labor and around-the-clock cleaning, they still suffer from many of the same sand-based downfalls, including increased wear and replacement costs.
Other robotic systems use a water and vacuum system to clean manure from the floor. While this adds a water requirement to the cleaning process, the overall consumption is lower, and the spray-and-vacuum method has the potential to leave floors safer and more sanitary than scraping. This method of manure removal also reduces the wear on mechanical components, potentially leading to reduced lifetime cost of operation and less frequent maintenance. Until recently, spray and vacuum robots were not ideal for sand-bedded barns as they would provide a clogging hazard. However, recent advancements have enabled them to be outfitted with sand flush systems, separating out the abrasive material from the manure and making them more suited for sand-bedded barns.
Final thoughts
While sand bedding may provide unique challenges for developing a successful manure management strategy, continued innovation in dairy technology has made it possible to utilize sand in strategies that were previously unavailable.
References omitted but are available upon request by sending an email to the editor.
