Growing Beef Newsletter
June 2025, Volume 15, Issue 12
Manure Matters: Comparing Compost, Bedding Pack, and Fresh Manure for Livestock Producers
Beth Reynolds, IBC program specialist, and Carolyn Ihde, small ruminant outeach specialist
All livestock producers know that manure is more than just a byproduct. It’s a valuable resource that, when managed properly, can enhance soil health, reduce input costs, and support sustainable farming. Right now, producers are looking to clean up feeding areas after first cutting hay is up, and livestock are actively grazing, making it a good time to review the difference between fresh manure and compost and some best management practices for both. How you handle and apply manure—whether fresh, composted, or as part of a bedding pack—can make a big difference in outcomes for your land, livestock, and the environment.
Understanding the Difference
Fresh manure is typically collected and applied directly to fields. It contains high levels of readily available nitrogen, often ranging from 10 to 20 pounds of total nitrogen (N) per ton, 4 to 10 pounds of phosphorus (P₂O₅), and 8 to 20 pounds of potassium (K₂O), depending on the livestock species and diet (USDA NRCS, 2020).
Composted manure undergoes a controlled aerobic decomposition process. During composting, nitrogen content typically decreases due to volatilization, resulting in lower total N (around 5 to 15 pounds per ton), but with more stable organic forms. Phosphorus and potassium levels remain relatively stable, often in the range of 4 to 8 pounds of P₂O₅ and 6 to 15 pounds of K₂O per ton (USDA NRCS, 2020).
Composting can reduce manure volume and nitrogen content while increasing the uniformity and stability of nutrients in manure. Turning and handling the manure to support the composting process will increase costs, meaning producers must weigh the cost of composting and loss of nitrogen against the benefits of reduced manure volume for land application.
Bedding pack systems allow manure and bedding to accumulate over time. Nutrient content in bedding packs varies widely depending on bedding material, animal density, and age of the pack. Typically, bedding pack manure contains 5 to 12 pounds of total N, 3 to 6 pounds of P₂O₅, and 5 to 12 pounds of K₂O per ton (USDA NRCS, 2020).
A significant amount of manure applied to fields will be between fresh manure and compost. Testing manure stockpiles is strongly recommended in order to best manage the nutrients applied. The ISU extension publication “How to Sample Manure for Nutrient Analysis” can guide producers through the process of sampling manure.
Evaluating the Pros and Cons
Fresh manure provides a quick nutrient boost, especially in nitrogen, which is beneficial for fast-growing crops. However, its high moisture content and raw state make it prone to nutrient leaching and volatilization. It also emits strong odors and can harbor pathogens, making it less suitable for use near water sources or populated areas. Additionally, fresh manure can attract flies and pests, creating nuisance and health concerns.
Composted manure, while lower in immediately available nitrogen, offers a more balanced and environmentally friendly option. The composting process stabilizes nutrients, reduces odors and pathogens, and produces a product that is easier to spread evenly. The slow-release nature of composted nutrients supports long-term soil fertility and reduces the risk of nutrient spikes. Compared to fresh or bed pack manure, composted manure significantly reduces fly and odor issues by stabilizing organic matter and eliminating fly larvae habitats through heat and microbial activity.
Bedding pack manure is a practical solution for winter housing systems. It reduces labor during cold months and provides a warm, dry environment for livestock. When managed properly, bedding packs can begin composting in place, reducing volume and stabilizing nutrients. However, nutrient distribution can be uneven, and additional composting may be needed before field application.
Application on Pasture and Hay Fields
Applying manure or compost to perennial forage acres requires careful consideration. Thick layers of manure can smother forage, reducing regrowth and productivity. Nutrient runoff is another concern, particularly on sloped or saturated ground, and applications should be avoided during wet seasons or when animals are actively grazing.
Applying manure to perennial forage acres can pose a health risk. Fresh manure can harbor a variety of pathogens, including Escherichia coli O157:H7, Salmonella spp., Listeria monocytogenes, Clostridium perfringens, and Campylobacter spp. These pathogens can survive in manure for extended periods—ranging from several weeks to several months—depending on environmental conditions such as temperature, moisture, and sunlight exposure (Ingram et al., 2005).
- E. coli O157:H7 can survive in manure for up to 70 days under cool, moist conditions.
- Listeria monocytogenes can persist in manure-amended soils for over 100 days.
- Salmonella has been documented to survive in dry manure for up to 6 months.
For example, a potential risk when applying manure is Johne’s disease, a chronic and often fatal intestinal infection caused by Mycobacterium avium subspecies paratuberculosis (MAP). This bacterium is shed in the feces of infected animals and can survive in manure and soil for extended periods. Young animals are especially susceptible to infection, typically acquiring it by ingesting small amounts of contaminated manure from the environment, including hay or pasture that has been fertilized with fresh manure (APHIS, 2024).
To reduce these risks:
- Avoid applying fresh manure to hay fields within 90 days of harvest.
- Compost manure to kill pathogens and parasite eggs through sustained high temperatures (131°F or higher for at least 3 consecutive days.)
- Incorporate manure into the soil, when possible, to reduce surface contamination.
- Keep young animals away from areas recently fertilized with fresh manure, especially if Johne’s is a concern in the herd.
Choosing the right manure management strategy depends on your operation’s goals, resources, and environmental conditions. For more information, contact your local ISU Extension office or visit the Iowa Manure Management Action Group (IMMAG) website.
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