By developing an overall manure management strategy the company has overcome what was a major problem and has significantly reduced the cost of handling manure.

The overall strategy includes pen and catchment design, stockpile design and management, water management, manure processing and product marketing.

1. Pen and Catchment Design

Good pen design is an integral part of successfully managing manure and maintaining the well being of the animals. Wainui determined that the optimal design for feedlot pens has a 3-degree slope along the length of the pen and a 0.5-degree slope along the width. The 3-degree slope allows effective water runoff and avoids wet spots. The slope also encourages a general movement of manure towards the bottom of the pens into catchment channels through the movement of water and cattle. The 0.5-degree slope allows movement of water but minimizes movement of material across the pens. Removing the material from the pens helps prevent polluted water seeping into subsoils and underground aquifers.

2. Stockpile Management

As manure accumulates in the pens, the surface is scraped and pushed up into mounds in the center of the pen. This preliminary stockpiling allows for some decomposition and dehydration, which reduces the volume to weight ratio by up to 34 percent. This greatly reduces the amount of manure that needs to be handled and therefore, reduces the associated costs.

Material is periodically removed from the pens as the stockpile volume increases. New material is spread over the existing pile evenly to allow for effective compaction and decomposition while eliminating the risk of spontaneous combustion. Also, the stockpile hardens quickly and resists water making is easier to work with machinery.

3. Water Management

As well as pen design that optimizes flow and catchment of water throughout the feedlot, Wainui has undertaken a number of activities to conserve water use on the property.

Cattle water troughs are emptied and replenished with fresh water approximately 2-3 times per week. The feedlot now reuses this water for dust suppression on the roadways rather than relying on fresh bore water. Dust suppression is important in cattle feedlots because of the effect it has on the well being of the cattle. Excessive dust is detrimental to animal health and performance and may irritate eyes and increase susceptibility to disease and respiratory disorders and create general stress.

Watering of the roads also reduces the need for road maintenance. The cost of maintaining the 5 kilometers of roads is currently $15,000 per annum. Regular watering is estimated to save $10,000 per annum in road maintenance. This practice has also reduced the cost of tires for the six trucks used on the property by $3,600, around 30 per cent of the total cost.

The roadways require watering every day, which uses around 210,000 L of water each week. By reusing the water from the animal troughs, a saving of 90,000L of water is made every week. This translates to water saving of approximately 4.7 ML per annum and a cost saving of $500 to $1,000.

Water that is used for cleaning the livestock facility after livestock induction to the feedlot is also reused. Approximately 5,000 liters is used during this process, most of which is collected as runoff. This water is then used to irrigate crops and grassland on the property, which once again reduces the drain on the fresh water supply.

4. Manure Processing and Marketing

The handling of manure typically costs around $7.50 to $9.00 per ton, which includes scraping the pens, mounding in the pens, periodical removal of manure from the pens, stockpiling, screening and general handling of the manure. Annually this costs $75,000 to $90,000.

In order to reclaim some of these costs, Wainui produces a saleable product - Moo Poo. This product is sold to farmers in the area and producers of commercial soils for approximately $6.50 per ton, excluding transport. This generates around $65,000 per annum in revenue. While this is currently less than the production cost, the practice is essential as it removes 10,000 tons of material from the property that could otherwise become a serious problem.

The value of the product to farmers is significantly greater than its current price. The estimated value of an organic matter, the NPK nutrients and other trace elements is between $35-50/ton.

The company inherited a manure stockpile from the previous owners, which is contaminated with rocks that were used to line the bottom of the pens. This stockpile is outside the water catchment area so must be decommissioned to meet council requirements.

When Wainui built the new stockpile it started to keep accurate records of the volume of material. As the old stockpile is eliminated the company will be able to develop a more stable market for their manure product that equals their annual production. This should lead to higher (or at least more stable) prices in the future.

Environmental and Economic Benefits:

The major benefits of the manure management program are summarized in the following table:

	The time and cost associated with handling the manure was significant. Strategies to reduce the overall volume of material would have a significant impact on the cost of the operation.
	The stockpile design created significant management problems. Mounds were not well compacted, so could often not be worked with machinery (particularly in wet weather). The loose compaction created a buildup of flammable gases that sometimes resulted in spontaneous combustion of the stockpile. These fires required approximately 100 hours of labor and the use of a loader to control each year.