2005 Annual Report
Dickinson Research Extension Center
1089 State Avenue
Dickinson, ND 58601
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M.B. Johnson * , V. Anderson ** , D. Landblom *
*Dickinson and ** Carrington Research Extension Centers, North Dakota State University
Research Summary: Preliminary results have not demonstrated a significant improvement in the performance of developing heifers when bedding is added to feedlot pens during winter feeding. In addition, no significant differences were found in nutrient content of fresh manure, although potassium levels tended to be higher in bedded treatments. Further analysis will have to be completed before further conclusions can be made.
This project was designed to assist producers with pen management decisions that aid in the capturing and utilization of nutrients from livestock manure. Previous research has proven that bedding improves cattle comfort and performance, but there is little information on the use of bedding to capture nutrients from livestock manure. Therefore, it was hypothesized that bedding could serve a dual purpose of providing cattle comfort during inclement weather as well as absorb and capture nutrients that would otherwise be lost to runoff or volatilization into the atmosphere. In addition to providing an absorptive material in the pen, bedding also provides the carbon source needed for composting manure. Most research to date has studied the quantity of bedding that should be used whereas this project will focus on the type of bedding.
This project was designed to determine if: 1) bedding type has an effect on animal performance, 2) there is a preferable bedding source for nutrient absorption in the pen, and 3) carbon source effects composting of manure.
One hundred heifers were weighed, blocked by weight, assigned to pens and one of the following treatments: 1) control – no bedding, 2) barley straw, 3) oat straw, 4) corn stover or 5) wheat straw. Each experimental pen contained five heifers and each treatment was replicated four times for a total of 20 pens. Heifers were confined and fed for a total of 111 days. The nutrient composition of the diet can be found in Table 1. During this period heifers were bedded on a weekly basis and weights were taken every 28 days and at the conclusion of the study. Feed was delivered daily and weighed in order to calculate feed efficiency. At the conclusion of the study, heifers were removed from the pens. Pens were scraped and manure and bedding was piled in order to begin the composting process. Samples for nutrient analysis were collected immediately and measurements were taken to estimate pile volume. Piles were monitored weekly for changes in temperature and were turned four times from June to November.
No significant difference was found in the start weight, end weight, average daily gain or feed efficiency of heifers with or without bedding as shown in Table 2. The mild weather and protection from the wind may have lessened the effect of the bedding. There was no significant difference in feed intake among treatments, although, the heifers in the Control treatment tended to eat more during the second feed period (p = .2041). Pen intake for each period can be found in Table 3.
Heifers were bedded each week with approximately 84 pounds of bedding. The goal was to provide approximately 266 pounds of bedding per head over the feeding period based on findings by Birkelo and Lounsbery (1992). Four weeks after initiation of the project it was determined that additional bedding needed to be delivered to create an adequate bedding pack. Sufficient bedding was added to each pen to create a pack and future bedding weights were adjusted to create similar weights among treatments. Heifers received approximately 320 pounds of bedding per head over the feeding period. However, heifers receiving wheat straw had a significantly higher bedding weight than heifers in other treatments. Total bedding weights and volumes can be found in Table 4. Volumes were calculated from three measurements taken immediately after piling. There was a significant difference in volume between the control and bedded treatments. This can be attributed to the additional material that was added to the bedded pens.
Manure samples were sent to NDSU Soils Lab and analyzed for dry matter, (DM), ammonia-nitrogen (NH4), nitrogen (N), phosphorus (P), potassium (K) and organic matter (OM). Results can be found in Table 5. Dry matter was significantly different among treatments. Pens without bedding (control) had significantly higher dry matter. This can most likely be explained by the lack of absorptive material resulting in an increase in runoff. Ammonia-nitrogen values for barley and wheat treatments tended to be higher than other treatments indicating a more stable carbon to nitrogen ratio and reduced nitrogen volatilization. The significantly higher amount of bedding in the wheat treatment may also have contributed to less nitrogen volatilization. No significant differences were found in percent nitrogen, phosphorus, potassium or organic matter amongst the treatment. Lack of differences in manure nutrients could be attributed to varying nutrients in bedding sources. Further analysis of bedding sources will help determine their contribution to the nutrients found in the manure. A difference in organic matter was expected between the control and bedded treatments but was not detected. Feed intake was not significantly different among treatments suggesting that if bedding was consumed by heifers it was not enough to reduce feed intake. Failure to obtain a representative sampling may also have contributed to the results.
Once initial sampling and measuring of manure piles was completed, piles were moved to a location where they could be monitored and turned until the composting process was completed. Two temperatures were taken from each pile on a weekly basis. When pile temperatures, on average, fell below 120 degrees F, piles were turned. Significant differences between treatments were found at several readings. Temperature differences became significant approximately four weeks after piling and remained significantly different for three weeks. Temperatures were similar until the last two weeks of sampling when they became significantly different. Table 6 shows the changes in average temperature to date. Graph 1 shows the temperature fluctuations among treatments.
The nature of this project and the lack of supporting research make it difficult to make conclusions after one year of data collection. Research being conducted this fall at the Carrington Research Extension Center will compliment the data that has been collected thus far, but will represent a different portion of the state.
Birkelo, C.P. and J. Lounsbery. 1992. Effect of straw and newspaper bedding on cold season feedlot performance in two housing systems. South Dakota Beef Report pp. 42-45.
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