Extension Ag Update
May/June 2003
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Manure Evaluation Field Study

Mike Hutjens, Extension Dairy Specialist, University of Illinois, Urbana

In the September 19th issue of Agri-View, an interesting article on manure evaluation was reported from a presentation by Mary Beth Hall, University of Florida. “Reading” manure continues to be an active area of interest on dairy farms. Dairy managers, feed consultants, veterinarians, and feed company specialists see manure changes and attempt to interpret these changes. Personnel from Dairyland Labs report manure samples are sent in for evaluation, but guidelines are needed to interpret and apply in the field. Discussions with Vita Plus Corporation have raised similar questions. Can manure samples be analyzed in a lab and “tells” us anything about the herd or cows?

To answer this question, Becky Meier, a senior in animal sciences from Ridott, Illinois, conducted an honors project collecting information on manure variation. The study had the following format.

  1. Collection of manure sample of from research cows on a current University of Illinois study. One cow was sampled three times during the collection period (#6921) to see if changes occurred in early lactation.
  2. Cows in the manure study had been on a transition cow study by Heather Dann. Manure sample were collected within 60 days after calving (all cows were on the same diet after calving). Information on dry matter intake, days in milk, and milk yield was collected on day of sampling.
  3. Five hundred grams of fresh manure were washed through screen number 8 (2200 micron), number 16 (1120 micron), and number 30 screens (500 micron); dried at 55 degrees until a stable weight was achieved, and weighed to measure amount of particles on each screen.
  4. Second set of fresh manure sample was collected and sent to Dairyland Labs for dry matter, pH, and starch content.

A complete summary will appear in the 2003 Illinois Dairy Report. The following points can be observed.

  1. A wide range in fecal starch was observed varying from 2.3 to 22.4 percent.
  2. Fecal pH varied from 5.4 to 6.5 units.
  3. Fecal dry matter ranged from 9.2 to 11.6 percent.
  4. A wide range in milk yield (75 to 119 pounds), dry matter intake (44.3 to 60.7 pounds), and days in milk were in the data set.
  5. The one fresh cow monitored did not vary greatly during three weeks in early lactation.

We will be statistically analyzing the data to see if relationships exist.

Field Applications of Manure Evaluation

Two ways to evaluate manure on farms can be used even if manure analysis is not conclusive and needs more study.

Method 1. Monitor manure scores (1 as very watery to 3 as ideal to 5 as stiff and stacking) as rations change and cows increase in days in milk.

  1. Fresh cows could range from 2 to 2.5
  2. Early lactation cows can range from 2.5 to 3.0
  3. Mid to late lactation cows may range from 3.0 to 3.5
  4. Dry cows can range from 3.5 to 4.0

Manure scores below 3 may be due to lack of rumen transition when shifting cows from the dry to early lactation ration, too much protein is fed, excessive starch intake occurs, high mineral intake is happening, and/or a lack of functional fiber exists.

Method 2. Wash a cup of manure (about 8 ounces of wet manure) using a number 8 screen (eight squares to the inch or 1/8 inch openings) to monitor the following.

  1. If more than 8 to 10 intact cottonseeds (fuzzy removed) remain, nutrients inside the seeds are lost (due poor rumination or lack of functional fiber).
  2. If whole or split roasted soybeans exist, additional processing is needed.
  3. If partial or whole corn kernels remain from corn silage, the corn silage was not processed, was processed incorrectly, and/or was too mature at harvest.
  4. If small pieces of corn grain remain on the screen from corn grain, the grain was not processed adequately.
  5. If forage particles over 0.5 inch remain on the screen, forage digestibility and quality can be a limitation.

Manure evaluation can be a useful field tool and diagnostic benchmark. Unfortunately, manure analysis has limited application at this point.

Protecting and Supplementing Large Round Hay Bales With Salt-Starch Coverings

Nathan A. Pyatt and Larry L. Berger, Dept. of Animal Science, University of Illinois

This study was conducted two years in a row. Twelve twine-wrapped large round alfalfa-grass mix hay bales from first cutting hay were used to evaluate six alternatives for storing bales. Treatments included placing bales on wooden forms and then covering bales with plastic, or a salt-starch matrix (SSM), or SSM with 5% sodium bentonite, or SSM with 5% sucrose. Bales were also left uncovered and others were placed directly on the ground uncovered. The treated bales remained in storage for more than 200 days and then fed to angus cows. Bales were analyzed for storage losses, change in quality and feeding acceptance. Results indicated that the plastic cover provided the most protection against the weather. The amount of rainfall greatly influenced the effectivement of the SSM. The plastic covered bales also had less storage losses. There was no significant change between treatments in the crude protein. Using wood forms to create a moisture barrier did reduce bale spoilage. The tarp bales had the greatest number of days fed per bale. The salt-starch covered bales averaged a 1.09 unit increase in relative feed value during storage. The cows did increase the percent feed refusal when fed to cows intact. The palatability may not be a problem in chopped hay. For the detailed report, look at the webpage.