Click on “Download PDF” for the PDF version or on the title for the HTML version.
If you are not an ASABE member or if your employer has not arranged for access to the full-text, Click here for options.
IMPACT OF CLEANING FREQUENCY OF PENS AND CARBON TO NITROGEN (C:N) RATIO AS INFLUENCED BY THE DIET OR PEN MANAGEMENT ON N LOSSES FROM OUTDOOR BEEF FEEDLOTS
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org
Citation: Pp. 397-404 in the Ninth International Animal, Agricultural and Food Processing Wastes Proceedings of the 12-15 October 2003 Symposium (Research Triangle Park, North Carolina USA), Publication Date 12 October 2003. 701P1203.(doi:10.13031/2013.15275)
Authors: G. E. Erickson J. R. Adams, T. B. Farran, C. B. Wilson, C. N. Macken, and T. J. Klopfenstein
Keywords: Nitrogen emissions, Beef feedlots, Nutrient management, Manure management
Nitrogen losses from outdoor feedlots are an important environmental issue facing beef producers.
Two methods that may lower N losses are cleaning pens more frequently to prevent exposure of
manure N during collection on pen surfaces or increasing the C:N ratio of manure by increasing
organic matter (OM) on the pen surface. Feeding diets lower in OM digestibility or directly adding
OM to pen surfaces may increase the C:N ratio and decrease N losses.
(Download PDF) (Export to EndNotes)
In Exp. 1, calves in the winter/spring or yearlings in the summer were fed diets lower in
digestibility (BRAN) or fed in pens with sawdust additions (SAWDUST) to increase the C:N ratio
and OM on the pen surface. These two treatments were compared to conventional feeding and pen
management systems (CONTROL). While decreasing digestibility did depress performance as
measured by feed efficiency, feeding BRAN did increase OM on the pen surface and decreased N
losses compared to CONTROL in the winter/spring but did not affect N losses or increase manure
N during the summer. Adding SAWDUST directly to pens yielded similar results to BRAN, with
decreased losses in the winter/spring and little effect during the summer compared to CONTROL.
However, when manure was composted, N recovery during composting was increased for both the
BRAN and SAWDUST treatments compared to CONTROL suggesting that OM may decrease N
losses when manure is composted.
In Exp. 2, diets similar to CONTROL and BRAN were evaluated as a 2 X 2 factorial treatment
design experiment. The other factor evaluated was cleaning frequency. Pens were either cleaned
monthly or cleaned once at the end of the winter/spring feeding period. Performance of steers was
similar to results in Exp. 1, with lower feed efficiency for cattle fed BRAN compared to the
CONTROL treatment. Dietary treatment and cleaning frequency treatments interacted for N
balance in the feedlot. Nitrogen losses were decreased and manure N increased for cattle fed BRAN compared to CONTROL if pens were clean monthly. If pens were not cleaned until the end
of the feeding period, diet had little effect on N losses. Interestingly, N losses were similar
between both cleaning frequency treatments for cattle fed CONTROL.
In Exp. 3, 54 pens were used to evaluate the impact of monthly cleaning on N removal in manure
during the summer months. The same diet was fed in all pens, resulting in similar performance
across treatments. Cleaning pens monthly increased the amount of manure N removed per steer by
3.74 kg or 66.2% compared to pens cleaned once at the end of the feeding period.
These data suggest that cleaning pens more frequently and adding OM to pen surfaces or compost
may decrease N losses from outdoor feedlot pens. Treatment responses appear to be dependent on
ambient temperature or season, suggesting that future research needs to address both summer and
winter/spring feeding periods typical of beef cattle operations.