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Journal of Environmental Quality Abstract -

Protein Content in Dairy Cattle Diets Affects Ammonia Losses and Fertilizer Nitrogen Value


This article in JEQ

  1. Vol. 27 No. 3, p. 528-534
    Received: May 28, 1997

    * Corresponding author(s): paulj@em.agr.ca
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  1. J. W. Paul *,
  2. N. E. Dinn,
  3. T. Kannangara and
  4. L. J. Fisher
  1. Agriculture and Agri-Food Canada, Pacific Agriculture Research Centre, P.O. Box 1000, Agassiz, British Columbia, Canada V0M 1A0;
    Department of Animal Science, Univ. of British Columbia, Vancouver, B.C. Canada V6T 1Z4.



Altering feeding strategies for dairy cattle (Bos taurus) may reduce manure N excretion and NH3 emission from the manure. We determined the effect of dietary formulation on NH3 emission immediately following manure excretion and the availability of manure N for plant growth. Manure (urine and feces) was collected from dairy cattle fed diets containing crude protein levels of 16.4% (T1High), 15.3% (T1Med), and 12.3% (T1Low) in trial 1, and 18.3% (T2High), 16.7% (T2Med), and 15.3% (T2Low) in trial 2. Ammonia emission was measured in the laboratory for up to 48 h. Emissions during the first 24 h following manure excretion were 38 and 23% of the total manure N from Diets T1High and T1Low, and 22, and 15% of the total manure N from Diets T2High and T2Low. Manure NH+4 concentration and pH were positively related to the dietary crude protein level. Manure from cattle-fed diets T1Med and T1Low were applied to soil at two rates to determine short-term N availability for three plantings of corn (Zea mays L.) grown for 30 d each in the greenhouse. The recovery of manure and fertilizer N in the plants and the soil for the first two plantings was 48, 31, and 103% for the T1Med, T1Low, and inorganic N treatments, respectively. Whole farm N utilization for diets T2High and T2Low were estimated at 18 and 23%, respectively. Feeding diets lower in crude protein increases efficiency of N on the dairy farm, decreases NH3 emissions following excretion but also decreases the short-term N availability of the manure.

Contribution 564.

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