Validation of Feed and
Manure Data Collected on Wisconsin Dairy Farms
J. M. Powell,*1 D. B. Jackson-Smith,†
D. F. McCrory,2‡ H. Saam,‡3 and M. Mariola§
Abstract
An on-farm study of 54 representative
Wisconsin
dairy farms was conducted to evaluate the influence
of
biophysical and socioeconomic factors on overall feed,
fertilizer, and manure nutrient use. This report validates
1) how well data on cow diets, feed analyses, and
milk production reflected established feed-milk-manure
relationships; and 2) how well farmer-recorded
data on manure land application reflected literature
values of manure N and P excretion, collection, and
loss. Calculated feed N and P use efficiencies (18
to 33%
and 18 to 35%, respectively) fell within ranges expected
for dairy farms. This suggested that our on-farm methods
of data collection provided reliable information on
relationships among feed N and P intake, secretions
in
milk, and excretion in manure. On stanchion farms,
there were no differences between farmer estimates
(kg/
farm) of manure P collected (1,140) and land-applied
(1,210) and what would be calculated from the literature
(1,340). On freestall farms, there were no differences
in amounts (kg/farm) of manure P collected
(2,889), land-applied (2,350), or literature estimates
(2,675). Manure P applications (kg/ha) to tilled cropland
would be similar using either farmer estimates of
manure
collected and land-applied, or literature estimates.
The data provided a snapshot of Wisconsin industry
practices, as well as information on the range of
feed
and manure management practices on individual dairy
farms. Improvements to data collection methods would
require increased skill and training of both farmers
and
those responsible for assisting farmers in on-farm
data
collection and analyses.
Keywords: feed,
manure, nutrient use efficiency, onfarm data,
Organig farming.
