The Roundup Ready alfalfa (test alfalfa) was genetically
modified alfalfa line J101 × J163 expressing the
CP4 EPSPS protein. The test alfalfa forage field was
planted in spring 2004 in southeastern Washington
State, and glyphosate was applied to control weeds before
first cutting. The test alfalfa was first cut in June
followed by a second cutting in July 2004 at the late
vegetative stage and harvested without the use of preservatives
into large (approximately 680 kg) bales as
hay. Three conventional commercial alfalfa varieties
were similarly planted and harvested in southeastern
Washington. One conventional alfalfa variety (control)
was grown next to the test field, weeds were controlled
using nonglyphosate postemergence herbicides, and the
hay harvested into large bales. Two other conventional
varieties (REF1 and REF2) were grown in the same
region by commercial hay producers, planted and managed
similarly to the control, and harvested, instead,
into small (approximately 36 kg) bales. All hays were
cut and allowed to dry in the field to approximately
15% moisture before baling with only first-year secondcutting
hay used in this study. The 2 reference hay lots
were purchased from commercial hay producers and
intentionally selected for use because they were nutritionally
similar to the test and control hays (i.e., values
for CP and NDF composition were similar). Each bale
of each of the 4 hays was individually labeled and
shipped to the University of Wisconsin Agricultural Experiment
Station at Arlington during the fall of 2004.
All alfalfa hays were stored at ambient temperature in
1 of 2 secured buildings until the feeding trial. Before
feeding, hays were chopped through an AgriVal Agri-
Chopper (DC Atlas Company, Loyal, WI) without the
grate and placed in wagons, which were stored in a hay
shed at the Dairy Cattle Center during the feeding
study.