Abstract
Abstract Idaho’s sugar beet industry currently ranks 2nd in the United States producing 6
million tons of sugar beets on 175,000 acres. Processing sugar beets creates by-products
dairies can use as a feed ingredient. Common by-products are beet pulp, beet shreds (wet and
dried) and beet molasses. However, these by-products are mostly devoid of sugars following
commercial extraction, and the sugar content which remains is highly variable. The goal of
the proposed work was to produce high quality silage from ground/chopped fresh sugar beets
and incorporate the silage into a ration for lactating dairy cows.
Producing good quality silage from sugar beets is a challenge as they are wet (20
28% total DM), high in sugar (76% DM), and low in fiber (6.25% NDF on a DM basis).
These qualities enhance the probability of creating ethanol during silage production instead
of lactic acid necessary to properly ensile feed for cattle. To limit the production of ethanol,
additional substrate material (4% chopped oat hay, 27% ground corn, 16% ground wheat;
percentages as is) was added to ground sugar beets (53% fresh ground sugar beets, as is)
before ensiling in an oxygen-limited ag bag for a 90-day fermentation period. Samples of the
silage material were obtained and assessed over time for compounds critical in silage
production. Concentration of lactic acid increased from 0% to 2.53% DM over the 90-d
fermentation; while the sugar concentration was reduced and the NDF remained mostly
constant. Ethanol was present but remained low (< 2.5% DM) and of little concern.
After 90 d, the sugar beet silage was incorporated into a ration for lactating cows.
Using the Cornell net carbohydrate protein system (CNCPS) to balance key nutrients like
protein, fiber, sugar, and starch; a 60-day feeding trial began using two pens of lactating
Holstein cows consisting of a total of 377 cows (193 treatment, 184 control) balanced for
parity and days in milk (DIM). Four milk tests were collected during the trial to determine
milk yield along with composition. The first milk test was completed 4 days prior to the
incorporation of the treatment ration (sugar beet silage included) to one pen followed by 4
milk tests over the 60-d feeding trial. Milk production remained high in both pens for the
duration of the feeding trial. No differences in milk yield or milk components were found
between the pens during the feeding trial. Control animals maintained milk production of 108
pounds of energy corrected milk (ECM) with and average component yield of 3.87% butter
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fat and 3.27% protein, while the treatment animals produced 109.5 pounds of ECM and
3.87% butter fat and 3.30% protein yield.
Addition of oat hay, ground corn, and ground wheat to ground sugar beets led to
successful production of silage, which supported milk production in high producing dairy
cows. The cost of the treatment ration with sugar beet silage was less than the control ration
suggesting an economic benefit for production and inclusion of modified sugar beet silage in
lactating cow rations in Idaho.