- Two digestibility trials using sheep were conducted to determine
the digestibility coefficients of a commercially processed NaOH treated
annual ryegrass straw cube. Comparisons were made with loose, chopped
ryegrass straw and a ryegrass straw cube processed with molasses as a
The NaOH cubed straw was produced by spraying a solution of 30%
NaOH evenly over the straw and processing through a cuber. The resulting product averages 4% NaOH by weight. This treatment resulted
in significant (P < .05) increase in the digestibility of dry matter,
acid detergent fiber, and nitrogen-free-extract when calculated by
difference using chopped alfalfa. A trend toward increased digestible
protein and digestible energy was shown. Cubing with molasses did not
improve (P < .05) the digestibility of ryegrass straw when calculated
by difference. Digestibility of loose ryegrass straw was significantly
(P < .05) improved by the NaOH treatment with regard to dry matter,
crude protein, and acid detergent fiber when calculated "directly"
using urea and molasses.
The TDN (Total Digestible Nutrients) for the NaOH treated rye
grass straw cubes was 45.3% when calculated by difference and 44.4% when figured "directly". The TON values for the molasses cubes by
difference, plain straw by difference and plain straw "directly" were
39.7%, 41.3%, and 44.7% respectively.
The conclusion was made that this type of Na0H treatment of rye
grass straw resulted in significant improvement in its digestibility
when fed to sheep.
A third digestibility trial was run to determine digestibility and
nutrient composition of a dried bakery product (DBP). This product is
produced from nonsaleable bakery products which are mixed, dried, and
ground. DBP is primarily fed to dairy cows when used in the Northwest.
Digestibility was calculated by difference using "typical" dairy ration
components. Nutrient composition (%) of the DBP for crude protein (CP),
ether extract (EE), ash, acid detergent fiber (ADF), nitrogenfree
extract (NFE), organic matter (OG), calcium, and phosphorous were, respectively, 10.4, 8.5, 3.8, 1.8, 75.5, 96.2, .036, and .088. The gross
energy was 4.29 Kcal/g. The digestibility of these components when fed
at 20% and 40% of the diet, respectively, was (%) DM, 94.5, 93.4; CP,
82.4, 80.1; EE, 84.7, 84.4; OG, 64.5, 88.9; ADF, 99.7, 89.7; NFE, 97.7,
94.3; and GE, 95.8, 90.6. The digestibility coefficients were not sig
nificantly (P < .05) different when fed at the two levels, but a trend
was noted of lowered digestibility when fed at the higher level. TDN
values at the 20% and 40% levels were 93.1% and 88.0%, respectively.
It was apparent that the possibility exists that the DBP could be
increasing the digestibility of other ration components.