This study examined the nutritional value of canola hulls for ruminant
s and the effects of processing on in situ ruminal nutrient disappeara
nce. VI and apparent DMD, CPD, ADFD and NDFD (%) and DE content (MJ kg
(-1) DM) of canola hull supplemented diets were determined in a total
tract digestibility trial using 12 ram lambs. The dietary treatments w
ere 100% alfalfa hay; 75% alfalfa hay: 25% canola hulls; 50% alfalfa h
ay: 50% canola hulls; 25% alfalfa hay: 75% canola hulls. In situ disap
pearance of treated and untreated canola hulls was determined using tw
o fistulated cows. Processing treatments included: untreated hulls; am
moniation; solvent extraction; and ammoniation and solvent extraction.
As canola hull inclusion rate increased, DM intake, DMD, CPD, ADFD an
d NDFD decreased (P < 0.05) linearly. Digestible energy values did not
differ between diets, suggesting that canola hulls have a DE value (9
.3 MJ DE kg(-1) DM) similar to the alfalfa hay used in the trial. Rumi
nal nutrient disappearance and kinetic parameters were not improved by
ammoniation or solvent extraction. It is concluded that supplementati
on of canola hulls to alfalfa based diets will reduce nutrient digesti
bility and DM intake when fed to growing ram lambs. Ammoniation is not
an effective treatment for improving in situ nutrient disappearance f
rom canola hulls.