Few studies have been conducted on presscake. Crossbred calves (4 to 5 months old) were fed RSM oil cakes as their sole protein source and DMI and ADG were 4.13 kg and 428 g/d, respectively. The RSM cakes did not affect the thyroxine concentration (Tyagi and Singhal 1993 {892}). Rapeseed meal cakes replaced SBM in increasing amounts up to 4 kg/d or 0, 25, 50 and 75% in the mixture in dairy cows rations. Performance did not differ between the two protein sources or for different levels of cake inclusion. An increase in butter quality with presscake inclusion has been reported (Christensson 1985 {1197}). Positive results were also reported by Christensen (1986 {1173}) and Frank (1981 {1258}).
Hulls make up 16% of the whole canola seed and 30%
of CM (Bell 1993 {907}). Mitaru et al. (1982 {1256}) reported
canola hull composition of the CM variety Tower to be 89.04% DM,
57.26% ADF and 28.87% ADL and variety Regent 89.30% DM, 51.94%
ADF and 26.55% ADL. Bell (1984 {1232}) reported that hulls proximate
analysis was 12-16% CP, 44% CF, 3% EE, 4-5% ash and 34% N-free
extract. Canola hull GE was 4.23 Mcal/kg DM. Gupta et al. (1987
{1138}) reported a higher CP % (22.3 to 28.2%), similar ADF, 55.0
to 64% NDF and variable lignin (14.6 to 31.8%) on four different
CM varieties. The chemical composition of canola hulls obtained
after a front-ended dehulling procedure contained 88.3% DM, 15.4%
CP, 46.7% ADF, 65.8% NDF, 4.1% Ash, 13.0% EE and 0.9% ADIN. Ammoniation
or solvent extraction of the hulls increased (P < 0.05) CP,
NDF and ADIN levels. Inclusion of canola hulls in alfalfa-based
diets of growing lambs reduced DM intake (P < 0.002) and apparent
nutrient digestibility (P < 0.05). Lambs fed 75% hulls had
a reduction in DM intake of 24% in comparison to the control.
Apparent protein digestibility of canola hulls for sheep was
estimated at 38% and a DE value of 9.3 MJ kg-1 DM was
reported. The low apparent protein digestibility indicates that
a large proportion of the hull protein is unavailable to the ruminant
animal. Ammoniation or ammoniation and solvent extraction did
not improve the effective rumen degradability of the nutrient
fractions of the hull and would not be an effective method of
processing canola hulls for ruminants (McKinnon et al. 1995 {831}).
Canola screenings are the fine seed materials separated
during screening of canola seeds in the cleaning procedure prior
to crushing and oil extraction or export (McKinnon et al. 1988
as cited Wiesen et al. 1990 {1044}). The major components of
canola screenings are lamb's quarters (23.8%), stinkweed (22.5%),
canola seed (17.1%) and hoary alyssum (14.1%). The average relatively
constant chemical composition is 19.6% CP, 22.5% EE 28% ADF and
92% DM (Beames et al. 1986 as cited by Mustafa 1996). As a percentage
of the total fatty acid content, canola screenings contain 52.2%
oleic and 24.2% linoleic fatty acids (Wiesen et al. 1990 {1044}).
Feeding canola screenings up to 14% of the ration had no effect
on milk yield, milk fat or protein percentage, but on milk fatty
acid composition. Milk unsaturated fatty acids (oleic (28.6%)
and linoleic (3.1%)) for cows consuming the canola screening-based
diets were increased. Canola screenings are fairly digestible
by sheep and digestibility coefficients of DM, OM and CP were
60.2, 63.9 and 77.4%, respectively (Tait et al. 1986 as cited
by Mustafa 1996).
Total tract DM digestibility
was greater (P < 0.01) for low GL forage than for the high
GL-containing diet (81.5 vs. 76.9%, respectively) (Pearce et al.
1991 {984}). Conversely, Lancaster et al. (1988, {1083}; 1990
{1018}) reported that the high GL-RSM silage was more digestible
and promoted faster, more efficient growth than the silage made
from the low GL variety. Rate of growth (kg/d) was greater (P
< 0.01) for high vs. low GL (.46 vs. .36) and for 50% or 100%
inclusion in the diet DM (.52 vs. .31). The glucosinolates present
in the high GL-RSM forage produced no detrimental effects on digestive
function or growth of beef steers.
Canola meal is a different and higher quality product
than RSM. Canola meal is equivalent in most rations to SBM and
in some instances performance has been higher with the use of
CM vs. SBM. Canola meal's ability to replace SBM and other protein
supplements in most ruminant rations is evidenced throughout this
literature review. The use of CM may increase human nutrition.
Christensen, D. A. C. Dairy Handbook.
Chilliard, Y. 1993. Dietary fat and adipose tissue metabolism in ruminants, pigs and rodents: A review. J Dairy Sci. 76:3897-3931.
Mustafa, A. F. 1996. Ph. D Thesis.
Parker, G. 1992. Canola as a Feedstuff for Animal Use.
Van Soest and Fox, 1992. Discounts for net energy and protein-5th revision. P 40-68. In proc. Cornell Nutr. Conf. Ithaca, NY.