Chemical Composition, Digestibility and Performance of High and Low Fiber Canola Meal
Tail-end dehulling canola forms two fractions, low
fiber CM (LFCM 40%) and high fiber CM (HFCM 60%). This technique
involves tempering, disc milling and sieving of regular CM. Significant
differences in chemical composition, ruminal nutrient degradability
and intestinal protein availability of the resulting HFCM and
LFCM fractions. Tail-end dehulling resulted in a LFCM with higher
protein (40.2 vs. 37.7%; P < 0.05) and lower NDF (24.6 vs.
26.7%; P < 0.05) and ADF (14.4 vs. 19.3%; P < 0.05) content
and improved nutrient availability (78.4 vs. 89.3%; P < 0.05)
compared to regular CM. The HFCM fraction contained a lower protein
(35.2 vs. 37.7%; P < 0.05) and a higher fiber, particularly
ADF (23.9 vs. 19.3%; P < 0.05), content and reduced nutrient
availability (72.0 vs. 78.4%; P < 0.05) (Mustafa et al. 1996
{2061}). Lambs were fed 0, 250, 500 and 750 g/kg CM or HFCM.
With increasing amounts of HFCM FI decreased linearly (P <
0.05) and this was due to the high dietary intake of acid detergent
lignin (ADL). Feeding HFCM to lambs reduced total tract CP and
GE digestibility and a lower DE value was calculated (3% lower
than CM). However, dairy cattle supplemented with SBM, CM and
HFCM (17% CP DM) had similar milk production (33.6 kg/d), milk
fat (30 g/kg), feed intake (19.9 kg/d) and body weight gain (BWG).
Canola based diets reduced milk protein compared to SBM. This
was attributed to higher dietary CP in the SBM treatment. HFCM
can be included in dairy rations up to 100 g/kg DM without adverse
effect on milk yield or milk composition compared to CM (Mustafa
et al. 1997 {794}).
The Value of Canola Meal as a Feedstuff for Ruminants
Canola meal contains up to 40% CP (DM) and is
the leading protein source in Canadian beef and dairy cattle rations
(Christensen and McKinnon 1993; Moshtaghi Nia and Ingalls 1995
{827}). Several reviews have been published on the composition
and nutritive value of CM (Bell 1993 {907}; Bell 1984 {1232};
Bruckner and Mieth 1984 {1234}).