Crambe meal has potential for feeding ruminants, and inclusion rates up to 50% have been proposed (Göhl, 1982). However, the presence of antinutritional factors may limit its use.
Digestibility and degradability
The in vitro DM digestibility of crushed crambe and crambe meal were respectively 62 and 59% in steers. Protein degradability in crambe meal was lower than in crushed crambe, which suggests that crambe meal could be considered a source of rumen undegradable protein in cattle diets (Goes et al., 2017). In a comparison of 5 oilseeds, properly dehulled and defatted crambe meal was reported to have the highest potential degradability. Potential rumen degradabilities of OM for crambe meal and crambe cake were 96 and 73% respectively while it was 85% for rapeseed meal (Liu et al., 1994a). Total tract digestibilities of protein in dairy cows were 98% and 95% for crambe meal and crambe cake, respectively, while it was 92% for rapeseed meal (Liu et al., 1994a). The NEL (net energy for lactation) contents of crambe cake and meal were analysed to be 7.2 or 6.0 MJ NEL/kg DM for cows (Kampf et al., 2001).
Cattle
Dairy cattle
When included at 30% in concentrates, crambe by-products resulted in a decreased intake of concentrates in dairy cows. Milk yield decreased correspondingly (Kampf et al., 2001). A former study had shown that dairy cows fed ad libitum on grass silage had reduced feed intake and lowered milk yield when crambe meal or crambe pellets were included at 30% of the diet. Crambe pellets had deleterious effects on milk fat level and resulted in 2% erucic acid in milk fat (Kampf et al., 1999).
Steers
In crossbred steers given different combinations of soybean meal and crambe meal (100:0, 67:33, 33:67, 0:100) in backgrounding or finishing diets, the crambe meal resulted in similar animal performance as soybean meal with no difference in weight gain (overall 1.41 to 1.46 kg/d), no difference on feed conversion effciencies and other average efficiencies and no difference on carcass characteristics (Anderson et al., 1993).
Sheep
Crambe meal/cake is a valuable protein source for ruminants that has been assessed to replace soybean meal in lamb diets in Brazil (Itavo et al., 2016; Canova et al., 2015). Crambe cake with high fat content (29%) replaced soybean meal at 0, 22, 44 and 64% in lamb diets without affecting animal health (Canova et al., 2015). Crambe cake inclusion, however, resulted in a linear decrease of DM, OM, EE, gross energy, ADF, NDF, cellulose digestibilities and of the percentage of total digestible nutrients, which resulted in decreased daily DM intake. Nonetheless, the high fat and protein contents of crambe cake allowed high energy and protein intakes. The high fat content reduced methane emissions in lambs (Canova et al., 2015).
In lambs fed on extracted crambe meal containing less than 5% fat at inclusion levels ranging from 6% to 19%, DM intake was reported to increase while digestibility and lambs weights were not affected by crambe meal inclusion. Feed efficiency was thus reduced. Feeding crambe meal had no effect on carcass yield, carcass quality or meat juicyness (Itavo et al., 2016). The inclusion of crambe meal could reduce saturated fatty acis and increase unsaturated fatty acids in lamb meat (Itavo et al., 2016).