Canadians seem to have done the most thorough research on the uses of rapeseed (canola). Here's an example.

http://www.canola-council.org/meal7.html

Canola Meal
Canola Meal Feed Industry Guide


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Cattle Diets

Canola meal is widely used in cattle feeds. In dairy cattle feeds, it is considered to be a premium ingredient due to the high quality of its protein with respect to requirements for milk production.



Rumen Degradability



The rumen degradability of canola meal protein has been extensively studied. Table 1 provides a summary of the effective degradability of the dry matter and crude protein fractions of canola meal assuming a rumen turn-over rate of 5% per hour. Ha and Kennelly (1984) reported that the effective degradability of canola meal protein was 65.8%. Effective degradabilities of soybean meal and dehydrated alfalfa were 53.6 and 41.4%, respectively. Kendall et al. (1991) found that the effective degradability of canola meal averaged 51.5%. This compared to 59.1% for soybean meal. Cheng et al. (1993) reported that the effective degradability of canola meal was 62.5% with concentrate diets and 72 to 74% with hay or straw diets. Therefore, it is important when evaluating such results for ration formulation purposes to consider the type of diet into which the protein supplement is to be incorporated. Piepenbrink and Schingoethe (1998) reported a rumen degradability of canola meal of 53.1%.



Research at the University of Manitoba has focused on the digestibility of the amino acids present in canola meal. Kendall et al. (1991) noted that following 12 hours of rumen incubation, total tract digestibilities of amino acids present in canola meal approached 85% or greater. Considerable variation was noted between samples and between amino acids in the proportion degraded ruminally or absorbed postruminally. Boila and Ingalls (1992) reported that the amino acid profile of canola meal protein that bypasses the rumen was superior in valine, isoleucine, threonine, phenylalanine, serine, aspartate and alanine, relative to unincubated meal. The magnitude of the enrichment in the bypass fraction ranged from 14 to 33%.



The results, in combination with the data presented in Table 1, suggest that a sizable but variable fraction of the protein of canola meal bypasses the rumen. In light of the enriched amino acid content of the bypass fraction observed by Boila and Ingalls (1992), it would appear that canola meal provides an important contribution to both rumen microbial protein needs as well as to the digestible amino acids required for animal growth and lactation.