Efforts to replace some commodity acreage with specialty food crops have succeeded because of the pull of the market place and consumer acceptance of new foods. However, attempts to introduce new industrial crops, i.e., those with non-food uses, have been very slow, often haphazard, and inefficient. Intentional efforts in the last ten years to create new industrial crops and to discover new industrial uses for existing commodity crops have met with a modicum of success, acceptance, and support. More movers and shakers are seeing the value of this effort in reducing commodity surpluses while maintaining a strong agricultural economy and undergirding an industrial infrastructure for the future.
One small piece of this effort was advanced at a conference in Kansas City, MO, in December 1986, when a small group of university scientists, private sector representatives, and government scientists and managers focused on rapeseed and crambe (Crambe abyssinica) as candidate industrial crops for the U.S. (Carlson and Van Dyne 1992). Both crops produce seed oils rich in erucic acid (EA), which is used to manufacture a key additive for the plastics industry, erucamide, a slip and anti-block agent critical to manufacture and use of polyolefin films. Plastic films such as polyethylene are produced in a plethora of forms for such familiar items as bread wraps, shopping and garbage bags, and shrink wraps and plastic sheeting for an array of commercial applications. At the time of the Kansas City meeting, domestic needs for erucic acid were entirely satisfied by imports of high erucic acid rapeseed (HEAR) oil, originating largely in northern and eastern Europe and in Canada. This niche industrial market for high erucic oils had been known for over 20 years. As a source of edible oil, HEA (industrial) rapeseed had been introduced on a large scale to the North American continent in the 1960s and 1970s through the splendid research of Canadian agricultural scientists. Their equally elegant research converted the crop (1970s and 1980s) to low erucic acid cultivars (LEAR) and ultimately to canola cultivars without significant erucic acid content. With the widespread acceptance of LEAR and canola worldwide, HEAR oil appeared to be moving from a widely available commodity oil to a contracted specialty oil.
By December, 1986, the University of Idaho and the U.S. Department of Agriculture had conducted substantial research on rapeseed and crambe, respectively, and came to Kansas City with significant data bases relating to the production of the two crops in the U.S. However, annual production of several thousand ha of HEAR in Idaho, which was marketed to Pacific Rim countries, and very sporadic production of crambe, though funneled to domestic erucamide producers, had failed to instill confidence in either crop's reliability as a domestic source of erucic acid. Faced with a rather dismal marketing and production track record, participants at the meeting still recognized the potential of, and critical need for, erucic acid's industrial niche, and the significance of developing a domestic source of erucic acid. Thus was laid the groundwork for a high erucic acid development effort (HEADE), which would evolve into an informal consortium of university scientists, industry participants and government scientists and managers focused as a team on the commercialization of crambe and industrial rapeseed as domestic sources of erucic acid.
Table 1 lists the institutional partners and some areas of expertise that they brought to the HEADE project during the period 1986-95. Contributions made by each institution depended on the disciplines of numerous individual scientists, and ranged from chemistry, biochemistry and engineering to multiple aspects of plant, insect, and animal sciences to crop production and oilseed processing to technology transfer, marketing, and economics. Each contribution was critical to the evolutionary path that HEADE took in successfully bringing crambe to significant commercial production.
An annual line item appropriation from the Congress provided partial funding for HEADE activities (<$500,000). The funds were administered through the CSREES Office of Agricultural Materials (USDA) to the participating universities under cooperative agreements.
Each member university also provided funds and in-kind support for the research and commercialization projects. The HEADE management committee established RFP (request for proposals) and peer review procedures (filtered through the subcommittees) to select 15 to 20 projects for funding each year.
When line item funding for HEADE ended in FY 95, the HEADE management committee completed remaining funded research projects, and encouraged project members to continue their institutional commitments to crambe and rapeseed commercialization. Internal funding and development of cooperative interactions with seed, biotech and chemical companies and with growers groups have enabled several universities to continue breeding, agronomic, animal feeding, and chemical research on crambe and rapeseed. For example, North Dakota State University and the Universities of Georgia, Idaho, and Nebraska are funding projects through their plant and animal sciences, chemistry and engineering, and extension departments. Numerous companies and private sector individuals formally and informally partnered with HEADE, and their contributions were especially important to HEADE's decade of work to commercialize high erucic acid crops. The discussion that follows covers HEADE efforts on crambe seed production, meal utilization and renewed breeding studies.
In comparison to the cultivation of rapeseed, which is usually dated to the 20th century BC, crambe was introduced a little more than 50 years ago through a coordinated network of federal, state, and private interests. While still far from being considered a common crop, its path from potential crop designee to commercial production in such a short period of time has made crambe an interesting case in new crop development. During the rapid increase in crambe production in the 1990s, scientists at NDSU strove to reach beyond traditional small plot research to better identify why and how farmers respond to new crops, which ultimately determines whether they will be successfully incorporated into new farming systems.
Since this early promise was identified, various state and federal agencies have evaluated crambe for brief periods. North Dakota investigated crambe at several research centers in the late 1960s and early 1970s. Hoag and Geiszler (1970) reported a five year mean yield at Minot, ND, on fallow of 1698 kg ha-1. At Williston, ND, on dryland, a mean yield of 842 kg ha-1 was obtained during the same 1965-1969 period. In reporting results with crambe, North Dakota was no different than several other state and national efforts at the time, all exploring production feasibility (White and Higgins 1966). The majority of production research, however, came from the Midwest cornbelt and was championed by breeder Koert Lessman at Purdue University (Lessman and Meier 1972). Crambe appeared drought tolerant, widely adapted, and among the most promising of several potential new crops.
As with most crops, coordinating and balancing supply with demand has historically been a problem with crambe. The USDA initiated field production of crambe for several years in the late 1970s to build seed supply. This effort ultimately led to the first private sector promoted attempt to commercially produce crambe (Princen 1983). In the spring of 1981, 405 ha of crambe were contracted with Humko (now Witco Chemical Co.) to be grown in western Kentucky (Durwood Beatty pers. commun.). A price of 25 cents per kg-1 was agreed upon and the crop was seeded in March with the hopes of a late June or early July harvest in time to double crop soybeans. The warm, dry spring gave crambe a good start, but also resulted in a wide-spread aphid epidemic, which destroyed ca. 80% of the crambe plantings. Harvested seed was destroyed in a warehouse fire later that year. Such an egregious result left little private sector interest in crambe, and some observers at the time of the Kansas City meeting in Dec., 1986, questioned the wisdom of advancing the cause of high erucic acid crops for the U.S. However, others believed that a systems approach to breeding, production, processing and marketing of both industrial rapeseed and crambe was not only appropriate but a right avenue to successful domestication (Carlson and Van Dyne 1992).
Successful production of crambe in North Dakota has continued (Table 3), but not without difficulties. NSI's attempts to produce crambe in the Central Great Plains, near Goodland, KS and also in the San Luis Valley of Colorado in 1993 were disappointing, and commercial production of crambe remains concentrated in North Dakota. In North Dakota, production began in the central and eastern portions of the state, but wet conditions during the past few years have moved production west. Today, the three principal growing regions surround the counties of Barnes, Foster, and Stutsman in the central region, Ward in the northwest, and Hettinger in the southwest portions of the state. Despite attempts to balance supply and demand, over-production limited the 1995 crop to seed increase until oil stocks could be consumed. Also, NSI decided to leave the oilseed crushing business, and leased their processing facilities in late 1994. Perhaps as evidence of its success, HEADE also lost its federal funding in 1994. Therefore, North Dakota crambe growers have organized into the American Renewable Oil Association (AROA), which has taken on the responsibilities of crop production, seeking processing facilities, and marketing oil and meal. At the time of this writing, AROA anticipates 16,000 ha of crambe production in 1996 (7-9 million kg of oil).
Through a combination of formal surveys and informal observations, North Dakota crambe production practices have been documented in a series of reports published by NDSU (Gardner 1991-1995). Crambe, usually seeded in May and harvested in Aug., has typically followed a small grain crop in rotation (>85%), but also followed flax, fallow, and various other crops. Most growers rate the crop that followed crambe to have performed equivalent to, or better, than when that crop followed a small grain. Volunteer crambe is manageable in succeeding crops through either use of tillage, herbicides, or a combination of both; however, seed dormancy studies suggest that germination may be delayed for extended periods under field conditions. Crambe has been seeded successfully with a wide variety of planting equipment into tilled and untilled seedbeds. It is nearly always seeded into narrow rows (<20 cm) to increase it's ability to compete with weeds early in the season. Herbicides labeled and used are much the same as those used with canola, with soil-applied dinitroanalines applied pre-plant the most popular. The most troublesome weeds are often those that mature late, once the crambe crop is drying down. Though competition with these weeds may not directly reduce yield, it makes harvest more difficult. Crambe can be swathed to dry in the field, but most growers prefer to harvest crambe direct with combine headers commonly used with wheat. Unlike canola, crambe cannot be swathed before the majority of the seeds are physiologically mature, since erucic acid content of the oil is lower in immature seeds. Crambe stubble is easily managed, and requires little fall tillage. The residue is valuable to reduce wind erosion and is an efficient snow trap during the winter.
In comparison to other Northern Plains crops, crambe is relatively inexpensive to produce. Certified seed costs are generally less than $12 ha-1 for the typical 22 kg ha-1 seeding rate. The fertilizer requirements have been found to be no greater than wheat. Dinitroanaline and post-emergent grass herbicides currently labeled are also among the most inexpensive available. Insecticides have not been needed, since, unlike rapeseed or canola, crambe is resistant to flea beetles, the most troublesome insect pest among crucifers in the Great Plains (Anderson et al. 1992). During a typical harvest, crambe seed does not require drying, and due to it's low test weight, is easily aerated should moisture content need to be reduced for storage. Over all, crambe is easily grown with traditional wheat equipment.
Low test weight. Crambe, unlike rapeseed and most other crucifers, has each seed encapsulated in its own hull. This reduces test weight by more than 50%, to about 322 kg m-3 (25 lb bu-1). Such a bulky commodity increases the cost of transportation from the farmgate to the processing facility, and misleads the grower in visually estimating dockage, or foreign material, in the harvested seed. During the first year of commercial production, the overall mean dockage content of crambe delivered to the processing plant was 14.8%, significantly adding to already substantial transportation costs of the grower. This initially kept commercial production no further than 240 km from the processing plant. Since 1990, above average rainfall across North Dakota has shifted the production region west to avoid diseases such as Alternaria, which limited production in the eastern portion of the state for the first time in 1992. Greater distance from the processing plant has encouraged the grower organization to arrange for group rail shipments. Limited investigations into farmgate dehulling have been discouraging since it can lead to a reduction in oil yield and quality.
Seed dormancy and quality. Barely domesticated, it is not surprising that crambe exhibits a post-harvest dormancy. Such mechanisms are typical in undomesticated species to improve longevity and success. In an annual crop, however, such a trait makes it difficult to accurately estimate germination percentages and can lead to volunteer plants emerging in the field several years after the crop is harvested. Crambe has suffered from both problems. In addition, with abnormally greater rainfall the last few seasons, Alternaria has been observed among the eastern-most growers. Alternaria can infect the seed, causing a subsequent reduction in germination and vigor when later planted (Kilpatrick 1976). The growers group has responded to these problems through establishment of a network of certified seed growers, regular testing, and encouragement of further research at NDSU and elsewhere (Gutormson et al. 1993).
Pesticide availability. Like all new and minor crops, not only must new growers accept the risk of dealing with an unknown crop, but they must also do it with few, or no, labeled pesticides to help aid in weed, disease, and insect management. Current federal registration policies, and an industry that increasingly limits pesticide development even for the few major crops, combine to put new crops at a significant disadvantage in terms of production risk. Through the coordinated work of federal and state researchers, crambe has been coupled with rapeseed/canola in terms of federal pesticide registration, but this still requires the manufacturers to list the specific oilseed (canola, rapeseed, crambe) on the label (U.S. Govt. 1992). Perhaps foreshadowing a requirement for future new crops, crambe was successfully commercialized, because of its inherent ability to compete with weeds, ward off insects, and escape diseases without help from pesticides.
As a member of the mustard family of plants, crambe seeds and meal contain several glucosinolates recognized as sources of potentially antinutritional compounds. Similar compounds are responsible for the sharp flavors of certain condiments and food vegetables, such as radish, horseradish, cabbage, brussels sprouts, broccoli, and mustard. Of the glucosinolates in crambe, the major one accounts for ca. 95% of the total and is commonly called epi-progoitrin [(S)-2-hydroxy-3-butenyl glucosinolate]. These compounds and their metabolites may interfere with iodine metabolism by reducing the ability of the thyroid to take up iodine. Most reports conclude that oilseed meals containing glucosinolates reduce feed intake and animal performance when fed to non-ruminant animals, but ruminants tolerate glucosinolates at much higher levels without negative effects. Typical levels of individual and total glucosinolates found in commercially processed crambe meal, and in high and low glucosinolate rapeseed meals, are given in Table 8. Glucosinolate contents of defatted meals produced in the 1990s (50-60 µmol/g) generally were higher than in meals produced in the 1970s (25-45 µmol/g), although harvested 1990s seed had lower glucosinolate contents (90-100 µmol/g) than seed processed in the 1970s (125-155 µmol/g). Also, the one glucosinolate breakdown product consistently found in processed crambe meals, 1-cyano-(S)-2-hydroxy-3-butene, relates to glucosinolate destruction during processing and was present in 1990s meals at levels about one half that found in 1970s meals. These results suggest better process control and milder operating conditions in NSI's Enderlin mill during the 1990s, leading to nutritionally better products (Carlson and Tookey 1983; Carlson et al. 1985).
Crambe meal in ruminant diets. Since growth and profitability of crambe as a crop is limited by commercial acceptance and use of the meal as a feed component, positive results in recent HEADE promoted feedlot trials with commercial meals are highly encouraging (Table 4).
Feeding nearly 900 feedlot cattle in 1990 on the first NSI produced crambe meal, Stock et al. (1993) reported an initial decrease in feed intake, but within 3 days intake was equal to control animals. Slightly more crambe ration was consumed over the first 80 days on feed compared to controls, but slightly less over the last 40 days on feed. Duncan and Milne (1991) reported a 6 day adaptation period by ruminant microflora, which may or may not affect initial feed intake when glucosinolate containing meals are introduced to ruminant diets (Carlson and Breeze 1984; Darroch et al. 1991). Anderson et al. (1993b) found that beef cows offered only crambe meal did not consume it until mixed with as little as equal parts of any other feed, such as corn silage. Enhancing palatability of high glucosinolate meals with flavor enhancers has not been extensively studied, but Ingalls and Sharma (1975) reported a non-significant trend to increased intake with flavor or molasses added to high glucosinolate rapeseed diets. Also, no differences in intake of high glucosinolate rapeseed meal in diets based on grain sorghum were observed in steers (Heidker and Klopfenstein 1990). In addition to blending crambe meal with other feed components, pelleting the rations is important to prevent cattle from sorting diets (Lambert et al. 1970; Perry et al. 1979).
In a 63-day creep feeding trial (Table 4), crambe meal fed as a protein source in creep feed at 0%, 5%, and 10% did not affect feed intake, gain, feed efficiency, or thyroid hormones (T3 and T4) measured in blood serum of nursing beef calves (Anderson and Trautman 1995). Perry et al. (1979) previously observed that younger animals may have a higher tolerance for crambe meal. Comparison with more extensive feeding studies with high glucosinolate rapeseed are useful. Ingalls and Sharma (1975) reported that lactating cows were not affected by feeding high glucosinolate rapeseed meal at up to 10% of the diet. Papas et al. (1979) found that feed intake, milk yield, protein, fat, and solids were not affected by replacing soybean meal with rapeseed meal containing either 94 or 50 µmol/g of glucosinolates. However, the higher glucosinolate meal reduced iodine content of the milk and tended to reduce plasma thyroxine in cows. When calves were fed control, low, or high glucosinolate diets, feed intake, weight gain, hemoglobin blood cell volume, and erythrocyte count were unaffected except at the higher glucosinolate levels, which also resulted in more pronounced changes in the thyroids of the calves (Papas et al. 1979).
In two feedlot studies, Anderson et al. (1993a, b) compared four pelleted protein supplements using crambe meal as the protein source to replace 0%, 33%, 67%, or 100% of soybean meal. No differences were observed in feed intake, feed conversion, or rate of gain during an 84-day growing period with crambe meal fed at a maximum of 16.9% of dry matter intake and a 96-day finishing period with crambe meal fed at a maximum of 4.1% of dry matter intake (Table 9, combined feeding results). The growing period study utilized the highest published use level for crambe meal in preparing beef cattle for finishing at the prescribed FDA level of 4.2%. Beef cattle showed no adverse response to crambe meal at levels up to 8.5% in a previous study by Perry et al. (1979), using what is believed to have been a nutritionally inferior meal to the commercial meal used by Anderson et al. (1993a, b).
Earlier research, to support the petition to FDA to clear crambe meal for use in beef cattle rations (Federal Register 1981), determined that no glucosinolate products accumulated in beef fat or tissues (to 1 ppm) when dehulled, defatted crambe meal was fed to steers at 10% of their diets (Van Etten et al. 1977).
Effect of crambe meal on reproduction. Higher levels (25% to 32%) of crambe meal were used in yearling heifer rations than in most feedlot trials without detriment to ovarian cyclic activity or behavioral estrus. Long term studies with postpartum bovines, however, suggest a significant increase in days from calving to conception and increased services per conception with low levels of glucosinolate (31 g/day) in the diet (Cheeke 1987; Cheeke and Shul 1987). Lactating beef cows on 10% crambe meal produced equal calf gains and similar post partum interval to other protein supplement treatments (Anderson 1993). Pregnant ewes have shown no effect from high glucosinolate rapeseed meal on reproduction (Cheeke 1987; Cheeke and Shul 1987).
Implications. Crambe meal as currently produced will continue to be used in ruminant feeds (beef cattle), and be excluded from nonruminant feeds because of reported problems of growth depression, weight loss, toxicity, and organ pathology in monogastric animals (Hesketh et al. 1963; Van Etten et al. 1965, 1969; Fenwick et al. 1983; Wallig et al. 1988). An economical process for removal of glucosinolates and aglucons from crambe meal or low or no glucosinolate crambe germplasm would enhance the potential for use of crambe meal in nonruminant animal feeds. There is no assurance that breeding programs will develop low glucosinolate crambe cultivars. In fact, there are arguments for retaining glucosinolate levels in crambe, since they appear to play a role in crambe's insect resistance (Bell and Charlwood 1980). Research on crambe meal needs to continue with simultaneous basic and applied studies. For example, a series of trials conducted according to FDA guidelines to address the current restrictions for use of crambe meal are needed, wherein the first objective would be to increase the allowable use level or to remove the current limitation on use of crambe meal in feedlot beef cattle. A second objective would be to follow with clearances for crambe meal use in other phases of beef production. Research sponsored and encouraged by HEADE, and recent results obtained at NDSU, provides strong support for these objectives.
Campbell et al. (1986a, b) developed and released the cultivars, 'BelAnn' and 'BelEnzian', and the lines C-22, C-29, and C-37, by introgressing genetic material from wild populations into Indy. The five releases performed as good as or better than 'Prophet', 'Indy', and 'Meyer' in several locations.
Lessman continued his breeding effort at New Mexico State University during the 1980s and developed a group of elite lines that approached his earlier releases in performance. With Lessman's retirement in 1991, HEADE arranged to establish a crambe breeding program at North Dakota State University. Crambe germplasm gathered for the NDSU program included previously released cultivars, 103 accessions from the world collection maintained at the North Central Plant Introduction Station at Ames, Iowa, and breeding material from Lessman's Purdue and New Mexico State University programs.
Economically, crambe has also been advantageous. Investment in more equipment is not required, since crambe can be grown with equipment traditionally used to produce small grains. It is produced with a minimum of expense, and requires few pesticides. Being an industrial oilseed, crambe's price is somewhat independent of the traditional edible oilseed complex, thus offering farmers additional marketing alternatives. And, because of it's relatively low test weight, crambe will tend to be processed locally. In short, crambe has been a welcome addition to the repertoire of crops grown in the Northern Plains.
Crambe oil's major use in the well-defined erucamide market is welcome, but innovative research to develop additional markets is needed to sustain and expand domestic production of crambe and crambe oil. Perhaps the HEADE team's greatest disappointment was its inability to garner sufficient funding to pursue additional research and development in potential new product areas. The proprietary nature of some of the product development research sponsored by HEADE makes it inappropriate to discuss in this open forum. Also, though not discussed in this paper, HEADE sponsored some significant oilseed processing research, which aided the commercialization of crambe and has been or will be published elsewhere.
| Institutional partner | Contributions by discipline and acquired knowledge |
| USDA, CSREES, OIM | Management, oversight, budgeting |
| USDA, ARS, NCAUR | Management, chemistry, oil & meal processing, markets |
| University of Georgia | Rapeseed: breeding, production sciences |
| University of Idaho | Rapeseed: breeding, plant & animal sciences, crop production, economics |
| University Illinois | Animal science, marketing |
| Iowa State University | Crambe: plant science, processing, economics |
| Kansas Board of Agriculture | Marketing, economics, management skills |
| Kansas State University | Plant & animal science, processing |
| University of Missouri | Management, plant & animal science, economics |
| University of Nebraska | Plant & animal science, process engineering |
| New Mexico State University | Crambe: breeding, plant science, crop production |
| North Dakota State University | Crambe: breeding, plant and animal science, chemistry, marketing, extension service to growers |
| Organizational unit | Unit functions and responsibilities |
| Management Committeez | Provide leadership, establish budget, set priorities, allocate resources, coordinate research, promote communication, review progress, report results |
| Subcommittees: | |
| Production | Research and advice for: seed increase/certification, agronomy, plant diseases, insect & weed control, and breeding; commercial seed production assistance |
| Processing & Co-products | Research and advice for: seed preparation and oil extraction, oil and meal quality, meal feeding studies |
| Marketing & Economics | Market development, product development, economics, private sector interactions |
| Statistic | 1990 | 1991 | 1992 | 1993 | 1994 | 1995 |
| Hectares | 955 | 1,812 | 8,532 | 22,469 | 17,790 | 538 |
| Net yield (kg ha-1) | 1,456 | 1,499 | 1,275 | 1,132 | 1,456z | 1,568z |
| Net crush (tonnes) | 1,057 | 2,340 | 11,128 | 21,948 | nay | 0 |
| Foreign matterx (%) | 14.8 | 10.3 | 9.9 | 13.8 | na | na |
| Moisturex (%) | 8.5 | 9.0 | 9.6 | 10.4 | na | na |
| Test weightx (kg m3) | 327 | 341 | 332 | 324 | na | na |
| Oil yield (%) | 28.5 | 32.2 | 31.1 | 32.3 | na | --w |
| Meal yieldv (%) | 67.6 | 66.4 | 61.5 | 56.8 | na | -- |
| Seed oil (%) | 29.1 | 32.7 | 33.1 | 31.9 | na | -- |
| Meal moisture (%) | 8.8 | 9.5 | 8.3 | 9.6 | na | -- |
| Meal protein (%) | 32.1 | 30.4 | 30.5 | 30.5 | na | -- |
| Meal fiber (%) | 20.3 | 19.4 | 21.4 | 19.9 | na | -- |
| Erucic acid (%) | 57.2 | 57.6 | 57.1 | 55.3 | na | -- |
| Year | Study | Location |
| 1990-91: | Commercial feedlot study | Foxley Cattle Co. with UNE |
| 1991-92: | Feedlot study with WS | NDSU, Carrington, ND |
| 1992: | Pilot study, lactating cows | NDSU, Carrington, ND |
| 1992-93 | Feedlot study with DHS | NDSU, Carrington, ND |
| 1993: | Digestion study (high forage) | NDSU, Fargo, ND |
| 1993-94: | Creep feed, beef calves | NDSU, Carrington, ND |
| Content (% DM) | |||||||
| Defatted seed meal | Protein | Crude fiber | Crude fat | Acid deterg. fiber | Ash | N-free extract | Glucosinolates (µmol g-1) |
| Whole seed | 27.7 | 22.0 | na | na | 7.7 | 40.0 | 45-70 |
| Partially dehulled | 34.6 | nay | 0.8 | 34.7 | 8.4 | na | 56.0 |
| Totally dehulled | 49.5 | 6.5 | na | 7.5 | 9.9 | 35.5 | 80-100 |
| Mineral | Crambe mealz | Soybean mealy |
| Calcium (%) | 1.26 | 0.33 |
| Phosphorus (%) | 0.88 | 0.71 |
| Potassium (%) | -- | 2.14 |
| Sulfur (%) | 1.26 | 0.47 |
| Chloride (%) | 0.70 | -- |
| Magnesium (%) | 0.51 | 0.30 |
| Sodium (%) | 0.04 | 0.03 |
| Iron (ppm) | 110 | 142 |
| Boron (ppm) | 67 | -- |
| Zinc (ppm) | 44 | 61 |
| Manganese (ppm) | 43 | 32 |
| Copper (ppm) | 15 | 30 |
| Cobalt (ppm) | 1.35 | 0.10 |
| Selenium (ppm) | 1.07 | 0.14 |
| Content (g/16g N) DM basis | ||
| Amino acid | Crambe mealz | Soybean mealy |
| Alanine | 3.8-4.2 | 4.29 |
| Arginine | 5.7-7.3 | 7.27 |
| Aspartic acid | 6.0-7.6 | 11.78 |
| Cystine | 2.6-2.8 | 0.93 |
| Glutamic acid | 14.2-17.0 | 18.63 |
| Glycine | 4.7-5.3 | 4.30 |
| Histidine | 2.2-2.7 | 2.55 |
| Isoleucine | 3.7-4.1 | 4.58 |
| Leucine | 5.9-6.8 | 7.75 |
| Lysine | 4.9-5.7 | 6.43 |
| Methionine | 1.6-1.9 | 1.13 |
| Phenylalanine | 3.4-4.0 | 5.01 |
| Proline | 5.5-6.2 | -.- |
| Serine | 3.5-4.1 | 5.45 |
| Threonine | 3.1-4.6 | 3.93 |
| Tyrosine | 2.5-3.0 | 3.75 |
| Valine | 4.5-5.6 | 4.58 |
| Glucosinolate content (µmol g-1) | ||||
| Common name | Chemical name | Crambe mealz | HGRS mealy | LGRS mealx |
| Progoitrinw | 2-Hydroxy-3-butenyl | 56.3 | 22.5 | 5.2 |
| Gluconapin | 3-Butenyl | 0.3 | 31.2 | 4.5 |
| Sinigrin | Allyl or 2-Propenyl | 0.4 | -- | -- |
| Glucobrassicanapin | 4-Pentenyl | 0.8 | 22.9 | 3.9 |
| Gluconapoleiferin | 2-Hydroxy-4-pentenyl | 0.4 | 3.8 | 1.3 |
| Neoglucobrassicin | 1-Methoxy-3-indolylmethyl | -- | 12.3 | 12.5 |
| Total glucosinolates | 59.4 | 93.1 | 27.4 | |
| Crambe meal dietsx | ||||||
| Statistic | Control 100 SBw | 33 CM | 67 CM | 100 CM | Ureav | SE |
| Initial wt. (kg) | 294 | 294 | 294 | 293 | 294 | 2.44 |
| Final wt. (kg) | 520 | 540 | 538 | 520 | 529 | 4.15 |
| Avg. days on feed | 162 | 161 | 160 | 160 | 159 | 1.32 |
| Avg. daily gain (kg) | 1.40 | 1.53 | 1.52 | 1.42 | 1.48 | 0.09 |
| Feed/gain (kg/kg) | 2.97 | 2.84 | 2.91 | 3.06 | 2.95 | 0.57 |
| DM intake (kg/d) | 9.19 | 9.55 | 9.71 | 9.54 | 9.61 | 0.19 |
| Breeder/ Institution | Era | Results |
| K.J. Lessman Purdue Univ. | 1960s & 1970s | Prophet, Indy, & Meyer cultivars |
| K.J. Lessman New Mexico State Univ. | 1980s | Elite lines (possible male sterility) |
| T.A. Campbell USDA, Beltsville, MD | 1980s | BelAnn & BelEnzian cultivars |
| J.J. Hanzel North Dakota State Univ. | 1990s | Elite lines (possibly lower glucosinolates) |