Canola: Guidelines for Feed Use

Canola either for silage or hay is not commonly used in Manitoba but can be a valuable feed option during drought or feed shortages. While canola and other brassica species (e.g., turnips, kale) are widely used elsewhere, certain precautions are necessary to ensure livestock health.
 
Variety Considerations
  • Modern canola varieties are safe for ruminants; glucosinolates are primarily a concern in traditional rapeseed and affect swine/poultry more than cattle.
  • Forage-specific canola varieties exist in some regions, but grain varieties can also be used for silage.
 
Canola Hay
  • Swath should cure to 16–18% moisture before baling, requires wilting time
  • Initial moisture: 75–80%, requiring extended drying (up to one week or 4-6 days).
  • Use mower-conditioners to speed drying but avoid excessive leaf/pod loss.
  • Baling with dew can reduce shattering losses.
  • Blackened swaths during curing do not affect palatability.
  Quality by Stage:
  • Late bloom to mid-pod: Comparable to good alfalfa;
    • Crude Protein: ~15%
    • TDN: 60.4%
    • ADF: 35.8%
  • Fully podded/stemmy: Similar to slough hay;
    • Crude Protein: ~10%
    • TDN: 49.8%
    • ADF: 45.9%
  Note: Stemmy hay often refused by cattle.
 
Canola Silage
  • Preferred method due to high moisture and reduced leaf loss.
  • Wilt to 60–65% moisture before ensiling.
  • Tips for better ensiling:
    • Use horizontal storage if moisture exceeds 70% to reduce seepage.
    • Layer canola with other silage crops (e.g., cereals) to balance moisture and improve feed mixing.
    • Apply bacterial inoculants to improve fermentation (oilseed crops are low in soluble carbohydrates)
Optimal Harvest Stage
  • Best stage: Early podding (after flowers drop) to when lower leaves begin to fall.
  • Earlier harvest: Higher energy and protein.
  • Near maturity: Feed value similar to straw; poor palatability.
 
Nutritional Quality and Feeding guidelines:
  • Introduce gradually over 7–10 days to prevent bloating and scours.
  • Limit canola forage to 50–60% of total daily intake.
  • Nitrates: Canola may accumulate high nitrate levels, especially under stress or high nitrogen fertilization. Ensiling reduces nitrates by 30–50%.
  • Sulfur: Canola contains 0.5–1.3% sulfur; NRC recommends total dietary sulfur ≤ 0.4% of dry matter.
    • Excess sulfur can reduce copper and selenium absorption, suppress appetite, and cause thiamine deficiency leading to polioencephalomalacia (PEM).
  • Typical nutritive values:
    • Crude Protein: 12–14% (up to 16%)
    • TDN: 55–60%
 

Canola Seed

Nutrient Composition
The value of whole canola seed is primarily determined by its protein and oil content. Protein levels are relatively stable even when seed is damaged by frost or weathering. In contrast, oil content is more variable because oil is one of the last components to develop during seed maturation.
  • Frost‑damaged seed fails to fully mature, resulting in lower oil levels.
  • Mature or near‑mature green seed retains higher oil content despite high chlorophyll levels.
Typical nutrient ranges (dry matter basis):
  • Frost-damaged canola:
    • 21–24% crude protein
    • 31–42% oil (dependent on maturity at time of frost)
  • More mature green canola (>65% green):
    • 27.7% crude protein
    • 44.9% oil
  • #1 Grade canola (average):
    • 22–23% protein
    • 44–46% oil
The presence of chlorophyll in the oil does not pose feeding concerns and has shown no negative impacts in poultry research. However, processing greatly improves feed value.
 
Digestibility Improvements with Processing
Feed Type
Digestibility (%)
Unprocessed Protein
Unprocessed Energy
Processed Protein
Processed Energy
20% frozen canola (pigs) – Bell, 1984
20
34
66
60
5% frozen canola (pigs) – Bell, 1984
12
32
62
61
Canola screenings (steers) – Pylot, 1999
57.08
51.51
68.16
61.53
Processing (grinding, pelleting, extruding) breaks the hard, small canola seed, allowing digestive enzymes to access nutrients.
For on‑farm grinding, a 1/8-inch or smaller hammermill screen is recommended, with 30–50% grain added to prevent plugging.
 
Whole Canola Seed in Livestock Diets
General Fat Considerations for Ruminants
In cattle and sheep, total dietary fat should typically remain below 5.5–6% of diet dry matter to avoid reduced fibre digestion and lower feed intake. Prairie-based diets normally contain 1.5–2.5% natural fat, allowing whole canola to serve as a safe, energy-dense supplement.
(Fat supplies 2.25× the energy of starch.)
 
Beef Cattle
Feedlot / Growing Animals
Whole canola seed may be included at:
  • Up to 20% of diet dry matter, provided total fat remains <6%.
Examples:
  • 10% inclusion if seed contains ~40% oil
  • 15% inclusion if oil content is ~27%
Wintering Beef Cows
Whole canola can be mixed with grain to supply:
  • Maximum 300–350 g of oil per cow per day
The additional protein supplied may reduce or eliminate the need for purchased protein supplements.
 
Dairy Cattle
High-producing dairy cows may benefit from added dietary fat for additional energy.
  • Whole canola can supply up to 400 g of added oil per cow per day
  • However, due to unsaturated fat effects on fibre digestion, levels above ~300 g/day are rarely required
  • Excessive inclusion may lower butterfat or reduce intake
 
Canola Screenings
Oilseed screenings, including canola screenings, are commonly used as an alternative feed source for cattle. Their incorporation into rations is often limited by their high fat content (20–23%), as dietary fat levels above 5% can reduce fibre digestion and depress feed intake.
Research Summary
A University of Saskatchewan study (Can. J. Anim. Sci. 80:153, 2000) evaluated how increasing dietary fat levels—supplied through processed (ground and pelleted) canola seed screenings—affect voluntary feed intake in growing steers.
Dietary Treatments & Intake Results
Dietary Fat Level (%)
Dry Matter Intake (% of Body Weight)
6.7%
2.26%
10.0%
2.29%
12.8%
2.10%
16.2%
1.83%
Key Findings
  • Steers maintained normal intake at dietary fat levels up to 10% when fat originated from canola screenings.
  • Intake declined progressively when fat levels exceeded this threshold.
  • This indicates that canola screenings can be safely included in growing steer diets up to the point where total dietary fat reaches 10%, provided the screenings are processed to improve digestibility.
Practical Implications
Producers can use processed canola screenings as a high‑energy feed ingredient, while ensuring:
  • Total dietary fat remains ≤10% for growing steers.
  • Screenings are ground and/or pelleted to enhance nutrient availability.
  • Rations are balanced to maintain fibre digestibility and overall intake.