Canola meal: The new gold standard in protein evaluation studies for dairy cows
The results from four meta-analyses showed canola meal can be expected to raise milk yield and milk persistency when compared to other vegetable proteins.
By Essi Evans, Ph.D., E+E Technical Advisory Services
There’s a new sheriff in town when it comes to livestock feeding trials. Canola meal’s performance results have many researchers considering it the new gold standard when evaluating vegetable protein options for lactating dairy cow diets.
The results from four meta-analyses (studies in which data are combined from many experiments) showed canola meal can be expected to raise milk yield and milk persistency when compared to other vegetable proteins.1
While researchers continue to investigate why milk production generally exceeds expectations, some proposed explanations revolve around the efficiency of protein use, which is higher than many other vegetable proteins, as well as lower levels of methane production, resulting in greater usable energy than expected from ration-balancing programs.
With greater performance expectations, canola meal is giving soybean meal a run for its money with some researchers turning to canola meal as the protein standard with which to compare other proteins.
Fishmeal
Fishmeal has an excellent amino acid profile with respect to cows’ needs for milk production,2 but is generally too expensive to feed commercially. To determine if diets with fishmeal could permit reduced levels of canola meal, a feeding trial3 was conducted comparing the replacement of an equivalent amount of protein provided by canola meal at 50% or 100% with protein from soybean meal.
Results showed milk yield and milk protein yields were greater when canola meal was provided to the cows (Table 1). Intakes were similar for all groups, and canola meal supported body condition as well as milk production. Results also showed fishmeal may have raised the quality of the soybean meal diets.
Dehulled hemp meal
Another trial was conducted to evaluate a novel product: dehulled hemp meal.4 This meal is produced by extracting oil from hemp seeds and then sifting out the hulls, resulting in a product with over 55% protein and fiber levels, similar to solvent-extracted canola meal.
The control diet provided 15% canola meal. On a weight basis, the researchers either replaced half or all the canola meal with dehulled hemp meal for the two test diets. This resulted in more protein for the test diet than for the control diet.
Replacing canola meal with dehulled hemp meal resulted in diets with greater levels of crude protein, but which provided similar, but numerically lower, levels of milk and similar dry matter intakes. Milk urea nitrogen (MUN) was elevated when the cows were given test diets with the dehulled hemp meal (Table 2).
Extruded soybean meal
A third feeding trial considered the replacement of canola meal with extruded soybean meal.5 Extruded soybean meal is produced by forcing soybeans through a die at high temperatures, thereby resulting in a product with greater rumen undegraded protein than traditional soybean meal. Extruded soybean meal has more protein and fat than canola meal. The test diets were balanced to the same crude protein levels. Oil was added to the canola meal diet to balance the levels of fat.
In this trial, researchers determined the degradability of the extruded soybean meal was 50%, which compared favorably to canola meal at 55% using an older method of determination.
The researchers also determined that dry-matter intake, milk yield and milk protein yield values were similar for the two test diets (Table 3). Milk fat yield was higher when the cows were given the diet with extruded soybean meal.
Canola meal as the gold standard
The use of canola meal as the control in these studies provides insight into and understanding of how dairy cows use alternative sources of protein to support production. The wealth of research available related to canola meal provides a high level of confidence when using canola meal as the control in these evaluations. Using canola meal as the new gold standard may improve our understanding of other protein ingredients for dairy cows.
Data Summary Tables
References
1 Canola Council of Canada. Canola meal dairy feeding guide, 7th edition. 2024. https://76de0712.flowpaper.com/2024CanolaMealDairyFeedingGuide/#page=1
2 Abu-Ghazaleh AA, Schingoethe DJ and Hippen AR. Blood amino acids and milk composition from cows fed soybean meal, fish meal or both. J Dairy Sci 2001;84(5):174–1181.
3 Mohammadi F, Firouzabadi MSS, Savari M, et al. Replacement of soybean with canola improves short-term milk yield and nitrogen-use efficiency in high-producing, early-lactation Holstein cows. S Afr J Anim Sci 2023;53(5):649–657.
4 Addo F, Gervais R, Ominski K, et al. Comparing dehulled hemp meal and canola meal as a protein supplement for lactating dairy cows. J Dairy Sci 2023:106(12):8670–8683.
5 Cueva SF, Räisänen SE, Wasson DE, et al. Production effects of extruded soybean meal replacing canola meal in the diet of lactating dairy cows. J Dairy Sci 2023;106(9):6198–6215.
Data Summary Tables related to this research are on the next page.
