Written by: Buthaina Al-Maqtari & Akim Omokanye,
Location: Bill Fevang's Farm - High Prairie
From: Peace Country Beef & Forage Association 2019 Annual Report
Depending on the types of crops in a cover crop cocktail, a cocktail can have great forage potential in the Peace River region. Such a cocktail could improve water and soil quality, nutrient cycling, moisture conservation, and crop productivity when used in crop rotation systems. A multispecies annual crop mixture can be selected from a diversity of crop groups (e.g. grasses, legumes, broadleaves and forbs). Each crop species in a mixture may reach maturity at slightly different times, therefore providing green forage continuously throughout the growing season.
Methods
The study site was at Bill Fevang’s farm in High Prairie. The site had canola the year before and it was sprayed with a pre-seed burnoff before seeding the cocktails in 2019.
Experimental Design: 14 cover crop cocktail treatments were seeded (See Table 1 below) and arranged in Randomized Complete Block Design with 4 replications.
Seeding date was on June 7.
The seeds were sown using a Fabro plot drill equipped with disc-type openers on 9” row spacing. Six rows that were 8 m long were sown per plot. Seeding depth was 0.75”.
Fertility (actual lbs/acre): No fertilizer was applied.
In-crop herbicide application was not applied, instead hand weeding was carefully done twice during the growing season.
Harvesting for forage dry matter (DM) yield determination and quality analysis was done on August 28. Forage samples were sent to A & L Laboratory in Ontario for quality determination.
Results
Forage Protein - The forage CP was lowest for cocktail #13 (8.70% CP), while cocktail #1 had the most forage CP with 18.8% (Table 2). With the exception of cocktails #4 and #13, which both had 10% CP or less, cocktails mostly had >11% CP. This shows that both cocktails #4 and #13 with 8.7 - 10.0% CP would only be considered to provide enough CP for dry gestating beef cows. All other cocktails had adequate CP for mature beef cattle at all different physiological stages (pregnant and lactating). It is important to note that most cocktails also exceeded the recommended 12 - 14% for backgrounding and finishing calves.
Forage Fiber and Lignin content - The forage fiber content, ADF and NDF, is a strong predictor of forage quality, since it is the poorly-digested portion in the cell wall. The forage ADF, NDF, and lignin were lowest for cocktail #6. Other cocktails mostly had significantly higher ADF, NDF and lignin values than cocktail #6 (Table 3). Considering that as ADF and NDF increase, both digestibility and consumption of forage usually decrease. If cocktails are presented side by side to cows in a preference study, cocktail #6 would likely be consumed more.
Forage Energy - The forage total digestible nutrients (TDN) was highest for cocktail #6 with about 75% TDN (Table 4). Except for cocktails #1 and 7, which had less than 60% TDN, the cocktails had sufficient %TDN (60% TDN) for a dry gestating beef cow in both mid-pregnancy and late-pregnancy. Five of the cocktails (cocktails #1, 3, 6, 9, 10 and 13) had sufficiently met the recommended 65% TDN for mature lactating beef cattle.
Minerals - The forage Ca content was highest for cocktail #7 (2.41%) (Table 5). Only 2 (cocktails #4 and 13) of the 15 cocktails were not able to meet the 0.58% Ca needed by mature beef cattle. Other cocktails far exceeded the 0.58% Ca that has been recommended for mature beef cattle. On the other hand, cocktails #4 and 13 only had sufficient Ca for a dry gestating beef cow.
Overall, cocktails #2, #3, #7 and #8 were the only mixtures that had sufficient macro (Ca, P, K, Mg, S, Na ) and trace minerals (Cu, Fe, Zn, Mn) for mature beef cattle. Other cocktails when used for beef cattle would require free choice minerals.
Conclusion
The trial demonstrated that growing the right annual crop mixture can improve forage quality and provide beef cattle with a diet that in most cases is able to adequately meet the nutritional requirements for gestating beef cattle.
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