Forages are crucial to the sustainability of the livestock industry in Alberta. Over the years, producers have relied on a plethora of annual and perennial forage crops to supply feed for their farm animals. Although many traditional annual forages such as barley, oat, and triticale have been tested and used in animal feeding, there is still the need to focus on alternative forages of brassicas, forbs, and warm-season crops such as sorghum and millet which can equally complement the feeding regimes of producers. There is a concerted effort by PCBFA to examine non-conventional forage-type plant species as they become available. Such effort is geared toward collecting data on their agronomic performance, yield, and nutritional values under the Peace Region's local conditions.
The objective of this field trial was to evaluate the agronomic performance, DM yield and feed quality of 3 cool-season grasses, 2 forbs, 5 warm-season grasses, 4 brassicas, and a legume.
How we evaluated the alternative forage-type crops
The study was carried out at Garth Isaac’s farm in Teepee Creek (Hwy 733 and Hwy 674). The previous crop at the site before seeding in June 2022 was wheat.
The crops were arranged in randomized complete block design in 4 replications. Table 18 shows the crops seeded and their respective seeding rates.
Our Findings
Forage Dry Matter (DM) Yield
Forge DM yield ranged from 1,040 lb/ac for Pearl millet to 4,972 lb/ac for AB Tofield barley. In general, cool-season forage crops had the highest DM yield, while warm-season annual grasses were the lowest in terms of forage production. However, the 3 lowest producing treatments, NSB Sorghum Sudangrass, plantain, and NSD BMR Sorghum Sudangrass produced DM yield above 1,000 lb/ac (Table 19). Comparing the AB Tofield barley to Pearl millet, the former produced 3,932 lb/ac of forage over the latter, confirming the poor adaptation and productivity of Pearl millet in the Peace Region (Table 19).
For the forbs and brassicas, phacelia produced 3,722 lb/ac of forage making it the second highest treatment followed by the forage radish and chickling vetch with 3,700 and 3,569 lb/ac, respectively.
Overall, the cool-season annual grasses ranked 1st, followed by brassicas (2nd), legume (hairy vetch, 3rd), forbs (4th), and warm-season annual grasses (5th).
Forage Quality
Forage Crude protein (CP) content - The forage CP ranged from 6.9% for Bunker triticale to 18% for Akela forage rape. Plantain produced the second-highest CP content (17.7%). Except for Akela forage rape, other brassicas produced similar CP content, approximately between 15.3 and 15.8% (Table 19). For warm-season grasses, only Pearl and Japanese millet produced CP content greater or equal to brassicas (15.8 and 15.9%). Overall, cool-season grasses did not contain adequate CP to meet the requirements of all classes of cattle, while brassicas, forbs, legume, and warm-season grasses had adequate CP content for dry gestation and lactating cows. Evidently, CP content in forages was in the order of brassicas>forbs>warm-season grass>legume>cool-season grass was observed.
Neutral detergent fibre (NDF) and Acid detergent fibre (ADF) - NDF ranged from 32.7% for Akela forage rape to 61.5% for NS B Sorghum Sudangrass while ADF ranged from 23.4% for AB Tofield barley to 38.5% for NS B Sorghum Sudangrass. The Akala forage rape had the best NDF of 32.7% while AB Tofield barley was the best in ADF with 23.4%. Generally, warm-season grasses were higher in both NDF (between 54.2 and 61.5%) and ADF (between 32.8 to 38.5%). This indicates that forage consumption and digestibility by cattle will be limited due to the higher fibre content in these grasses. In addition, both phacelia (44.5%) and plantain (43.8%) were better in NDF compared to all cool-season grasses but were similar in NDF contents (Table 19). However, the NDF (41.9%) and ADF (31.7%) of chickling vetch were better than both forbs and warm-season grasses.
Total digestible nutrients (TDN) - The forage TDN measured as a form of energy was different for all the treatments in the study. Except for NS B Sorghum Sudangrass (59.1%), the %TDN was mostly above 60%. The AB Tofield barley had the highest TDN (70.8%) while NS B Sorghum Sudangrass had the lowest (59.1%). Overall, cool-season grasses were higher in %TDN than warm-season grasses and forbs while the chickling vetch (64.2%) was also higher compared to forbs. Generally, the %TDN of treatments is adequate for matured beef cattle (55-65%) for either pregnant or lactating cows and 65-70% for calves.
Minerals - Calcium (Ca) content varied from 3.4% for phacelia to 0.3% for Bunker triticale. Notably, Ca content was lower in both cool and warm-season grasses compared to brassicas, legume, and forbs (Table 20). This result indicated that all treatments met the Ca requirements in diets for lactating cows (0.31%), dry cows (0.18%), and calves (0.58%).
Phosphorus (P) ranged between 0.25 and 0.11%. The forage radish had the highest (0.25%) while NS B Sorghum Sudangrass had the lowest (0.11%). Generally, cool and warm season grasses had the lowest levels of P while brassicas, legume and forbs were high (Table 20). Nevertheless, only brassicas and the plantain forb (≥0.21%) met P requirement for lactating and dry cows (0.16%) but not growing calves (0.26%). Forbs, legume, and CDC baler oats met the P requirements for dry cows but did not meet the needs of both lactating cows and growing calves. Furthermore, Potassium (K) contents varied between 3.0% for forage brassica vivant and 1.1% for Bunker triticale. All tested crops were adequate to meet the K requirement of both lactating cows (0.60%) and growing calves (0.70%). Magnesium (Mg) was generally higher in all forage crops tested except for Bunker triticale (0.19%) which was slightly deficient. Sodium (Na) on the other hand was lower in legume, phacelia, and all warm-season grasses. However, all cool-season, brassicas and plantain forage crops were adequate in sodium for all classes of cattle.
Relative feed value (RFV) - The RFV was highest in both Akela forage rape and forage brassica vivant (213.0, respectively) and lowest in NS B Sorghum Sudangrass (89.0). With the exception of forage radish (130.0), brassicas were superior in RFV to all other forage crop treatments. However, cool-season grasses, legume, and forbs had better RFV compared to warm-season grasses (Table 19). Overall, brassicas ranked as 1st, legume as 2nd, cool-season grasses as 3rd, forbs as 4th, and warm-season grasses as 5th. This result indicates higher expected consumption and digestibility of brassicas compared to other forage treatments in the trial.
Conclusion
This trial demonstrated that cool-season grasses (barley, oats, and triticale) are high-yielding forage compared to other forage crops tested. However, it was also noted that brassicas, legume, and the phacelia forb can equally do well in forage yield. The lowest producing forage treatments were warm-season grasses confirming their poor adaptability and growth in the Peace region. Though cool-season grasses were better at biomass yield it was the poorest in nutritional qualities such as CP content, while brassicas, legume and forbs were better in feed nutritional value. Minerals were also adequate in all forage crops tested; however, it is recommended that free-choice minerals be supplied through feeding in their right proportions to ensure better absorption and utilization by cattle.
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