Site: High Prairie Airport
Research Coordinator: Dr. Akim Omokanye
Observations Following Cutting Treatments
Thirty two perennial forage species and varieties were established in June 2010 (Table 1). Establishment procedures and progress were presented in the PCBFA 2010 Annual Report and are also available on the ARECA website www.areca/members/PCBFA.html. The perennial forage demonstration plots are being used for assessing new forage varieties for adaptation to parts of the Peace, tolerance to drought, winter hardiness, recovery after cutting and potential for multiple cuts, over a 5-year period. With this trial, farmers will be able to appraise for themselves both traditionally grown and new forage species that have been developed and released in recent years. This report outlines the second year’s progress, with focus on forage DM yield and quality following different cutting dates.
The demonstration plots are located at the High Prairie Airport. The varieties were observed for winter kill early in the spring. The grasses received 75 lb N using urea.
Each forage variety plot was divided into 3 sections, each measuring 2.5m x 6m. Sections 1, 2 and 3 were respectively cut in June (1 cut only), June & August cuts (2 cuts—first cut in June and then the regrowth cut in August) and August cut (1 cut only - delayed cutting till August). Forage DM yields were estimated from each cut. Forage quality of 7-8 top yielding forages for the year was determined. Selenium content for some forages were also analyzed.
Forage Dry Matter Yield
Generally for the grasses, June single cut ( 1st Cut) produced fairly higher mean forage DM yield than June & August double harvest (2nd cut) or August single cuts. Nine out of the 15 grasses tested had higher yields in June single cut than other cutting dates. However, when cut in both June & August (double harvests), Carlton smooth brome grass produced exceptionally higher DM yields compared to other grasses. Except for the perennial ryegrass (BG 34), all grasses produced lower yields when cutting was delayed until August (August only single cut). Overall, perennial ryegrass was the least impressive in terms of early cut, regrowth after cut, winter hardiness and ground cover.
For the legumes, when cut in June, only Algonquin and Spredor 4 alfalfa produced higher than 2500lb/ac. Other legumes produced 930-2400lb/ac. For June and August cuts, AC Caribou produced higher yield (>3500lb/ac) than other legumes. But when cut was delayed to August, yield was generally low and only Algonquin and Spredor 4 alfalfa produced >1000lb/acre. Cutting both in June and August (double cuts) seemed to slightly increase DM yield than either single cut scenarios. Overall, Windsor cicer milkvetch was the least impressive irrespective of when cutting was done.
The crude protein contents of the grasses were mostly in the order of June & August cut (2nd cut) > June single cut > August single cut (Figure 3). A few of the grasses selected for feed tests, did not meet protein requirements of 7-11 % CP for pregnant and post calving beef cows, particularly when cutting was delayed until the August single cut. However, regardless of when cutting was carried out, all legumes tested for quality was well above 11% CP (Figure 4). For both grasses and legumes, the protein contents of the forage were higher with the regrowth from June harvest (2nd cut) than the single June or single August cut.
For the legumes, when cut in June, only Algonquin and Spredor 4 alfalfa produced higher than 2500lb/acre. Other legumes produced 930-2400lb/acre. For June and August cuts, AC Caribou produced higher yield (>3500lb/acre) than other legumes. But when cutting was delayed to August, yield was generally low and only Algonquin and Spredor 4 alfalfa produced >1000lb/acre. Cutting both in June and August (double cuts) seemed to slightly increase DM yield than either June or August only cut. Overall, Windsor cicer milk-vetch was the least impressive irrespective of when cutting was done.
Table 2 shows mineral, detergent fibre and energy contents of selected forages in High Prairie. Except for Pradel tall fescue and Reed canary grass, which met the Ca requirements for beef cows through pregnancy to post calving, all other grasses were short of meeting the Ca requirements. P requirements were also not met by the majority of the grasses. However, all the legumes were satisfactory in meeting both Ca and P requirements regardless of when the forage was cut.
Forage Selenium Content
Selenium (Se) is a very important trace mineral. Reproductive problems, retained placentas, white muscle disease and an inadequate immune system (leading to mastitis and metritis) may result when selenium is deficient in a livestock ration. Selenium is required for catalysing the destruction of toxic oxygen molecules produced during metabolism, thereby protecting the cells from damage and helps with the absorption of fat, including vitamin A and vitamin E, and in proper sperm formation. Deficiency symptoms include unthriftiness and reduced growth. Impaired immune response also occurs, which makes the animals more susceptible to disease.
Despite its importance, selenium analysis is not routinely done on forages due to the high cost ($55/ sample). Because of this, the status of selenium in forages is not well documented. The selenium (Se) requirement of beef cattle is 0.10 mg/kg (0.10 ppm) of diet dry matter. Formulating diets to contain 0.20 mg/ kg (0.20 ppm) is recommended.
We analysed two samples (Carlton smooth bromegrass and Algonquin alfalfa) for Se content from the forage demonstration plots in High Prairie. The results are shown in Table 2. Although sample size was small, this preliminary test is necessary in order to have an idea of what the Se levels could be in some of our forages. Algonquin alfalfa regardless of when cutting was done was consistently lower in Se content than the suggested Se requirements for beef cows. Carlton smooth bromegrass was also lower than the suggested amount but only when cutting was delayed till August (August only cut).
The following grasses were the least affected by winter kill: Crested wheatgrass (Kirk), Timothy (Derby), Reed canary grass (Palaton), Smooth Bromegrass (Carlton), Tall fescue (Pradel Meadow), Hybrid bromegrass (AC Knowles), Creeping red fescue (Boreal) and Tall fescue (Climax). Compared to the grasses, the legumes did well and Anik alfalfa was the least affected by winter kill. Early in the spring, Alsike clover (Aurora) Alfalfa (hybrid force 400) and Matrix alfalfa had earlier better growth and good ground cover than the other legumes. In High Prairie, throughout the year, the two cicer milkvetch varieties were not as impressive as those in Fairview.