Trial Site: Fairview Research Farm
Research Coordinator: Dr. Akim Omokanye
From: Peace Country Beef & Forage Association 2016 Annual Report
Oat is the most popular cool-season cereal crop grown for forage and has become a reliable source of conserved forage for over-wintering beef cattle in the Peace Country region. In an effort to continue to identify oat varieties that have superior forage production for the region, PCBFA tested several oat varieties in Fairview in 2016. The test was part of the Regional Silage Variety Trials (RSVTs) testing program, which includes testing of new oat varieties as they become available for adaption, forage yield and quality across Alberta. In addition to the findings presented here from our trial, the results from the RSVTs across the different trial sites in the province will also be reported in the Alberta Seed Guide (www.seed.ab.ca).
Methods
Site: The study site was at the Fairview Research Farm (NW5-82-3W6) on RR #35, MD of Fairview. The site had soybeans in 2015. Soil test at 0-6” soil depth done at Exova laboratory (Edmonton) prior to seeding showed an organic matter content of 7.3%, a pH of 5.4 (acidic) and an electrical conductivity of 0.58 dS/m. The field was cultivated before seeding.
Randomized complete block design in 4 replications was used in small plots measuring 11.04 m2 (118.8 ft2).
Treatments (Varieties): A total of 10 oat varieties was tested in 2016.
1. AC Juniper – general purpose oat, early maturing
2. AC Morgan –milling or feed oat, but commonly used for silage or green feed, late maturing
3. AC Mustang – feed oat
4. CDC Baler – forage oat
5. CDC Haymaker - forage oat
6. CDC Seabiscuit - milling oat
7. CDC SO-1—(Super Oat number 1) – Feed/forage oat
8. Derby– general purpose, late maturing
9. Murphy– forage oat
10. Waldern – feed oat
CDC Haymaker is a forage oat variety that offers a high forage yield advantage in the field versus normal grain varieties. Haymaker produces huge leaves and thick stems to deliver impressive forage tonnage. Growers have been finding success with CDC Haymaker in greenfeed, silage, and swath grazing applications both grown alone or in a forage blend.
Seeding rate and date: A rate of 300 plants/m2 (27.8 plants/ft2) was used. A 6-row Fabro plot drill at 9” row spacing was used to seed. Seeding was done on May 16.
Fertility according to soil tests (actual lbs/acre): 0 N + 33 P + 47 K + 0 S (broadcast). Soil test showed adequate amounts of N & S for the crop, so N & S were not applied.
Spraying: Roundup WeatherMAX® was used as pre-emergent 7 days after seeding. In-crop spraying was done with 2, 4 - D 700 at 0.35 L/acre. Rouging was done a few times.
Measurements taken at milk stage:
Prior to harvest, stand assessment for stand uniformity was done.
Random plants were selected for plant height (up to flag leaf only) measurement at milk stage.
Forage yield & quality determination: at soft dough stage, plants in the 4 centre rows 10 feet long were harvested, weighed fresh, sub-sampled (about 500 grams), air dried for some days and then weighed to determine dry matter (DM) content. Forage samples were analyzed for quality using standard procedures for wet chemistry at A & L Laboratory, Toronto.
Results & Interpretation
Plant Height & Lodging
Varieties showed significant differences in plant height (Table 1). Plant height was highest for Waldern (85.9 cm).
No lodging was observed for any of the varieties tested in 2016.
Forage DM yield
The forage DM yield varied from 3.12 tons/acre for AC Juniper to 4.44 tons/acre for CDC Haymaker (Figure 1). CDC Haymaker oat had significantly higher forage DM yield than both Murphy and AC Juniper oat varieties. Of the 9 varieties compared to check (CDC Baler), only one (CDC Haymaker) had higher yield advantage with 109% of check. Other varieties appeared to have 77 to 99% DM of check.
Forage Quality
Crude Protein (CP) - The forage CP content did not significantly differ among varieties tested. The protein varied from 11.7% for Waldern variety to 13.8% for CDC SO-I oat, indicating that CP was generally above 11% (Figure 2). Only CDC SO-I, AC Mustang and CDC Seabiscuit had >13% CP.
The CP content obtained in this test therefore shows that the oat varieties tested here at the milk stage all met the protein requirement of a mature beef cow, which is 7% at second trimester, 9% at third trimester and 11% after calving (during lactation). In terms of the protein requirement of growing and finishing calves, varieties were well within the recommended 12-13% protein.
Total Digestible Nutrients (TDN) - The forage TDN differed significantly among varieties tested. Except for CDC Baler, CDC SO-I had significantly higher TDN than other varieties tested (Figure 3). The forage TDN varied from 61% for Waldern to 65% for CDC SO-I oat.
The TDN values show that all varieties had enough TDN for a dry gestating cow, which requires 55% TDN at second trimester and 60% TDN at third trimester. But for a lactating beef cow, only CDC SO-I oats met the 65% TDN needed.
Minerals - The forage macro– and trace-minerals are shown in Table 2. For a dry gestating cow, all varieties have sufficient minerals (except for Cu). But for a lactating cow, Ca and P were inadequate in meeting the requirements of this category of cow. The forage Cu content from all varieties tested was far less than 10 ug/g needed by calves and mature beef cattle.
According to Alberta Agriculture & Forestry publication “Trace Minerals for Beef Cows”, more than 90 percent of the feed produced in Alberta is low in copper. Cases of copper deficiency are common. Symptoms of deficiency include anaemia, impaired reproduction in cows, bleaching of the hair coat, scours, unthriftiness, stunted growth and sudden death. A greater incidence of internal and external parasites has been noted in copper deficient animals. There is also an increased tendency for bones to fracture in calves and an increased incidence of lameness. Mineral mixes containing Ca and/or P would be good sources of supplementary trace elements if the levels of trace elements in the mix fell in the middle to upper end of the following recommended range for Cu: 2,000-3,000 mg/kg. Such minerals could be fed with red or blue salt.
Detergent Fibers (ADF & NDF) and non-fiber carbohydrates (NFC)
Both detergent fibers (ADF & NDF) as well as NFC are shown in Table 3. The forage fiber content (measured by ADF or NDF) in particular is a strong predictor of forage quality, since it is the poorly digested portion of the cell wall. The ADF values are important because they relate to the ability of an animal to digest the forage. As ADF increases, digestibility of forage usually decreases. The NDF values are important in ration formulation because they reflect the amount of forage the animal can consume. As NDF percentage increases, forage DM intake will generally decrease.
Generally, NFC is more rapidly digested than fibers. It is a significant source of energy for the rumen microbes. The microbes also use NFC to make microbial protein. Looking at Table 3, of the 10 oat varieties tested, CDC SO-I had the lowest ADF & NDF, higher NFC and highest values for other forms of energy as well as RFV. This therefore confirms the better quality of CDC SO-I as previously reported in PCBFA studies. Because of the high NFC value for CDC SO-I, this variety will provide more energy and microbial protein sources in the rumen than other varieties (except for AC Juniper which had higher NFC value than CDC SO-I).
