Written by: Akim Omokanye,
From: Peace Country Beef & Forage Association 2019 Annual Report
PCBFA’s services to producers include feed testing, analysis and interpretation of results. This report looks at the 2019 feeds (forage type feed and grains) in parts of the Peace Country region. The results are discussed in relation to the nutrient requirements of mature beef cattle.
From July 2019 to January 2020, a total of 179 feed samples from producers across the Peace were analyzed for quality at Central Testing Laboratory (Winnipeg) using standard laboratory procedures for wet chemistry or Near-infrared reflectance (NIR) spectroscopy. For the purpose of this report, the feed types have been grouped into 21 groups as provided by producers (Table 1). We also tested feeds for nitrates.
Only 9 of the feed types submitted for analysis by producers (Alfalfa hay, Alfalfa silage, Barley Grain, Canola plant, Cereal-pea mix Greenfeed, Cereal Silage, Clover hay Oat Grain, Oat pea mix silage) have been able to meet the protein requirements of mature beef cattle at different physiological states (7, 9 & 11% CP). Six of the remaining feeds (Alfalfa Grass, Mix Hay, Cocktail, Grass-clover Hay, Grass hay, Pea Greenfeed, Pea straw - 2019) conveniently met the 9% CP required by a dry gestating beef cow, but not a lactating beef cow that needs 11% CP. Other feed types were either only able to meet the 7% CP needed by a dry gestating beef cow in mid-pregnancy or fell short of the 7% CP suggested for a dry gestating beef cow. Brome aftermath, wheat straw and timothy straw particularly had low CP (below 7% recommended for dry gestating beef cows).
Ca - Twelve (12) feed types exceeded the 0.58% Ca recommended for mature beef cattle (Table 2). Barley grain, Oat grain and Greenfeed 2018 all fell short of meeting the minimum requirements of 0.18% by mature beef cattle.
P - The following feed types had adequate P for mature beef cattle: Barley Grain, Canola plant, Cereal Silage, Clover hay, Cocktail, Pea straw-2018, Oat Grain, Oat pea mix silage, Pea straw - 2019 (Table 2). Most of the other feed types only had sufficient P for a dry gestating beef cow in both mid pregnancy and late-pregnancy.
Mg– In terms of Mg requirements by mature beef cattle, only Alfalfa hay, Alfalfa silage, Canola plant, Cereal Silage, Clover hay and Pea straw-2018 have adequately been able to meet the 0.20% Mg needed by all categories of mature beef cattle. Other feeds (except for Brome aftermath, Timothy straw, Wheat straw, Yellowfeed) only had sufficient Mg for dry gestating beef cows (0.12% Mg). Brome aftermath, Timothy straw, Wheat straw and Yellowfeed all had far below the minimum Mg requirements by mature beef cattle.
K - Except for Barley Grain, Greefeed-2018, Oat Grain and Pea Greenfeed, all feed types sent out by producers have met and in all cases exceeded the 0.7% K recommended for mature beef cattle. Barley Grain, Greefeed-2018, Oat Grain and Pea Greenfeed all fell short of meeting the minimum requirements of 0.6% K by calves (backgrounding and finishing) and dry gestating beef cow .
Na – Of the feed types sent out by producers, only Canola plant, Cereal-pea mix Greenfeed, Oat pea mix silage, Pea/Oat Straw and Pea straw-2018 had adequate Na for mature beef cattle. Greenfeed-2019 only had sufficient Na for growing and finishing calves as well as dry gestating beef cows. Other feeds did not have enough Na for young and mature beef cattle.
Overall, only Canola plant was able to conveniently meet the Ca, P, Mg, K and N recommended for mature beef cattle. Because of the inability of the feeds tested here to meet all the mineral requirements of young and mature beef cattle, it is essential to have free choice minerals (with guaranteed mineral analysis) when feeding any of the feed types tested by producers.
Energy gives the ability to use the building blocks for growth and other productive purposes. Energy can be monitored in the beef cow by watching BCS; low energy rations result in a loss of BCS.
Feedstuff quality analyses and cattle nutrient requirements often use TDN to indicate energy levels. Using %TDN, the Rule of Thumb is 55-60-65. This rule says that for a mature beef cow to maintain her body condition score (BCS) through the winter, the ration must have a TDN energy reading of 55% in mid pregnancy, 60% in late pregnancy and 65% after calving.
Looking at the %TDN of feeds sent out by producers (Figure 1), only Barley grain, Oat grain and Greenfeed-2018 met and even far exceeded the 65% TDN recommended for mature beef cattle. Only 3 of the remaining feed types (Canola plant, Cocktail and Greenfeed-2019) had adequate %TDN for dry gestating beef cows in both mid- pregnancy and late-pregnancy. Other feed-types were either only able to meet the minimum 7% TDN suggested for mature beef cattle (a dry gestating beef cow in mid-pregnancy) or completely fell short of meeting the 7% TDN.
It is important to note that most feed-types sent out by producers this year have come back with very low energy content (total digestible nutrients, %TDN) - mostly below the levels of TDN needed by a dry gestating beef cow. Energy supplements are available in many forms. These include barley grain and oat grain, protein blocks, beef cattle supplements (including liquid supplements).
Beef cattle supplements/feed product labels do not normally report percent TDN or other energy values. The amount of energy provide by the supplement can be quite small. Call the company or local representatives for the actual %TDN in a supplement. Cereal grains (e.g. from barley, oats, mixed grains) can be used in combinations with your laboratory tested feeds using the Alberta Agriculture & Forestry CowBytes Ration Balancing Software. The use of CowBytes is recommended instead of guessing the amount of grain supplementation that may be needed. This will help avoid acidosis problems from feeding grains when trying to increase the energy content of the diet.
Nitrates Test Results
All the Greenfeed (cereals) samples came back with very low nitrates (almost negligible nitrates levels). Both Canola plant and Crested wheatgrass showed high nitrates levels in them. The Canola plant had 1.92% nitrate (%N03) and Crested wheatgrass showed 0.61% N03. Looking at Table 3 below, both Canola plant and Crested wheatgrass would be considered generally unsafe for beef cattle as they have %N03 and this will pose high nitrate problems. They producers were notified immediately about this. Because Greenfeed (cereals) samples had low or negligible %N03 (0.02% N03), the Greenfeed was considered to be generally safe.