Feed Testing and Ration Balancing
Once feed is harvested and inventory is known, the next step is to determine how to use it most effectively to meet livestock nutrient requirements. Feed testing and ration balancing help producers:
- Stretch feed supplies
- Reduce cost of production
- Prevent nutritional deficiencies
- Maintain cow health, body condition, fertility, and calf performance
1. Sampling: The Foundation of Accurate Feed Testing
Proper sampling is essential to obtain meaningful results.
Sampling Guidelines
- Sample each distinct lot of feed (e.g., hay cut before vs. after rain).
- Core at least 10 bales, chosen randomly.
- For chopped or loose feeds, take multiple grab samples and mix well.
- Contact Manitoba Agriculture or your preferred lab for instructions and sample submission.
2. What the Feed Test Tells You
Key components needed to assess forage quality include:
Dry Matter (DM)
Indicates moisture level and allows fair comparison between feeds.
Crude Protein (CP)
- Includes both true protein and non‑protein nitrogen.
- Calculated from total nitrogen × 6.25.
- Declines with plant maturity.
Acid Detergent Fibre (ADF)
- Includes cellulose, pectin, and lignin.
- Higher ADF = lower digestibility.
Neutral Detergent Fibre (NDF)
- ADF + hemicellulose.
- Indicates bulkiness of feed; higher NDF = lower voluntary intake.
Total Digestible Nutrients (TDN)
Represents energy content.
Estimated using:
TDN% = 88.9 – (0.779 × ADF%)
As forage quality declines, ADF and NDF increase, and TDN decreases.
Estimated using:
TDN% = 88.9 – (0.779 × ADF%)
As forage quality declines, ADF and NDF increase, and TDN decreases.
Minerals
Calcium and phosphorus are essential for:
- Growth
- Lactation
- Reproduction
- Bone health
Example Feed Test Results (DM basis)
Feed Type |
CP (%) |
TDN (%) |
Ca (%) |
P (%) |
Alfalfa‑Grass Hay |
16.20 |
62.56 |
1.48 |
0.20 |
Grass Hay |
12.73 |
58.69 |
0.75 |
0.32 |
Barley Straw |
4.53 |
48.11 |
0.39 |
0.12 |
Wheat Straw |
3.36 |
46.91 |
0.32 |
0.14 |
Barley Greenfeed |
11.03 |
59.22 |
0.48 |
0.16 |
Oat Greenfeed |
13.42 |
61.79 |
0.50 |
0.26 |
Barley Silage |
10.76 |
62.80 |
0.43 |
0.22 |
3. How to Interpret Feed Test Results
As‑Fed vs. Dry Matter
- As-fed: Used only to determine moisture content.
- DM basis: Used for all nutrient comparisons and ration balancing.
Balancing Rations
Use feed test values alongside beef cattle nutrient guidelines to:
- Identify nutrient gaps
- Match feeds to cattle classes
- Determine supplements needed
- Optimize feeding costs
Helpful Tools:
- BCRC Feed Test Evaluation Calculator – assesses if feeds meet cattle requirements.
- FeedPlan Calculator – identifies low‑cost supplement options.
4. Common Questions About Feed Testing
What do DE, NEm, and NEg mean?
These are alternative expressions of energy (digestible or net energy).
For most beef ration formulation, TDN is adequate.
For most beef ration formulation, TDN is adequate.
Are there toxic or deficient mineral levels to watch for?
- Calcium: Toxicity unlikely; negative effects appear above ~4.4%.
- Phosphorus: Upper limit rarely reached in forages.
- Potassium: Should remain below 3%; high potassium may require adjustments to Ca:Mg ratios.
- Magnesium: Rarely excessive in beef rations; typically below concern levels.
Can I formulate my own rations?
Yes. Producers can use several software programs—CowBytes is one of the most commonly used tools for beef cattle ration formulation.
Summary
Feed testing and ration balancing are essential management tools that:
- Improve nutrient use
- Reduce feeding costs
- Support cow health and performance
- Ensure efficient use of feed resources
Knowing what’s in your feed pile allows you to make informed decisions and build rations that meet the needs of your herd throughout the production cycle.