Why test my feed?
Next to ensuring you have feed, the most important part of developing a winter feeding strategy is feed testing, for a few reasons:
1) Feed quality (the energy and nutritive value of feed) varies from year to year, and even from field to field. It depends on many factors such as growing conditions, plant variety, maturity at harvest, harvest conditions, and storage conditions.
- Mature plants are higher in NDF, which limits intake, without contributing to nutrition
- Nutrient quality and availability can be depleted quickly under poor harvest conditions
- Nitrates can accumulate in cereals harvested after a frost
- Mineral depletion or accumulation occurs in plants depending on soil characteristics
- Ergot and other mycotoxins are more likely in wet years
- Improper ensiling can increase risk for toxins (botulism), and reduce nutritive content of silages
2) Knowing specific nutritive values of feedstuffs allows a tailored nutrition program to be developed using least cost formulation. This ensures that cattle are receiving the recommended level of TDN and protein, potentially preventing over-supplementation. This is particularly important to consider during pregnancy, as it can impact cow condition, fetal development, and colostrum production.
3) It is important to pair feed testing with water testing. As poor water quality can upset a good nutrition program by providing excess nutrients, or binding important nutrients, like copper, to make them unavailable. The Saskatchewan Ministry of Agriculture in the EI Wood Building offers agricultural water testing free of charge.
How do I test my feed?
The value of feed testing is only as good as the sample taken, so it is important to take representative samples from each feed source/lot.
A “lot” is considered forage from the same field, cutting, and stage of maturity. Not exceeding 200 tons dry matter.
Round Bales: A core sample is better than a grab sample. SWAHC has a core sampler available to lend. Core samplers can also be borrowed from the Sask Ministry of Agriculture Regional Office.
- sample from the side of the bale at the point of the largest diameter
- sample 15-20 random bales per lot of forage
- take a sample at a right angle to the curvature of the bale, parallel to the ground
- entire sampler tube must be inserted into the bale
- forages from the same lot can be combined into one bag
- large sealable bags work nicely with the air squished out
- hay samples should be dry
Square bales: Same procedure as round bales, except samples taken from the end of the bale.
Swath grazing: Again, it is important to get a representative sample of the field. Multiple grab samples from across the field will be needed. It is recommended to test swaths in October, and again in March if cattle will be swath grazing in the spring.
Silage pits: Multiple grab samples must be taken from across a fresh bunker face. 12-15 sites (or 1-2 lbs). Avoid moldy or spoiled samples. These can be combined into one labelled sample bag, with the air squeezed out of the bag. Silage samples should be placed in the freezer to prevent spoilage if not being submitted immediately.
Labeling samples for submission: Please label in permanent marker directly on the bag.
SWAHC would be happy to submit feed samples for you.
You can also submit samples yourself. Information and pricing available at:
Further resources available online:
Written by: Dr. Brittany Wiese