It’s time to start planning our winter feeding programs for our cow herds.
This year, there will be a lot of alternative feeds used in Western Canada because of the drought. That means feed testing will become more important than usual. I’ve come up with the five steps to consider when getting feed tested.
Get a representative sample of all feeds that will be fed
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This is a fairly important step and will take time to do correctly. There can be a lot of variation across different areas within a field of forage and it’s important to get a representative sample for each type of feed that might be used in winter rations.
If the forage is baled, most experts suggest sampling at least 20 bales in total, from different parts of the field and not just the bales that are readily accessible. Grabbing samples by hand will not give representative results for feed testing. Producers will need to use a forage probe for bales and will want to obtain cores that are 12 to 15 inches into the bale.
Forage probes are available for purchase at some feed supply stores or can sometimes be borrowed from agriculture extension offices, local forage association offices, nutritionists or veterinarians.
If producers are sampling a silage pit, they may need a longer probe and will want to brush off the outer loose silage and sample from the face of the pit in the four different quadrants, taking five samples per quadrant.
Sampling grazing swaths will involve taking whole plants from multiple swaths in different areas of the field. I like to take a plastic bin out with me to the bales or silage pit when I obtain my core samples and then place each of the core samples in the plastic bin as I sample the bales. I can then thoroughly mix all the samples together and then place a subsample of the mixed feed sample into a zip-lock plastic bag with a label on it to send to lab for testing.
Send samples to a lab for testing
Feed-testing services are widely available across Canada from a number of laboratories. Most will have a forage analysis package available. Although there are many variations, the minimum should include dry matter, crude protein, acid detergent fibre (ADF), neutral detergent fibre (NDF), calcium, phosphorus, potassium and magnesium.
Producers may also want to add nitrate levels to their laboratory request if they are feeding an annual forage that is susceptible to high nitrate levels.
A local livestock extension specialist would be a good person to talk to if there are questions about submitting samples.
If producers are feeding some sort of annual forage or anything out of the ordinary, they should make sure that the laboratory uses a wet chemistry analysis rather than near infrared spectroscopy. NIRS uses wavelengths of light to approximate the nutrient values in a feed stuff, but it becomes much less accurate in feeds that are not analyzed on a regular basis and gives less accurate results on mineral levels than wet chemistry analysis provides. Wet chemistry analysis tends to be more expensive, but the more accurate results are usually worth the slight increase in cost.
Evaluate and plan the ration
Feed testing is useless if producers don’t take the results and do something with them.
They might be able to get help from a local livestock extension specialist, a nutritionist or a veterinarian for this component of the project. There is a simple online feed sample evaluator available at the Beef Cattle Research Council website that will help evaluate a potential ration. Producers are going to have to create multiple winter rations for their herd.
They should have multiple feeding groups in their herd that will have significant variations in nutrient demands:
- Mature cows in good body condition.
- Replacement heifers and first-calf heifers that are still growing and have higher protein and energy requirements.
- Mature cows that are thin or poor condition (sometimes these can be pooled with the heifer group).
Producers will need to plan different rations for each of these groups at different stages of gestation.
These stages are going to depend on calving dates, but the nutritional demands of cows in mid-gestation are very different from cows in late gestation and these requirements increase even more after calving and lactation begins.
In addition, producers will have to take into account environmental conditions and cold temperatures as the weather changes throughout the winter-feeding period when these rations are delivered.
They will probably need a mid-gestation ration, late-gestation ration and a post-calving ration for each of their feeding groups in the herd, but this may vary depending on the timing of the calving season.
Adapt the ‘paper’ ration to real-life feeding instructions
The software programs that we use will often tend to give us the amount of various feedstuffs that an individual cow needs to consume. However, we feed groups of cows not individuals.
Producers will now have to take the ration that was created by a computer program or online calculator and adapt it for real life. This will require some simple math and perhaps some compromises along the way.
They may have to account for feedstuff wastage and or trampling of feed and will need some estimates of weights of bales. Producers may need to figure out what a bucket load of silage weighs or other feedstuff weights.
They will have to translate ounces of mineral per cow per day to bags of mineral per feeding group per week. It will also be necessary to take that computerized ration and convert it into something that everybody can understand in terms of number of bales, bags of mineral or bucket loads of silage.
Monitor and adapt if necessary
Despite all this planning, cows don’t always eat the way we expect them to. There’s an old saying that there are three different rations: one that we design on paper, one that we feed and one that the cows eat.
We need to monitor body condition scores, monitor mineral consumption, and perhaps even evaluate mineral levels at some point by using blood samples or liver biopsies.
Producers may need to adapt their rations if the weather is extremely cold or if the cows are not maintaining body condition as expected.
John Campbell is a professor in the department of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.
