Incorrect feed analysis can cost you money and hurt milk production. The problem is often not the lab, but the sample itself. Let's fix that with proper sampling.
Properly sampling forage involves collecting multiple small subsamples from various locations, combining them into one composite sample, and then using a method like quartering to create a final, representative sample of about 400g to send to the lab.
Getting accurate data from a lab is crucial. I've seen farms waste a lot of money and lose production because their feed rations were based on bad numbers. A test result is only as good as the sample you send. If the sample doesn't represent the entire pile of silage or bunk of TMR, the diet you formulate could be completely wrong. It's a simple step, but doing it right makes all the difference. Let's dive into the correct procedures for the most common feeds on your farm.
How Should You Sample Corn Silage for Accurate Testing?
Grabbing a single handful from the silage face won't work. This lazy sampling leads to wrong diet formulations and poor herd performance. You need a systematic approach.
Use a silage sampler to take cores from nine points across the silage face, staying 30-50 cm from the edges. Mix these cores thoroughly, use the quartering method1 to get a 400g final sample, seal it, and ship with ice packs.
A silage pile is not uniform. The density, moisture, and level of fermentation can vary from top to bottom and side to side. That's why a single grab sample is so misleading. To get a truly representative sample, you need to follow a strict protocol. I recommend one of two methods, depending on the safety of your silage face.
Method 1: Direct Face Sampling (The Grid Method)
This is the gold standard for bunkers, piles, and wrapped bales.
- Get Your Tools: You'll need a silage sampler, a clean plastic bucket, a large plastic sheet, sample bags, and a marker.
- Sample Collection: Imagine a tic-tac-toe grid on the silage face. Take a sample from the center of each of the nine squares. It's important to stay about 30-50 cm away from the top, bottom, and sides, as these areas can be affected by weather and might not represent the bulk of the feed.
- Mixing and Quartering: Put all nine samples into your clean bucket and mix them together thoroughly. Then, pour the entire mix onto the plastic sheet and flatten it into a square. Divide the square into four equal quadrants. Discard two opposite quadrants. Combine the two remaining quadrants and repeat the process until you have about 400 grams left. This is your final sample.
- Bagging and Shipping: Immediately place the sample in a bag, squeeze out as much air as possible, and seal it. Label it clearly. For best results, ship it in a foam box with an ice pack.
Method 2: The Safety-First Approach
For very high or potentially unstable silage faces, safety comes first.
- Create a Pile: Use a loader or defacer to take a fresh cut from the silage face and place it in a pile on clean ground.
- Collect Subsamples: From this new pile, take 6 to 10 large handfuls from different spots—high, low, left, right, and center.
- Mix and Quarter: From here, the process is the same as Method 1. Mix all the handfuls in your bucket, and use the quartering method1 on your plastic sheet to get your final 400g sample.
What's the Correct Way to Sample a Total Mixed Ration (TMR)?
Your TMR looks perfect in the wagon, but the cows aren't performing. The mix might be inconsistent or sorted in the bunk. A poor sample won't show you this.
To sample TMR, take 12-20 handfuls from different spots along the entire feed bunk right after delivery. Combine them, mix well, and use the quartering method1 to get a final 400g sample. Seal it immediately and send for analysis.
The timing of your TMR sample is everything. You must take the sample right after the feed wagon delivers it to the bunk, but before the cows get to it. This gives you a true picture of the ration you formulated and delivered. If you wait until after the cows have eaten, your sample will only represent the leftovers they refused to eat, which is useless data. The goal is to check the ration you made, not what the cows sorted through.
Here is the step-by-step process I use on farms:
- Walk the Bunk: Start at one end of the feed bunk and walk to the other. As you go, take 12 to 20 handfuls of the TMR. Don't just skim from the top. Grab from the top, the middle, and near the bottom of the pile. This is critical because smaller particles can settle, and a top-grab won't be accurate.
- Create a Composite Sample: Place all these handfuls into a single clean plastic bucket. Use your hands to mix it all together thoroughly. You are trying to create one small pile that perfectly represents the entire length of the feed bunk.
- Quarter It Down: Just like with silage, pour the mixed TMR onto a clean plastic sheet and use the quartering method1. Divide, discard opposite corners, and remix until you're left with about 400g.
- Bag and Label: Put your final sample into a sealable bag. Squeeze the air out, seal it tightly, and label it with the date, time, and ration name. If you can't ship it right away, freeze it to prevent it from fermenting. Some farms with a drying oven will do an on-farm dry matter test2 first, which is great for immediate feedback, but you should still send the sample to the lab for a full nutrient profile.
How Do You Properly Sample Hay Bales for Analysis?
Judging a bale of hay by its color is a gamble. A sun-bleached exterior can hide high-quality hay inside, or a nice green exterior can hide mold. A hay probe is the only way to know the truth.
Use a hay probe to take core samples from the center of 8 to 10 random bales from the same lot. Combine all the cores into a single sample bag. The final composite sample should weigh around 200-300g. Seal and label it for the lab.
I can't stress this enough: you cannot get a representative sample by just grabbing a flake of hay. The outer layers of a bale are always different from the core due to weather exposure. A hay probe is a simple tool, often attached to a power drill, that cuts a core through the bale, giving you a cross-section of all the layers inside. This is the only way to get an accurate picture of the hay's nutritional value.
| Here's the right way to do it: | Step | Action | Why It's Important |
|---|---|---|---|
| 1. Gather Tools | You need a hay probe, a power drill (if needed), and a large sample bag. | Having the right tools makes the job fast and accurate. | |
| 2. Select Bales | Randomly choose 8 to 10 bales from the same "lot" (e.g., the same field and cutting). | Don't just pick the easy ones. A random sample prevents bias and represents the whole lot, not just the best or worst bales. | |
| 3. Probe Correctly | For square bales, probe from the center of the short end. For round bales, probe from the side, toward the center. | This ensures your probe cuts through the maximum number of layers or flakes, giving you a much more representative sample. | |
| 4. Combine Cores | Empty the core from the probe into your sample bag after each bale. All 8-10 cores go into the same bag. | This creates a single composite sample. Do not send individual cores. The lab needs one sample that represents the entire lot. | |
| 5. Finalize Sample | You should end up with about 200-300g of material. Gently mix the cores in the bag, squeeze out the air, and seal it. | Label the bag clearly with the lot information and send it to the lab. |
Conclusion
Proper sampling isn't hard, but it demands consistency. Correct and disciplined sampling provides reliable data, leading to better rations, healthier cows, and a more profitable farm.
Pro-Tip: Always try to ship your samples on a Monday or Tuesday. This prevents the package from sitting in a warm warehouse over the weekend, which can cause the sample to ferment and spoil, ruining the test results.
