In October, a West Texas hay stack can seem better than it actually is. The barn looks full, round bales are lined up, and there’s still grass in the pasture. From the truck, it might seem like winter feed is already taken care of.But when the first strong cold front hits, cows eat through hay faster than you expect, manure gets firmer, calves don’t look as healthy, and feed costs go up. The issue isn’t always not having enough forage. Sometimes there’s plenty, but it doesn’t have enough usable protein or energy.
That’s why October is a good time to test both hay and standing forage. Warm-season grasses are finishing up, most hay is already baled, and ranchers are starting to look at winter supplement prices.
A simple forage test lets you buy feed to fix a real shortage, not just pick something with a flashy label. It also helps you figure out which hay to give to dry cows, young females, lactating cows, or newly weaned calves.
Testing alone won’t create your whole feeding plan. Cow size, body condition, production stage, weather, how much they eat, and how you deliver feed all still matter. But a good forage test gives you a solid place to start. Without it, you’re just guessing about your winter ration.
Why October Forage Testing Pays
October falls between the end of the growing season and the expensive stretch of winter feeding. That gives producers time to answer several useful questions:
- Is the hay adequate for mature, dry cows?
- Should you reserve better hay for first-calf heifers or lactating cows?
- Does the herd need protein, energy, or both?
- Could any hay lots contain excessive nitrate?
- How much supplement should you purchase?
- How long will the available forage realistically last?
Testing might show that one batch of hay is much better than another. Instead of feeding bales at random, you can give the best hay to the cattle that need it most.
It can also keep you from buying the wrong supplement. If your hay has enough protein but not enough energy, a high-protein product won’t fix the real problem. If mature grass is low in protein, cattle may have trouble digesting it and eating enough, even if there’s still plenty of dry matter in the pasture.
The goal isn’t just to find the cheapest feed. It’s to buy the nutrients your cattle actually need at the lowest practical delivered cost.
This difference matters, especially since every feed dealer offers a different tub, cube, or liquid product that claims to get cows through the winter.
Start With a Representative Hay Sample
First, divide the hay into separate lots. A lot should contain hay that is reasonably similar in:
- Forage species
- Field of origin
- Cutting date
- Stage of maturity
- Fertility history
- Rain exposure
- Storage method
Don’t mix early-cut irrigated bermudagrass, late-cut native grass, and bought sorghum hay into one sample. The average you get won’t really describe any of them.
Use a forage probe if you can. For large round bales, take samples from the curved side toward the center. Sample at least 10 bales from each lot and mix the cores in a clean bucket. Don’t just pick the best-looking or easiest bales to reach.
For small square bales, collect cores through the ends of at least 20 bales. Mix the cores from each lot and submit the amount the laboratory requests.
Label every sample with the hay type, cutting, storage location, and intended cattle group. Three months from now, “Sample 2” will not tell you much.
Which Laboratory Tests Should You Request?
A basic forage test should give you enough info to start planning your winter feeding. At the very least, ask for dry matter or moisture, crude protein, and an energy estimate like total digestible nutrients (TDN).
Dry matter and moisture
Dry matter means everything in the feed except water. Always compare cattle needs and forage nutrients using dry-matter values.
If hay is 88 percent dry matter, 25 pounds fed as-is contains:
25 pounds × 0.88 = 22 pounds of dry matter
Moisture affects how well hay stores and how much nutrition you’re actually buying. A ton of wetter hay has fewer pounds of real dry feed.
Crude protein
Crude protein helps rumen microbes, digestion, intake, maintenance, milk production, and growth. Mature forage that’s low in protein may not be used well by cattle.
A dry, mature cow in good shape usually needs less protein than a lactating cow, a growing heifer, or a newly weaned calf.
Total digestible nutrients
TDN tells you how much energy is in the feed. Thin cows, young females, growing calves, and lactating cows usually need more energy than mature, dry cows.
Always compare numbers using the same basis. Don’t compare a dry-matter value from a forage test with an as-fed value from a supplement tag.
Nitrate and Prussic Acid Are Not the Same Risk
cloudy weather, low temperatures, and disrupted plant growth can increase concern.Request a nitrate test when those conditions apply. Nitrate analysis is not always included in a standard forage panel.
Watch the reporting units closely. Labs might report nitrate as nitrate ion, nitrate-nitrogen, or potassium nitrate, and those numbers aren’t the same. Ask the lab, an Extension specialist, a nutritionist, or your vet to help you understand the results.
Producers also need to tell nitrate risk apart from prussic acid risk. Both can be issues in sorghum-family plants, but they’re different problems.
Nitrate can stay in harvested hay. Prussic acid is usually found in young growth, drought-stressed plants, and frost-damaged sorghums or johnsongrass. Prussic acid may go down as hay cures, but nitrate doesn’t go away with normal curing.
Never put hungry cattle straight onto questionable forage. Talk to a vet or nutritionist before you dilute or feed forage with high nitrate levels.
Match the Report to the Cattle
A forage report doesn’t mean much until you compare it to what a specific group of cattle needs.
A 1,300-pound mature cow in the middle third of pregnancy does not have the same requirements as a lactating fall-calving cow. A first-calf heifer must support maintenance, pregnancy or lactation, and her own continued growth. Thin cows also need additional energy if you expect them to regain condition.
That last factor, expected intake, is easy to overlook. Cattle require a certain amount of protein and energy each day. The percentage needed in the diet depends on how much dry matter they consume.
For example, a cow needing 1.7 pounds of crude protein would require a higher dietary protein percentage if she consumed 20 pounds of dry matter than if she consumed 25 pounds.
That’s why a percentage on a report can’t balance the ration by itself. You need to connect the nutrient level with how much the cow will eat and what she needs each day.
A Sample Winter Feed Calculation
Let’s look at a group of 1,300-pound, spring-calving cows in good shape and in the middle third of pregnancy. Their needs will go up as they get closer to calving, so these numbers are just examples to show how the calculation works.
Assume each cow consumes 25 pounds of hay as-fed. The hay tests 88 percent dry matter, 6 percent crude protein, and 52 percent TDN on a dry-matter basis.
The hay supplies 22 pounds of dry matter:
25 × 0.88 = 22 pounds
Protein supplied is:
22 × 0.06 = 1.32 pounds
TDN supplied is:
22 × 0.52 = 11.44 pounds
Now consider a supplement containing 20 percent crude protein and 75 percent TDN on a dry-matter basis. Supplying the 0.44-pound protein deficit would require:
0.44 ÷ 0.20 = 2.2 pounds of supplement dry matter
At 90 percent dry matter, that equals about 2.45 pounds as-fed. It would also provide approximately 1.65 pounds of TDN.
What That Calculation Does and Does Not Prove
This example shows how much supplement would cover the estimated daily protein shortage. It doesn’t prove that 2.45 pounds of supplement will make an 8 percent crude-protein diet.
If the cow eats all 22 pounds of hay dry matter plus 2.2 pounds of supplement dry matter, total intake becomes 24.2 pounds. The ration would contain 1.76 pounds of crude protein, or about 7.3 percent of total dry matter.
That doesn’t automatically mean the feeding rate is wrong. The example started with a daily need of 1.76 pounds of protein, not a rule that the ration must have exactly 8 percent protein.
Real results can vary because supplements can change how much hay cattle eat and how well they digest it. Some supplements help cattle use low-quality forage better, while others just replace some of the hay they’d eat. Weather, body condition, competition, and how appealing the forage is also affect intake.
Use this calculation as a first check. It tells you if a product can cover the estimated nutrient gap and gives you a starting point for feeding. A nutritionist can fine-tune the ration if cattle have high needs, the forage is poor, nitrate is present, or you’re mixing several feeds.
The key step is to calculate pounds of nutrients supplied instead of choosing a supplement based on crude-protein percentage alone.
Practical Management Strategies
When you get the results, sort both the forage and the cattle. This usually saves more money than feeding the same ration to the whole herd.
Reserve higher-quality hay for:
- First-calf heifers
- Thin cows
- Lactating fall-calving cows
- Growing replacement heifers
- Recently weaned calves
Lower-quality hay can work for mature, dry cows in good shape if it still lets them eat enough and meets their needs.
How you deliver feed matters too. A product meant for daily feeding might not work if you can only feed twice a week. Self-fed products save labor but need intake monitoring. Hand-fed cubes give you more control but add fuel, equipment, and labor costs.
Add supplements slowly. Make sure there’s enough space for timid and young cattle, and measure how much they actually eat. If a group of 30 cows should eat 90 pounds a day but usually eats 130, the label’s expected intake isn’t matching what’s happening on your ranch.
Keep each forage report together with the supplement record for the cattle that got it.
Test First, Then Spend
Winter feed costs too much to buy out of habit. Before you order more cubes, tubs, or hay, check what you already have on the ranch.
A good October forage test can show if you’re short on protein or energy, spot possible nitrate risk, and help you save better hay for cattle that need it most. It can also keep you from overfeeding an expensive nutrient the herd already gets enough of.
Take samples from each main hay lot. Clip the pastures your cattle will graze. Ask for the right tests, compare all feeds on a dry-matter basis, and figure out the nutrient gap before you buy anything.
Then match your feeding plan to cow size, body condition, production stage, expected intake, weather, and how you deliver feed. Watch your cattle and make changes if their condition or how much they eat shows the plan isn’t working anymore.
Go to the feed store second. Check your hay stack first.
