Cover Crop Grazing Guide

Spring is around the corner, and for most of our trade area that means cows are coming off fall and winter pasture. Hay or silage is usually the go-to to keep cows in good condition, but another option many of our customers are using is cover crops.

Cover crops have been gaining popularity across the state for several reasons: increased organic matter, weed suppression, and the feed value they provide when grazed or harvested. Many producers seed cover crops after silage or soybeans, planting rye, wheat, or even oats. If they were planted early enough or we had a mild winter, it is not uncommon to see 8 to 12 inches of forage by this time of year.

Grazing that forage can be a cost-effective way to stretch feed supplies and reduce the amount of hay being hauled over the next few months.

Putting a Number to Your Forage

One of the most common questions is: How much forage is really out there, and what is the best way to graze it?

On our ranch, we use temporary fence and move a wire to give cows just a few acres at a time. This allows them to graze the forage down evenly instead of trampling and wasting it.

To estimate available forage, we:

Measure the height of the cover crop in several spots and take an average.

Multiply the average height (in inches) by 200 pounds, which is a common estimate of dry matter per inch per acre.

Multiply by the percentage we plan to utilize. In our case, we aim to use about two-thirds and leave one-third behind.

Example:
12 inches tall × 200 lbs × 0.66 = 1,584 lbs per acre available

Next, we calculate daily intake:

1,400 lb cow × 3% body weight × 15 head = 630 lbs per day
In this scenario, one acre would provide about 2.5 days of grazing for 15 cows.

That simple math gives you a clear picture of how long your acres will last and helps prevent overgrazing.

Do Cows Need Anything Else?

Another frequent question is: If cows are on cover crops, do they still need supplemental feed?

While cover crops provide excellent nutrition, the ration still needs to stay balanced. We recommend keeping a quality mineral, such as SFG Cow-Calf 6 ADE, in front of the herd at all times.

If the cover crop is growing rapidly and is lush or “washy,” a protein tub may also be needed. Washy forage can be a challenge, especially in cold weather, because it is high in moisture and lower in effective fiber.

Regardless of the cover crop, it is important to keep a bale of dry hay available. Some producers use cornstalks or oat hay. The added dry matter supports rumen health and helps cows maintain body condition, especially if temperatures turn colder.

Measure What Matters

You cannot manage what you do not measure. If you would like help taking feed samples, running feed calculations, or choosing products to get the most out of every acre, contact me at (641) 218-4015 or reach out to any SFG location. We would be glad to help you make the most of your forage this spring.