Finishing cattle in hot summer areas requires summer annuals

by Anibal Pordomingo

In most of the United States finishing cattle in summer will be more difficult than finishing cattle in winter.

The difficulties in finishing cattle in the winter and early spring in the USA are due more to the lack of the use of winter annuals than the climate.

The summer is more insidious because the pastures are green and unless we are frequently weighing our cattle we can’t readily see that our gains have fallen to less than a pound per day. Remember, the animal must be gaining 1.7 lbs per day or more in order to fatten.

In hot weather (above 86 degrees F), perennial species drop in quality below that needed for finishing cattle. This is particularly true in areas with rather lengthy summer dry spells such as the Southeast and Pacific Northwest.

The only solution to this problem of poor summer weight gains is to use more digestible summer annuals.

The corn plant grazed green before cob development is the option of first choice in the hotter, summer dry areas for the last two months of summer. Other choices are Sudan and sugar sorghums and soybeans grazed prior to pod set.

GREEN CORN AS PASTURE

The corn plant has the highest potential for summer gains because of its high proportion of soluble carbohydrates, an excellent protein/carbohydrate ratio and highly digestible fiber.

For all intents and purposes, it has no useful regrowth and is a one-pass crop. However, the accumulated amount of forage we can stockpile until we graze it makes this a very economical crop to use.

For best use, it is important to graze the crop intensively with a high stocking density. In areas of Argentina with a climate similar to eastern Oklahoma and Kansas, whole plant corn yields range from 8000 to 15,000 lbs of dry matter per acre at grazing time.

To keep average daily gains high, we should not plan on a use efficiency higher than 50 percent. We want the finishing animal to only eat the leaves of the plant and not be forced to eat the lower digestible stems and stalk.

These residual stems and stalks can be cleaned up later with a follower class. Preferably, mature cows.

At a consumption rate of three percent of bodyweight, a steer initially weighing 750 pounds will eat about 25 lbs of dry matter a day.

If available forage is about 10,000 lbs of dry matter per acre, and we use 5000 lbs a daily stocking rate of 200 steers per acre would be required.

In other words, 200 steers would require an acre of corn per day. One hundred would require a half acre.

These allocations are easily made with a one-wire temporary electric fence. These subdivisions, or slices of the crop, should be made on a daily basis to keep the animals’ diet homogenous. It is best if grazed areas are fenced off after grazing.

One of the limitations of grazing a species such as corn at a right stage is the speed of plant maturation. With grazing we don’t want all the corn maturing at once but prefer that it mature over a 45 to 60 day period.

This will requires a staggered planting time to prevent having to graze too early or too late. We would like to begin grazing the corn when it is shoulder high to the average man.

Actually, grazing corn too early is not the problem of grazing it too late as it only results in a lowered yield. However if you graze it after the start of grain formation, it might cost you your grass fed label.

If you are not producing a labeled product and are only selling a commodity, you can continue to graze the corn as long as the plants are still green. This will give you an additional 15 to 25 days of grazing.

STAGGERED PLANTING

We can spread the corn maturation by stagger planting the corn from early spring to early summer 15 days apart.

These fields will be grazed as separate paddocks using the aforementioned daily strip grazing technique.

This will allow us to distribute the corn grazing season from mid-summer to early fall. Choose the longest season corn varieties you can find. These will usually be those selected for the Deep South.

Many graziers like the older, open-pollinated varieties due to their longer green season, higher leaf digestibility and drought tolerance. With corn grazing we want leafy, late maturing cultivars but grain yield is unimportant.

The corn should be planted with 20 to 40 percent more crop density within the row but at the same width as traditional corn to allow for cultivation if needed. Fertilizer use can be restricted when the crop is to only be used as grazing and no grain fill is desired.

In areas with dry late springs such as the South, a 30 to 45 day period of spring fallow to allow for moisture accumulation before corn planting is best.

GRAZING SOYBEANS

Grazed soybeans are another summer alternative. Soybeans are very efficient water users and require little water prior to pod formation.

As with corn, we want varieties that produce a lot of leaf and are extremely late maturing as we do not want any pod set. A tropical variety would be best if it can be obtained in your area.

Whereas corn is typically grazed in late summer, soybeans are grazed in the early summer.

Combining corn and soybean grazing is an excellent idea as it will help prevent grazing the corn too early before it has reached its maximum grazable biomass.

In contrast to my recommendations of grazing corn hard, soybeans should be grazed lightly as they will regrow.

Again, we only want to remove 50 percent of the leaves at a grazing so that the plant will have sufficient sunlight gathering surface to regrow. The soybeans can then be regrazed in 30 to 40 days.

For planning purposes, we should figure that it will require twice as many acres of soybeans to finish a set of steers as it will with corn due to their lower biomass.

THE SUMMER FORAGE CHAIN

Combining corn and soybeans is a good alternative to perennial pasture to sustain summer weight gains. Here’s a sample summer forage chain.

Coming off of legume/grass perennial pastures in late spring, near-finish weight cattle would enter the soybeans pasture for about a month’s grazing. Once the stagger planted corn is ready to graze we can switch these cattle to the corn on a full-time basis or on half day in each.

The partial day graze will help us to better utilize the soybeans and help stretch the corn crop. However, if the cattle are to be harvested in 20 days or less, it is best to leave them on the corn full-time as the gains will be higher.

A similar partial day graze on alfalfa pasture and corn will improve the summer gains compared to alfalfa alone. This increase in average daily gains is even more dramatic in the fall as compared to alfalfa pasture alone.

It is the use of high quality summer annuals in combination with legume rich perennial pastures and early planed winter annuals that allows for the year around finishing of cattle with no grain.

This is made possible by the use of annual forage species with staggered planting dates and maturities. By using a variety of winter annual species, a field can subsequently be stagger planted with summer annuals for a high quality summer graze.

The dropping of these winter annual paddocks allows you to seasonally increase the stocking rate on your perennials when their growth is the greatest.

Then the summer annuals allow you to decrease your stocking rate on the perennials during the heat of the summer as the finish weight cattle go to the annuals.

Because the summer annuals are grazed off in small acreages, after a short fallow, you can begin your planting of the winter annuals equally early or start a new legume/perennial pasture.

If so desired, a winter wheat crop could be planted on part of the acreage for grain production as well. Because, the cattle redistribute the fertility of the summer crop in their manure, this crop can often be grown without any additional fertilizer input.

Are you seeing the much greater planting flexibility, labor and equipment utilization you have when you have the animal harvest the crop directly? You no longer have to wait for a crop to mature to machine harvest it so your harvest window is incredibly long.

Also, we are no longer interested in maximizing grain yield, which requires high levels of nitrogen or pod fill, which requires plentiful water.

WHAT KIND OF GAINS CAN WE EXPECT?

Weight gains will depend upon the animal’s size, breed, biotype and category, and on the plant nutrition, health and maturity stage; but, under normal circumstances a green corn pasture could produce gains of 2.0 to 2.8 lbs per day.

Soybeans would have a lower potential of 1.8 to 2.2 lbs per day.

The more mature we let the annuals get the lower the average daily gain will be. The one exception to this is corn, which will have a very steady quality up until grain formation. I know the Argentine forage chain sounds complicated but it is really simple once you think it through. However, it does require that you sit down and think it through.

The big problem is that you can be successful in cow-calf or stocker cattle with a far lower forage quality than you can with finishing cattle and many of you have not had much experience with planting and grazing annuals. This will come with time.

Argentina and much of the USA lie at the same latitude and have similar rainfalls. Whatever we can do, you can do and vice versa. This is why we can both learn from each other.

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