Utilize Crop Aftermath Grazing To Supplement Nutrition At Key Gestational Times

By: Kris Ringwall, Beef Specialist NDSU Extension Service

Fall is the time to take advantage of the gift of crop aftermath grazing. Why a gift? Well, generally, all you need to do is open a few gates and let cows gain weight grazing crop aftermath.

If the bull was turned out June 1, the second trimester of the cows’ pregnancy starts early to mid-September and the third trimester starts Dec. 12. Thus, the last week in September starts a positive opportunity to position the cows for calving and rebreeding next year.

Plus, now is the time to evaluate the plans for winter. Feed inventory, cattle inventory, pasture usage and prepping calves for weaning are all on the table. September started a window of nutritional change for cow herds that had an early June bull turnout.

Nice fall weather, much like we currently enjoy, tends to downplay the nutritional needs, but let’s not forget them because more than 70 percent of the costs of a typical cow will be in feed.

Weight gain is difficult for a cow once she enters the last third of gestation, when the ever-growing calf and cold winter nights take a toll. We want the cows to be in good condition at calving next spring and even better condition at breeding next summer.

So when do we put weight on the cow? Well, the middle three months of gestation, or pregnancy, would work. Cow milk production is decreasing, weather is favorable and fall feedstuffs generally are readily available. Crop aftermath is bountiful across the country.

When I drive by fields that are not fenced nor have access to water, I always ponder about how much a cow would enjoy that field. For example, a moderately milking 1,300-pound cow would like to eat her fill of good, green grass prior to weaning. In reality, she will try to eat all that she can to milk.

After weaning, that same cow keeps eating if feed is available. When a cow eats above her requirements, she gains weight. In this case, replacing the weight she lost raising her calf, along with adding more body condition (commonly called fat) in preparation for winter, is the hoped-for scenario.

Because the third trimester of the cow’s current pregnancy has not been reached, milk production ceases at weaning, and good weather provides the opportunity to utilize cheaper feed resources. Essentially, the cow will eat in excess of her requirements in the crop aftermath buffet.

A good management option is to sort the thinner cows and send the best to fall pastures. These pastures will put the needed feed in front of the thinner cows, and the cows will improve their body condition score.

In the meantime, the moderate- to heavier-conditioned cows can be grazing areas that are less lush. However, most ranchers will let all their cows enjoy fall aftermath grazing, keeping life simple. All the cows should respond with increased conditioning and be better prepared for winter and next year’s calving.

Also keep in mind this very generic approach to ration balancing: If you do not have some mix of green and yellow in the ration or daily feed intake while grazing, more than likely the ration is unbalanced. Take a look. More green is not the problem, but more yellow and brown means this is the time to involve your local nutritionist to develop a proper supplement.

Because not all producers turn their bulls out on June 1, let’s review the dates of the second trimester for some common bull turnout dates:

* If the bull went out May 1, early August starts the second trimester and Nov. 9 starts the last third of gestation.

* If the bull went out July 1, early October starts the second trimester and Jan. 11 starts the last third of gestation.

* If the bull went out Aug. 1, early November starts the second trimester and Feb. 12 starts the last third of gestation.

* If the bull went out Sept. 1, early December starts the second trimester and March 12 starts the last third of gestation.

These dates are critical to managing the cow herd’s nutrition and controlling costs. Visit with your local nutritionist and put together a balanced nutrition program to give your cows the best opportunity for a trouble-free calving season next year and a breeding program that puts 70-plus percent of your calves in the first 21 days of breeding.

Yes, fall grazing can be the gift that can make a real difference in the productivity level of the herd. The challenge for many producers is the business of getting ready for winter. The fall weeks slip by, and all of sudden the third trimester is here and we still are catching up.

Granted, the opportunity may not be available for everyone, but if it is in reach, reach out and see what you can do. The cows will enjoy it and the benefit is worth it.