However, it is also the most critical time for spring-calving females, and skimping during this time in feed will not pay out in the long run.
Pregnant cows ramping up to calve have nutritional needs that are going to steadily increase in this third trimester and peak in the first two months after calving, when milk production is the highest. The better shape she can be when she calves, the more likely she is to breed back and return our investment in her.
Remember, it takes approximately six years for a home-raised heifer to start paying us back in profit, and that is with a calf by her side every year, so it is important that we maintain the breeding female’s nutrition and set her up for success to conceive and calve every year.
Watching the thermometer
Research has shown that at a body condition score (BCS) of 5, adult cows have the maximum chance at conception. The adult cow at a BCS 5 will have a nice sleek covering over her ribs with the last two ribs toward her rear, the 12th and 13th, lightly covered as well. The area on either side of her tailhead will be smoothly filled as well, with no capping or fat stacking.
If she is heavier than this, conception may not be optimal, plus we will have wasted feed. Less condition than this, and we can expect a reduced conception rate. As the adult breeding female is going to use the highest amount of energy after calving, we like to ensure she is in a BCS of 5 at calving.
Winter is a time when the cow is using a lot of energy. Here in the northern Great Plains, cattle have to contend with both cold and wind. Wind chill can be in the -50ºF range on some days, so the animal is burning a large amount of calories to maintain herself.
If she is out on the range and has to walk to water, or is grazing in the open, she is burning even more calories. Windbreaks and shelterbelts do reduce wind chill, but they are not always dispersed evenly in a pasture.
Depending on the severity of the winters, consider the fact that for every degree Fahrenheit below the “lower critical temperature” threshold, beef cattle require 1 percent more energy in the diet, as their maintenance energy needs increase and they will naturally start increasing feed intake to meet those needs.
This critical temperature can vary from 59ºF if the hair coat is soaking wet to 18ºF if the animal has her heavy winter coat and if conditions are calm and dry. Her fat condition, which is estimated by BCS, will also make a difference as fat has insulative value as well as being stored energy.
An assessment of our cows at the beginning of her third trimester, three months before she calves, can help us decide type and amount of added feed. Thin, young and timid cows may need to be sorted and fed a higher-quality diet if they have not handled the winter well.
In addition, if weather conditions are forecast to be severe, our feed quality and amount will need to be upgraded.
High energy inputs
One of the wonderful aspects of the rumen is: It is a huge fermentation vat, so it internally heats the cow if it is kept well stoked with the right type of fuel. Making sure our forages and supplemental feeds meet those standards is important.
Testing our forage feeds is a cheap insurance policy at $15 to $25 a sample and allows us to accurately determine protein and energy values, as variability can be very high in forages.
Co-products from the grain industry, such as distillers grains, tend to be much more consistent in nutrient content, but it is wise to check on fat content and overall feed quality tests from your feed source.
Overfeeding to play catch-up if you need to upgrade cow condition will not be cost-effective. If the feed program needs to be amped up, work with your extension agent or nutritionist to figure out the most cost-effective way of reaching your animal performance goal.
Most often, in late winter, we will need to begin feeding higher-quality forages with a good energy profile or supplementing with co-products that are energy-rich. In general, we want to keep protein levels above the minimum levels for our age and stage of females.
As an example, for a 1,400-pound cow with 30 pounds of milk in her third trimester, this would be 8 percent crude protein on a dry matter basis – or 2 pounds if you are feeding 32 pounds of feed that is 85 percent dry.
Keep in mind that when you feed protein, you are first and foremost feeding the rumen microbes. An increase in the minimum amount of protein will generally cause an increase in forage intake as the rumen will be more active and digest forages more thoroughly.
However, coarse or mature forage with a high amount of lignin will process more slowly due to low digestibility. Knowing your forage quality and profile again becomes very important. Overfeeding protein can be expensive, so take this into account when you are pricing your cattle diets.
Some co-products contain substantial digestible fiber, which is used as energy by the rumen. Such products would include distillers grains, wheat midds and soybean hulls. These feeds are all currently very reasonably priced, but delivery costs should be factored in when pricing your feeds.
Sometimes, the most cost-effective supplemental feed is a home-raised early cut alfalfa. All of these feeds generally have a healthy protein profile to keep the rumen well-producing.
Corn grain can also be fed, but caution must be exercised here as grain is high in starch energy and can compromise rumen function. Forage digestion decreases substantially when grain exceeds 4 pounds per head per day. If supplementing with grain, start slow at 1 pound per head per day and move up from there over the course of a couple or several days.
Corn should be fed at a maximum addition level of 3 pounds per head per day and should be delivered at the same rate every day, preferably mixed with forage to assure uniform intake by all cows.
In order to keep those hefty winter feeding costs down and protect your long-term cow investment, the best practice is to assess your cows, develop a diet to meet her emerging needs, keep ahead of the stress from blasts of winter and re-assess your cows regularly.
Calving will be here before we know it, and our well-planned winter diet practices will pay off in her rebreeding performance in the upcoming year.
PHOTO 1: Producers need to remember that for every degree Fahrenheit below the “lower critical temperature” threshold, beef cattle require 1 percent more energy in their diet.
PHOTO 2: Assess cows at the beginning of their third trimester or three months before they calve to determine the type and amount of added feed. Photos by Cassidy Woolsey.
- Area Extension Specialist
- Central Grasslands Research Extension Center - North Dakota State University
- Email Fara Brummer