Brassicas require thoughtful grazing management

Interest in grazing brassicas is on the rise. In effort to extend the grazing season, producers are planting more turnips and radishes. And, as sod-seeding techniques are further fine-tuned, I expect to see even more livestock grazing brassicas.

Brassicas such as turnips or radishes produce high yields of nutrient-rich leaves and roots. They make good grazing. These crops have been helpful at two critical time periods in the year, midsummer and late fall to early winter. Summer-planted turnips may be the best grazing option for late fall and winter. But, like everything else, they can cause problems. Problems that might arise from feeding turnips include hemolytic anemia, polioencephalomalacia, pulmonary emphysema, nitrate toxicity, infertility, bloat and goiter. That’s a nice list of scary stuff, but you can avoid most problems with proper management.

Basic strategies for managing brassica grazing are similar to how you handle alfalfa or lush spring pasture.

Don’t start feeding turnips suddenly and extensively. Instead, let cattle adapt to a richer diet by feeding high quality forage for a couple weeks before grazing turnips.

When you do introduce the herd to brassicas, allow access for just a few hours a day. While grazing turnips, continue to provide a dry forage source like grass hay or corn stalks.

You can restrict grazing area to limit access as well as encourage full plant consumption.

Use an electric wire or tape to stripgraze. This will encourage animals to eat the leaves and bulbs.

Provide a mineral supplement. Providing a supplement with monensin (Rumensin) improves the energy value of the diet. Feeding monensin is helpful in reducing the incidence of pulmonary emphysema (ABPE). ABPE is most likely to occur when mature cows quickly move from a coarse forage base to a lush, high-quality forage base. It’s technically caused by the metabolism of tryptophan, an essential amino acid. In the rumen, lactobacillus bacteria convert tryptophan to 3-methylindole, a toxic compound that causes lung damage, edema and emphysema.

You may hear about choking risks from brassicas like turnips, but the only case I have ever verified was on drought-stricken turnips that had bulbs the size of carrots, and the animals had limited feed availability. Cows do chew.

Turnips can be very productive, they grow fast and can be grazed as early as 70 days after planting. They reach near maximum dry matter yields at 80 to 90 days. The protein content will be high in the leaves-often in the mid 20s on a dry matter basis. Leaves are 10 to 18 percent of the total plant mass. Bulbs make 82 to 90 percent of the mass.

If you plan to grow turnips or other brassicas, your fertility program is best determined by soil test and MFA agronomist recommendations. My experience is that phosphorous and potash recommendations are similar to a small grain crop, and 70 to 80 pounds per acre of nitrogen is needed.

For a source of turnip seed, MFA offers the purple top white bulb forage turnip, product #2612540 and the Barkant turnip, product #2612585.

A healthy immune system is led by a balanced ration and planning for stress

Most beef herds are exposed to multiple health challenges. Viruses, bacteria, parasites and toxins can come from air, water, herd mates and wildlife. Stress factors such as weaning, co-mingling, handling, transportation and extreme temperatures exacerbate these challenges and can further suppress the immune system. Optimal nutrition is the first defensive measure. Optimal nutrition supports health functions and sends the animal toward its top genetic growth potential.

The immune system is composed of three general defense systems. The first two are called non-specific, in that typically the “defense” cells are indiscriminate against most foreign substances. First are skin and mucous secretions within the body. The second involves white blood cells from the blood stream and lymphoid tissues. These cells and sub-cells are released when there is injury to the body or by parasites and byproducts from allergic reactions. The cells seek and destroy harmful bacteria to prevent/fight against infection.

The third defense system is yet another set of white blood cells called T and B cells, but these are specific in nature. The primary function of these cells is to build specific ‘memory’ for the body against a particular invading virus. For example, giving a vaccine for BVD (Bovine Viral Diarrhea) is immunizing the body against invading BVD viruses. The T and B cells will act by producing specific antibodies that will bind to BVD only and will continue protecting against the organism.

It is a proficient and complex system. For it to work correctly the right nutrient profile for the animal is critical. All the basic nutrients have been shown to impact immune competence, including protein, energy, vitamins and minerals. For ruminants, by far the most important are protein and energy. Energy is the power source for the synthesis and function of immune cells, while protein regulates and provides structural element for cells and antibodies. During times of stress protein and energy are particularly important because stress can reduce intake, thus furthering the suppression of immunity functions through low intake of feedstuffs. When stress situations are impending, for example at weaning, supply a protein- and energy-dense feedstuff designed to compensate for low intake.

The roles of vitamins and minerals overlap for proper immune function. While there are several vitamins that are needed to support immune function, vitamins A and E need to be supplemented in the diet, whereas vitamins B6, B12 and C are supplied by rumen bugs and body tissues in sufficient levels. Multiple studies have demonstrated that vitamin E will increase the function of neutrophils (white blood cells), which are important scavengers of non-specific immunity.

Although several minerals are important for overall body function, zinc, copper and selenium are specifically important for the immune system and should always be offered to cattle in amounts that supply their requirements. Zinc is a well-studied trace mineral on immunity, particularly in stocker and feeder cattle. Zinc is essential in the formation of enzymes that work within cells thus making it vital for cell production, growth and function. A solid immune system is dependent on rapidly dividing cells and cell movement, therefore, a deficiency of zinc can have negative implications on animal health.
Negative interaction between trace minerals can also tie up availability of these nutrients.

University research recently found diets high in sulfur reduced retention of trace minerals copper, zinc and manganese in steers after only 20 days. Corn byproduct commodities, such as distillers grains and gluten feed, are high in sulfur. Thus, with diet high in these ingredients, consideration should be taken to insure there is adequate supplementation of the negatively affected elements.

Severe copper deficiency is generally due more to antagonistic effects of other minerals and/or organisms that make copper less bioavailable to the animal. Dietary molybdenum, sulfur and iron in excess can inhibit uptake of copper digestively, in tissues and bloodstream of ruminants. Consumption of heavy endophyte-
infected pasture starting mid-summer causes a reduction in overall intake, thus causing a deficiency of copper through simple lack of feed consumption.

During times of increased metabolic or immunological strain, overproduction of free radicals called reactive oxygen species (ROS) are formed as a normal end product. The over-accumulation of ROS can result in substantial damage to the animal’s tissues. Vitamin E and selenium are both highly effective antioxidants that will counter the effects of excessive ROS by preventing cellular dysfunction or premature protein degradation.

You should determination risk levels for your herd and plan for nutritional compensation during the most stressful periods. It will help you build an effective barrier against health challenges. The cash value of beef animals is at all-time highs. Along with those record prices, the return on supplementing the right nutrition to support your investment is at its peak.

Mark Epp is Ruminant nutritionist for MFA incorporated. Questions? Contact This email address is being protected from spambots. You need JavaScript enabled to view it..

A few thoughts on stockpiling fescue

In the love/hate relationship you have with fescue, one characteristic that should be tallied on the “love” side of things is that fescue is well adapted for fall stockpiling. It allows you to graze longer into the winter.

In a stockpiling system, fertilizer is applied in late summer and forage is allowed to accumulate until it goes dormant. Grazing the pastures usually starts in early winter. For stockpiling fescue, MFA forage specialist David Moore recommends application of fertilizer between Aug. 20 and Sept. 15. The application consists of a third of the year’s nitrogen, all the year’s phosphorus and half of the year’s potassium plus 5 pounds of sulfur.

If you don’t have a soil test for reference, in general terms, the application would be 40 pounds N, 50 pounds P and 75 pounds K with 5 pounds of sulfur.

Moore told me, “This should promote good fall pasture and stockpiling as well as support an early wakeup of healthy grass that is poised to grow well the following spring.” His mantra, which you can read more about on page 14, is “Don’t feed the weeds. More grass equals more beef.”

For the most appropriate fertility recommendations on your pasture, you should get a soil test. And, going forward, consider grid sampling and using some level of variable-rate application to get the right fertility to the places in your forage program that most need it.

Putting nitrogen on grass pastures is a bet that you cannot lose. Let me explain: the typical response is that 1 pound of nitrogen gives an additional 20 pounds of forage dry matter. There are some trade-offs: the earlier you start stockpiling, the higher the yield response, but stockpile forage will be more mature and lower in nutrients. And, rain is required.

When talking about stockpiled forage, I like to think of cows as self-propelled forage harvesters, keeping my labor down to moving fences. The way to achieve the highest utilization of the stockpiled fescue is to manage the pasture by frontal strip grazing. With this method, you will be managing cattle grazing behavior. By restricting grazing to strips, you’ll get a more complete forage harvest. In most cases, a new strip is offered every other day. Using this method, harvest efficiency can be better than 70 percent (a similar use efficiency to hay systems).

What makes fescue a high candidate for stockpiling is the fact it retains its nutrient value better than other forages and manages to stay standing. The feed value of stockpiled fescue is usually close to or greater than the nutrient requirements for dry beef cows, and with luck and good management, it comes close to covering energy and protein needs for wet cows of moderate milking ability.

If you are trying to put weight on calves, results might differ. When you test the stockpiled forage, results might indicate you ought to be getting a higher average daily gain than what you actually get. The traditional nutritionist excuse for slow calf gain on stockpiled fescue is to blame endophyte infection. Fescue infected with endophyte will slow intake and performance. If you need to push calves on stockpile, they will respond well to Cadence, Cattle Charge or Full Throttle.

University of Missouri agronomists Rob Kallenbach and Craig Roberts reported that stockpiled fescue typically will have a nutritive quality high enough to support wintering beef cows. Their research show average values of 12 percent crude protein at greater than 36 percent acid detergent fiber and 56 percent neutral detergent fiber. That would be a relative feed value of at least 100 with in vitro digestibilities in the 70s. Of course, there is a tremendous year-by-year variability to nutrient values of stockpiled forages. Snow cover will set you back, and ice is a plan wrecker.

Supplementing the stockpiled forage comes down to an art. You want to balance available stockpile with hay supplies and the cost of supplements along with the body condition or rate of gain you have targeted. The response to supplementation will depend on the availability and quality of the forage.

As a general rule, increasing the degradable protein and energy on stockpiled fescue will improve daily dry matter intake. Using ionophores such as Rumensin and Bovatec will significantly improve animal performance and help cows hold their body condition. Feeding a vitamin and trace mineral source will ensure the herd’s nutrient requirements are covered. You can piecemeal a supplementation or feed something like Cattle Charge as a single-product solution. If you have endophyte-infected fescue, the supplementation helps dilute or reduce the ergot alkaloid load in your animals’ bloodstream.

Dr. Jim White is the Director of Nutrition at MFA Incorporated. Questions? Contact This email address is being protected from spambots. You need JavaScript enabled to view it..

Fire isn’t the only worry–hot hay damages nutritional value

Depending on the operation, hay production can be a high priority or an afterthought shoved out of the way by spring planting. From a feed value perspective, though, it is crucial to minimize risks and losses in the field. It is essential to maintain forage quality and to protect the forage from storage losses.

It is spring. And, certainly, precipitation damage can reduce the quality and mass of harvested forage. Harvests of hay are frequently complicated by poor drying and the threat of unexpected rainfall. You often are forced to choose between baling hay before adequate drying has occurred or subjecting wilting hay to rain damage.

For hay that is not adequately dry, a potential problem is spontaneous heating. This process occurs when plant sugars are respired in CO2, water and heat up via microorganisms–principally fungi.

Traditionally, hay research has used small square bales to study how hay reacts to different conditions. However, due to cost and the limited labor available to handle conventional rectangular hay bales, many producers have been forced to consider larger bale sizes. Generally, larger bale sizes are more prone to heat spontaneously and require a reduced threshold moisture for acceptable storage. In addition, round bales show more measurable effects of spontaneous heating than are usually seen in a small rectangular hay bale. In other words, you’ll more often see brown spots in the middle of big bales.

Of course, brown spots aren’t good, but a hay fire is a total loss. A hay fire leaves you less worried about the nutritional value at stake and more concerned about the loss of a barn.
From personal experience, I can attest that it is really important to know the coverage and limits of an insurance product before a fire, rather than finding out the coverage after a fire. So, let’s concentrate on prevention.

It’s wet hay that causes fires. With adequate moisture to maintain the relative humidity of the air in the hay mass at 95 percent to 97 percent, heat generated by plant enzymatic activity and microbial growth may push temperatures to 160° F within a few days. This progression may take several weeks.

Above 160°F, oxidative chemical reactions are responsible for additional heat generation. This auto-oxidation greatly increases the potential for further rapid increase to combustion temperatures. In some research I’ve looked at, mixed hay at 44 percent moisture took a month to reach a temperature of 195° F, but then increased to 330° F in only three more days. Soluble carbohydrates were almost completely eliminated in the hay that reached 330° F.

Spontaneous combustion requires large quantities of oxygen. Thermal conductivity of dry hay is lower than moist hay, so heat transfer to the outside of the bale becomes progressively less effective as the hay dries. Thus, hay temperatures may increase rapidly after much of the moisture has been removed. Spontaneous combustion occurs near the outside of the bale because oxygen levels in the interior are reduced by microbial respiration.

To avoid hay fire damage
•    Adequate drying is the best solution; dry hay won’t produce heat-inducing fungi
•    Do not stack hay close to power lines, electric fences, trees or buildings
•    Do not park equipment close to hay stacks
•    Ensure adequate separation of stacks–use multiple stacks to reduce the chance of larger loss, especially with suspect hay
•    Exclusion of oxygen is an option: make silage
•    Use anti-mycotics (hay preservers) to allow more time for the hay to dry and knock down microbial growth

Fires are obvious. But bales that don’t get hot enough to burn can still deliver a non-visible loss, nutritionally speaking.

Hay that has gotten hot will test higher for crude protein than what the animal results indicate. It will look brown—and more brown if it was hot for a long time. You’ll also see this process in hay silage crops. They’ll come out looking and smelling like chewing tobacco. In corn silage, you’ll see heat-damaged kernels, which are usually associated with drier or poorly packed silages.

This is significant nutritionally because of what we call ADICP, the crude protein recovered within insoluble acid detergent fiber.

The browning reaction is important because ADICP has very low bioavailability to cattle. That’s what I mean by hay testing higher for crude protein than the livestock indicate.

If you are feeding heat-damaged hay or haylage, expect animals to digest the material at a higher rate (the rate of passage declines and digestibility increases). This often reduces energy intake on the animals, which is a big deal if you have cows that are on the feed to maintain their weight.
ADICP is commonly used as an indicator of heat damage; as hay heating increases, so does the ADICP. And while research is mixed, in general terms, you can count on crude protein in the hay plummeting if it has gotten hot.

Prevention is the best choice.

Dr. Jim White is a MFA's ruminant nutritionist. Contact us at This email address is being protected from spambots. You need JavaScript enabled to view it.