Cold weather and cows

By the time you see this, the world-famous weather prognosticating groundhog Punxsutawney Phil has trundled out to do his job. We’re either in for six more weeks of winter or not. Regardless of what the rodent indicates, weather records tell us that it’s about the coldest time of year. And that means spring-calving beef cows are getting close to dropping calves.

For feeding plans, that means its important to remember that the days just before Christmas, when cows were in mid-gestation and had lower nutrient requirements, are gone. In these cold, pre-calving days, there are a couple of things that certainly require attention: 1) how weather affects the cow’s nutrient needs; 2) barns and their proper ventilation. If you’re calving outdoors, on pasture or in the woods, lack of ventilation obviously is less of an issue. It’s excessive ventilation that you’re worried about.

When cattle are in an environment where they do not need to spend energy to warm themselves (cold stress) or cool themselves (heat stress), they enjoy what is called the thermoneutral zone. The colder end of the thermoneutral zone is the “lower critical temperature.” At points below this effective temperature, a cow requires additional energy to maintain its body temperature. If cows have a dry winter coat, the threshold at which they begin spending energy to stay warm is considered 32º F.

As a general rule, when the ambient temperature drops below the lower critical temperature, cattle will experience a 1 percent increase in energy requirement for each degree the temperature, or wind chill, drops below 32º F.

As an example, if it is 26º out with no wind and a cow is dry, she will require a 6 percent increase in energy requirements (32º - 26º = 6). If you are unable to protect the cow from getting wet, the math can get ugly. A wet coat increases the lower critical temperature to 60º. A cow outside in sleet at 26º suffers a 34 percent increase in required energy (60º - 26º = 34). And because her coat is wet, instead of every degree raising the energy requirement by 1 percent, it goes to 2 percent. Her energy requirements are fully two thirds higher when wet. She can not eat enough feed to maintain her weight.

The best that can be done from a feed perspective is to increase the amount of dietary energy available to cattle during cold weather. The most direct way to increase energy is to add concentrate/ionophores to the diet. In a pinch you can allocate your hay supply, saving higher energy hay for colder times of the year. Or saving it for expected wet periods. You’ll have to make the call depending on your hay supply and weather conditions. Regardless, protecting cattle from adverse weather conditions drastically influences the animal’s feed needs and reduces your feed bill.

Temperature is not the only factor to consider. Earlier in my career, I worked in Iowa, where we worried more about air quality for cattle enclosed in barns. Up there, ensuring adequate air exchange was a critical issue. In tight barns, adequate air exchange is required to control humidity, condensation and ammonia levels. Poorly ventilated barns typically increased health challenges for the herd.

In a peaked-roof barn, the simple solution is to make sure there is an open ridge at the peak. The opening allows warmer, moisture-laden air to rise up and out of the barn. The concept applies to mono-slope barns as well. An opening high in the barn allows warm air to carry moisture out.

The trick is to allow for good air exchange without causing cold drafts. In my experience, it is better to minimize barn humidity than maximize barn temperature. You should protect cattle from the weather, but not at the expense of air quality.

Another factor to consider in winter feeding is the cow’s protein requirement. While protein requirements won’t increase in the drastic manner that energy requirements do, feeding protein is still important in winter. A cow needs protein for her growth, maintenance and fetal development if she is gestating. Moreover, rumen function is influenced by nitrogen/crude protein. Nitrogen/protein deficiencies cause reduced fiber digestion, which tends to amplify energy deficiencies during adverse weather conditions. When forage digestibility is reduced, forage intake will be limited.

More in the Feb 2016 Issue of Today's Farmer Magazine



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Supplement poor forage

Feeding a protein supplement maintains animal performance

About every year there are periods when the forage on hand isn’t high enough quality or in adequate quantity to meet your cow herd’s needs. You can’t be sure just which time of year, but you can count on challenges from pasture dormancy, drought, pest infestations, blizzards, all things that can make you operation short on the energy component of feed.

Of course, as a beef producer, it warms your heart to see cows out making a living grazing forages—just turning grass into beef without interventions from management or your checking account. But that warm heart sometimes gets in the way of cold business sense. You will usually benefit economically by correcting nutrient deficiencies sooner than later. For example before you begin to see body condition losses. Doing so substantially improves animal performance. And poor animal performance gets into the checkbook, too. Poor performance from a deficit in energy for your herd leads to decreased conception in cows; reduction in milk production and lactation length; loss of body condition scores; and reduction in fetal growth.

It can also bring on a reduced tolerance to stress, which invites disease, parasites and calving challenges.

Addressing forage/energy deficiency can be tedious. A straightforward solution is to feed a supplement which is low in protein and high in energy. Corn, for example. You can supplement the additional energy in a number of ways: tubs, blocks, liquid, cubes, pellets, mash, etc.

Your cost will vary. And your herd’s potential for shrink and the ease of handling will vary. Fundamentally the objective is to get supplemental feed that directly addresses the limiting factors in the cows’ diet. Of course, you have to consider your labor costs, time and delivery options. These are too often ignored to the detriment of your payday. Still, if you study the economics of these factors are combined with the a range of feed nutrient values, you can find the best value for the money. For example, a 20-percent protein hay might have a lower unit-of-energy cost and/or protein cost than a supplement tub. But, if you are driving 50 miles to do chores, tubs make a lot of sense.

Also consider how the cows will handle the diet. Ruminal forage digestibility can be reduced when high starch levels are introduced to the diet.

Fiber digestibility increases as an all-forage diet increases in starch. Fiber digestibility reaches a peak/plateau at about 0.25 percent of bodyweight. If you are feeding corn, that means feeding 0.375 percent of body weight to get to the right spot. At higher levels, the energy concentration increases, but the fiber digestibility declines. At ever higher levels of grain, this becomes less of an issue because the amount of forage in the diet is dropping.

However, one concern with lower forage digestibility is that the rate of passage through the animal will take a lot longer.

In turn, the rumen fills with forage that can’t be pushed through the system fast enough for adequate forage to be consumed. You can help the process by mechanically chopping the forage.

Another constraint to forage digestibility can be a forage with a low crude protein content. When forage protein is below 8 percent, the protein/nitrogen in the rumen can limit rumen bacteria growth, which in turns limits forage digestibility. The rumen microbial population needs adequate nitrogen to function well. They get that nitrogen from protein/nitrogen feeds. Therefore, adding a protein supplement to the diet can increase forage intake in many cases and alleviate or reduce the energy deficiency problem. This is particularly the case where your forage inventory is abundant but slightly high in fiber and low in protein. Controlled studies indicate that the intake of lower quality forage can be increased 20 to 60 percent, and forage digestibility can be increased by 5 to 15 percent by supplementing rumen-available protein.

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Early weaning tips

Early weaning can be a strategic benefit to your herd, giving cows a quicker rebound and earlier breedback. Research shows, too, that calves fed earlier in their life have increased carcass quality.

In simple terms, early weaning beef calves is a management practice that removes calves from the dam and replaces her with direct feed. This allows cows to scavenge to meet their reduced nutrient needs with the intent of maintaining, if not increasing, body condition.

Recent research on early-weaned beef calves has focused on the carcass quality of calves following early weaning (at about 90 to 150 days). Results indicate that more rapid growth in early-weaned calves results in higher marbling scores compared to calves weaned at 205 days. Early-weaned calves will be slaughtered at a younger age. And, aside from higher carcass quality, they tend to have better feed-to-gain ratio.

Marbling development in calves is influenced by management and nutrition. Given that fat cell development is influenced by nutrient intake, intramuscular fat formation may be stimulated during periods in which nutrient intake exceeds what can be used for muscle growth. This is likely the cause for increased marbling scores in early-weaned and well-fed calves.

When I mention these results to producers, I get the question: “With these benefits, why not always wean calves early? If the practice saves feed in a drought, then in a normal year, I could run more cows, right?”

I remind producers that the benefits of early weaning are accompanied by some challenges.

Removing calves from the dam early, coupled with nutrient-dense diets can result in lighter carcass weights, greater number of days on feed and increased feed costs. This is particularly the case for medium- to smaller-framed cattle. In light of the dramatic increase in feed costs from about 2008 to 2013, producers actually went the other direction. They sought to use forage and by-products during a post-weaning growing/backgrounding/stocker phase before putting the cattle in a feedlot.

The goal in that case was to exploit slower growth rates and decreased inputs. Producers wanted to be able to afford the feed bill. Feed costs, at least for now, have realigned, and early weaning may fit more operations.

To use early weaning as a management strategy, you should focus on a few objectives. In your forage-based cow/calf production plan, you want to 1) increase marbling; 2) achieve desired replacement animal growth and development; 3) improve mature cow reproductive efficiency.

To achieve these goals consider these management practices:

  • Early weaning must occur before the start of the breeding season to achieve all possible reproductive benefits for the dam.
  • Calves should be at least seven weeks of age when weaned.
  • Aim for breeding the yearling heifers 30 days before the mature cows. That way their calves will be old enough to early wean at the start of the regular breeding season the next year.

Early-weaned cows will voluntarily consume about 30 percent less dry matter after the calf has been removed. Their decrease in dry matter intake coupled with their concurrent decrease in nutrient demands translates to a 45 percent increase in nutrient efficiency.

Early-weaned calves grow well on forages. Forage should be readily available, of high quality and combined with concentrate supplementation at 1 percent of body weight per day. MFA Cadence is a good option. When high quality, grazable pastures are not available, consider using Cadence 25C or 50C to provide the required intake of energy and protein.

Keep in mind that early-weaned calves are vulnerable to parasites. You need to provide adequate fly control and treat for parasites.

Depending on conditions, it might be advantageous to move the early-weaned calves to a drylot and feed them. And implating is beneficial.

When received into the feedlot at the time of normal weaning, early weaned calves will be heavier and have greater feed efficiency compared to their normal-weaned herd mates. This is an important factor if you are considering whether to retain ownership through finish.

Here are specific feeding guidelines offered by Oklahoma State University’s David Lalman.

  1. Follow the 10 percent rule. Never increase or decrease the amount of feed offered by more than 5 to 10 percent.
  2. Always allow one day between increases or decreases in feed offered to allow animals an adjustment period.
  3. If the bunk stays empty more than an hour for two consecutive days, increase the amount of feed by 5-10 percent.
  4. Dry feeds may be fed once daily.
  5. High moisture feeds may need to be fed twice daily to avoid spoiling in hot weather and freezing in cold weather.
  6. Animals not being fed enough will engorge when fed. This leads to acidosis and the “yoyo” effect of overeating and under-eating. This dramatically decreases animal performance and animal health.
  7. Before cold fronts, animal feed intake increases dramatically and decreases after the front passes.
  8. Feed should be fresh!
  9. If animals rush the bunk when fed, they are probably being underfed.
  10. If animals have no interest in coming to the bunk when they are fed, they are probably being overfed. Same if the bunk contains spoiled feed.
  11. Bunks containing spoiled feed or “fines” should be cleaned out.
  12. If fines are constantly a problem, consider adding molasses, silage or other wet feeds to the diet to decrease the sorting of mineral and vitamin supplements.
  13. Clean waterers are necessary to maximize feed intake.
  14. Many of these rules also apply to self-feeders.


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Feeding for health in a new era

A major shift in livestock production has arrived. At the end of 2016, producers will be required to have a veterinary feed directive before purchasing and feeding antibiotics. Ionophores and non-antibiotic feed medications won’t require a VFD. The idea behind use of VFDs is to make sure producers use antibiotics only for treating cattle that have been diagnosed with a condition treatable by antibiotics. Sub-therapeutic treatments are no longer a management option. The rules come as law makers heed public opinion about antibiotic use in livestock production.

Under the new rules, only veterinarians can issue VFDs and they must do it within the context of what USDA is calling the veterinarian-client-patient relationship (VCPR). In other words, the vet will be required to engage with the livestock producer, know and visit the operation and provide for follow-up care. Furthermore, the vet will be required to document VFDs.

Prior to the regulations taking effect, MFA’s feed division developed feed and minerals that use phytogenic technology to provide multiple benefits to livestock. It’s branded as Shield Technology and is available in a wide spectrum of MFA feeds. While research on these formulations began in part as a way to feed animals designated for specific export markets, the benefits of Shield make feeding these formulations an obvious alternative to sub-therapeutic doses of antibiotics.

“The new regulations will change the way that many producers do business,” said Mike Spidle, director of product sales and feed. “The good news is that MFA had already been working on non-antibiotic feed formulations that keep livestock healthy. You don’t need antibiotics if you have healthy animals. With Shield Technology, you don’t need a VFD,” he added.

Spidle said the European feed industry lead the way in feeding phytogenics. With Europe’s stricter rules on antibiotics, livestock producers there have been feeding phytogenic ingredients for decades.

What’s a phytogenic ingredient? MFA’s director of ruminant nutrition, Dr. Jim White, said the term covers a wide spectrum of specialty ingredients. “Basically, a phytogenic additive is a non-antibiotic growth promoter. It’s typically going to be a plant extract or compound that’s been proven to benefit an animal in a particular way. Depending on the ingredient, you’re looking at natural, non-regulated compounds that show antimicrobial, anti-viral or antioxidant effects in the animal.”

White pointed out that phytogenics are usually used in combination to get the desired effect.

When we formulate feed with phytogenic components, the goal is to improve animal health so they don’t get sick. Hopefully, you can avoid antibiotics completely. We’ve focused on essential oils, specific carbohydrates and prebiotic fiber in Shield.”

White said that essential oils have been shown to modulate rumen fermentation, making the rumen less vulnerable to harmful bacterias and fungi. “Technically speaking,” he said, “the oils diffuse through cytoplasmic membrane into the bacterial cell and cause a chain reaction that ends with the bad cell dying.”

The specific carbohydrates at work are mannan-oligosaccharides and glucans that target gut health in the animal.

Mannans move through the gut where they interfere with the infection process because pathogenic bacteria adhere to the yeast cell rather than the villi, the little “fingers” of the intestines. Troublemakers such as E. Coli and Salmonella have been shown to be susceptible to mannan-oligosaccharides.

“These are the ingredients we’ve been using in MFA’s Ricochet products,” said White. “We’ve gotten good feedback from producers from these products. What we see is improved calf and dam performance through improved immunity in the cow and better passive transfer to calf.”

In the field, failure of passive transfer is a major contributor to calf sickness. A calf’s immune system doesn’t fully activate until a few weeks after birth, leaving it vulnerable if the dam didn’t provide good colostrum. “Anything we can do to stack the deck for better passive transfer is an advantage,” said White.

Beta glucan, which is an extract of yeast cell walls, is an immune system booster. “You can look to the human supplement business to see the popularity of beta glucans. People buy it by the gob,” said White. “It’s a immune modulator. The way it boosts the immune system is through a beneficial effect on white blood cells, which helps stave off bacterial and fungal infections.”

MFA director of Animal Health, Dr. Tony Martin, said that formulations with phytogenic ingredients show great promise as a tool to keep livestock healthy. He added, though, that like any tool on the farm, phytogenics are just one part of good management. “The things that make livestock most profitable are the fundamentals. Healthy animals make money. So you want to carefully manage your vaccination program. You want to consider hygiene for the herd. Consider how you reduce stress from the environment and handling. And yes, certainly, you want to get the right nutrition to livestock, especially at critical times in their development. If you reduce all the things that can challenge health, your herd benefits greatly.”

“I’m excited about the prospects that Shield brings to producers,” Spidle said. “We’ve seen good results from research, and we’re doing more. If you can feed something that reduces open cows, that reduces scours in calves, that makes livestock more feed efficient, why wouldn’t you? We understand more and more that fetal health affects the entire life of a calf. Shield Technology is delivering health benefits to the dam and the calf. And on top of it all, if you’re feeding Shield products, your livestock are free and clear in more world markets.”


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Fetal nutrition has long-term effect

Evidence continues to mount that you should start managing calves before they are born. That’s a tough thing to do, you say, but if you think about it, it’s not. “Fetal programming,” or developmental programming is the idea that maternal stimulus at critical times in fetal development has long-term impacts on the offspring.

As beef producers, you are used to hearing about studies to see how nutrition impacts health and productivity of a calf. Traditionally, these studies have been post-natal, or after the calf is born. This makes a lot of sense. At that point, the animal is identified as an individual, its situation (its genetics and environment) is unique.

But how did it do up until birth? Did it get proper nutrition? Was its immune system bolstered? While maternal nutrition during pregnancy plays an essential role in proper fetal and placental development, less is known about how maternal nutrition impacts the long-term health and productivity of the offspring.

A cow in gestation is eating for two. Clearly, prenatal growth is sensitive to the direct and indirect effects of maternal diet—basically from just after conception.

In general terms, though, herd management has evolved as if undernutrition of a pregnant cow during the early stages of fetal development isn’t much to worry about. After all, what nutrient requirements could a fetus really need during the first half of gestation? At least, this was the conventional wisdom back when I was in grad school. That’s because some 75 percent of the growth for a ruminant fetus happens in the last two months of gestation. But, according to work from K.A. Vonnahme at North Dakota State University, “it is during this early phase of fetal development that maximal placental growth, differentiation and vascularization occurs, as well as fetal organogenesis.” All of these are critical for fetal development.

If that early growth is challenged, it can compromise the animal’s longterm performance. In other words, not only is neonatal health compromised, but the subsequent health may be “programmed” as offspring from undernourished dams have been shown to exhibit poor growth and productivity and also to develop significant diseases later in life.

In commercial cattle production settings, undernutrition often occurs during gestation—especially during the first two trimesters. This results from either low feed reserves or management practices that result in cows losing weight during late fall and early winter.

This theory of developmental programming has been experimentally challenged and verified using several animal models, particularly rats. Here is where it gets tricky. Variations in the duration and severity of maternal undernutrition do not always result in a reduced birth weight. Physiologic alterations such as glucose intolerance, skewed growth patterns and alterations in carcass characteristics have been reported. Thus, birth weight alone may not be the best predictor for calf survival and productivity. Research at NDSU shows that beef cows bred to the same bull and carrying female fetuses delivered calves of similar birth weight in situations when they were fed adequately and when they were underfed.

According to Vonnahme, previous studies of sheep and humans have demonstrated that an extended period of maternal underfeeding during the first half of gestation results in relatively normal birth weights. However, it leads to increases in the length and thinness of the newborn. The practical significance of fetal programming lies in the associations between reductions in maternal nutrition during early gestation and the risk of abnormalities in muscle function, mineralization of bone and organ function. Unfortunately, at present, little is known about the specific nutrient induced changes that end up causing poor development later in the animal’s life.

Research does show that feeding pregnant rats a low-protein diet results in lifelong elevations in blood pressure in the offspring. Increases in fetal blood pressure are known to result in alterations in blood flow to the lungs, and as a result, to long-term lung function.

That’s just rats, of course. But consider the fact that bovine respiratory diseases make up the majority of illness and death loss in feedlots. According to Vonnahme’s roundup of the research, historically, 15 to 45 percent of feedlot cattle have been affected with bovine respiratory disease (BRD). In fact, some 1 to 5 percent of total cattle placed on feed traditionally die of BRD. Respiratory disease alone accounts for 44 percent of deaths in beef feedlot cattle. It is possible that gestational nutrient restriction could increase susceptibility of cattle to respiratory disease during later life, especially in the feedlot.

Aside from disease, Vonnahme’s research suggests that long-term muscle development is also affected by maternal nutrition. “Growth restriction seems to be especially important when fetal muscle development is adversely affected. Skeletal muscle has a lower priority in nutrient partitioning compared to the brain and heart in response to the challenges to the fetus during development, rendering it particularly vulnerable to nutrient deficiency,” he reported. Basically, maternal growth is critical for muscle development because that’s when the number of muscle fibers is established. Muscles grow after birth, of course, but the base number of fibers is already set.

According to Vonnahme, “steers from cows which were nutritionally restricted during gestation had lower live and carcass weights compared to steers from adequately fed cows at 30 months of age.”

Vonnahme pointed out that retail yield on the carcasses, based on fatness, were greater in the steers from nutritionally restricted cows, indicating that while growth may be hindered in offspring from cows receiving low nutrition during pregnancy, ability to accumulate fat is not. The quality grade is another matter. MFA has developed a nutrigenomic technology with Ricochet that will focus on these issues. It will be available later this year.

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