K-State Research and Extension

“Antimicrobial Resistance”

 by Chris Reinhardt, feedlot specialist

 A very smart scientist once said, “Anyone who claims they fully understand antimicrobial resistance simply hasn’t studied it enough yet!” Development of antimicrobial resistance by bacteria is a very complex issue that even the brightest in the human health and animal health communities do not fully comprehend, let alone can unequivocally say it’s an issue for which they have identified definitive causes and solutions. So if a lay person, a talking head, or a blogger claims to have all the answers, we’re best off to take their opinion with a grain of salt and keep searching.

That said, there are few issues with so broad a gap between the potential future human and animal health ramifications and our collective impotence at devising truly effective control practices. We know that unchecked growth in resistance could be disastrous, yet none of the smart people who study this and who I trust can say with any degree of certainty that any of the proposed measures—including complete abolition of use—will have any significant impact on resistance.

In light of that uncertainty, some argue for a “stay the course” approach until science and understanding can provide some sure solutions. Others suggest a “precautionary principle”, choosing instead to err on the side of logic, even if that logic is unproven, hoping that some action is better than none at all.

So (1) we lack comprehensive understanding of the underlying science behind the issue, (2) we lack a consensus among reasonable and influential parties as to practical and useful solutions, and (3) we lack an even remote illusion that we can control what happens in other parts of the world in which there is less robust oversight of antimicrobial use in humans and animals and of food production practices in general, and oftentimes greater and more widespread prevalence of infectious diseases which encourages the use and often abuse of any available antimicrobials.

The point is that if use and abuse of antibiotics do in fact perpetuate growth in bacterial resistance to antimicrobials, there is concern regarding the current inability of some countries or regions of the world, due to insufficient funding and infrastructure, to police any future policy designed to limit use in order to control the growth of resistance.

H.L. Mencken, another smart person, said, “For every complex problem there is an answer that is clear, simple, and wrong.” I paraphrase and shorten this to, “Complex problems have no simple solutions.” We’ve got to do the seriously heavy lifting to get to meaningful outcomes. Einstein is credited for saying, “We cannot solve our problems with the same thinking we used when we created them.” I doubt Alexander Fleming in 1928 knew the next-level challenges that would arise nearly 100 years after his discovery of penicillin.

The good news is that the debate continues, and the smart, reasonable-thinking, people are at the table, here and abroad, trying to hammer out solutions which are not clear or simple but which hopefully will be right long-term for human health and for food production, which will be forever inextricably linked.

“Shade for Developing Bulls”

by Chris Reinhardt, feedlot specialist 

When feeding young bulls for sale, a compromise must be made between absolute maximum performance and long-term health of the bulls.

If only short-term performance were the goal, we’d feed a finishing diet and short-term ADG would be maximized; however, we would suffer a significant number of losses due to laminitis and other acidosis-related ailments. Therefore, we try to strike a balance by including in the diet an abundance of good quality forage in addition to grain and grain by-products, in order to maintain a healthy rumen and minimize if not even eliminate the risk of acidosis and laminitis. Bulls with good genetics for intake will often gain near if not equal to their maximum genetic potential on a well-balanced forage-and-concentrate diet.

However, in certain parts of the U.S., summer heat combined with humidity and lack of wind can make for uncomfortable conditions throughout the middle of the day, from late morning until early evening. This added external heat load discourages maximum consumption by the bulls and hurts performance. Anything the producer can do during the summer months to encourage feed consumption will enhance ADG without increasing the risk of acidosis and foot problems. In addition, if feeding conditions can be made more comfortable during midday, there may be a reduced risk that cattle will come to the bunk in the evening hours hungry after several hours of not eating because of heat.

Placing shade near or directly over the feed bunk area is one way that cattle—especially black-hided cattle—can be made more comfortable, resulting in increased feed intake and better ADG during the hottest summer conditions.

When constructing shade structures, there should be a minimum of 20 ft² of shaded area per animal in the pen; more shaded area is better to provide more shaded loafing space for cattle when they’re not eating. If the shaded area is on dirt, the shade should be oriented longitudinally north-and-south so that the shaded area moves west-to-east with the juxtaposition of the sun. This will allow the moisture in the shaded area to dry, preventing accumulation of mud in the shaded area. However, if the shaded area is strictly on the concrete feed bunk pad, this consideration is not critical.

Performance of developing bulls is a function of total daily nutrient intake. If we’ve done a good job of balancing the needs for energy, protein, vitamins, minerals, and good quality and quantity of forage, the only x-factor left in the equation is consumption of the diet. By enhancing the comfort of cattle during times of hot, humid weather, we may be able to enhance short-term rate of gain without risking the long-term health of the bulls.

“Ammoniation of Wheat Straw dramatically improves Feeding Value”

by Chris Reinhardt, feedlot specialist

Although it’s a strange time to discuss winter forage needs, it’s about the right time to be planning what to do with wheat straw left after wheat harvest. “Planning” here is the key word.

Sometimes, forage is cheap and abundant; other times, everything has value. Ingredients we never would considered as suitable for feeding some years are other times in high demand and bring a good price. But while we want to give every opportunity due consideration, we’ve got to be sure to know what the true nutritional value of a feedstuff is, as well as any potential for toxicity.

Wheat straw has traditionally been fed to beef cows and can provide energy to gestating cows if supplemented with protein; however, ammoniation of the straw can effectively improve its feed value. Lignin (the “glue” that holds the cells together and gives strength to the stalk) normally prevents ruminal microbes from breaking down much of the cellulose in mature forages. Ammoniation breaks down the bonds between lignin and the cellulose and hemicellulose, allowing access for rumen microbes, and releasing energy for the cow to use.

Ammoniation not only adds nitrogen and increases the crude protein content of the forage, but also improves digestibility and consumption of the forage as well. Simply put, untreated wheat straw has very little energy and protein; whereas ammoniated wheat straw has protein and energy values similar to moderate quality prairie hay.

The ammoniation process is relatively simple and inexpensive. Stack the straw bales in either a 3-2 or 3-2-1 pyramid. Leave several inches between adjacent bales to allow ammonia to flow freely between the bales within the stack. Cover the stack with a single sheet of 6 mil plastic and completely seal the plastic around the base of the stack with soil. Any holes in the plastic should be sealed with tape.

Insert a hose from the anhydrous ammonia nurse tank under the plastic at the base of the stack at the midway point of the stack and seal the plastic around the hose. A manifold can be used to disperse the ammonia more evenly throughout the bale stack.

Most literature sources recommend applying anhydrous ammonia at the rate of 3% of the bales’ dry weight; however, recent K-State data suggests that 1.5% may be nearly as efficacious but has roughly half the cost. At a 3% addition rate, 60 lbs of anhydrous ammonia will be added for each ton of hay. For simplicity, a nurse tank can be used containing the exact amount of anhydrous ammonia for the amount of hay in the stack, and the tank can be allowed to empty completely. Apply the ammonia slowly to prevent rapid expansion and breaking of the plastic.

WARNING: Anhydrous ammonia is very toxic to the skin, eyes, and respiratory tract. Therefore, only conduct ammoniation in an open, well-ventilated area, always work upwind from the ammonia source, and always wear goggles and rubber gloves when exposed to the anhydrous ammonia. Have abundant clean water available in the event of exposure of the eyes or skin to the anhydrous ammonia.

The time required for the chemical breakdown to occur depends on ambient temperature: allow 1-2 weeks to cure if daily temperatures are in the 80’s or 90’s; increase this time to 4-6 weeks if ammoniating during the winter. Prior to feeding, remove the plastic and allow the bales to aerate for several days to allow excess ammonia to escape. Corn stalks can also be successfully ammoniated and forage quality effectively improved in a similar manner.

The value of wheat straw and corn stalks can be dramatically improved by ammoniation. The cost of ammoniation is presently $20-40 per ton of forage, depending on application rates, which makes the ammoniated crop residue a very cost-effective alternative to prairie hay which might need to be purchased and hauled from a distance. In the present market, all forage has some value; however, it’s imperative to test all forages to determine what that value is.

“A Cowboy’s Guide to the VFD”

by Chris Reinhardt, feedlot specialist

The veterinary feed directive (VFD) is essentially a prescription, written by your veterinarian, to your feed supplier, authorizing the supplier to sell you a medicated feed, and authorizing you to use an antibiotic in your feed, for some label-approved purpose. This will create some change in how we do business, and there will be some challenges. But to best prepare for those challenges, there are three key elements ranchers and cattle feeders should consider sooner, rather than later.

The first issue is that the veterinarian cannot write the VFD unless the veterinarian has a valid veterinarian-client-patient-relationship, or VCPR. The veterinarian has to have intimate knowledge of you, your operation, and your livestock, in order to be authorized to write the VFD. The basis for this VCPR will be determined independently by the veterinary governing body in each state, but a veterinarian friend of mine, Dr. Dave Rethorst of the K-State Veterinary Diagnostic Lab puts it simply: “If the vet can find your ranch, in the dark, at two in the morning to attend to a calvy heifer, you’ve probably got a valid VCPR.”

The second issue is that the VFD is a written document. A digital version can be transmitted to the feed supplier initially, but a written version must follow shortly thereafter. The point is two-fold: (1) because the VFD is written and signed by your veterinarian, use of the medicated feed cannot be approved by a phone call. You had better give your veterinarian time to get the documents submitted prior to your need for the medicated feed. (2) The VFD is submitted to the feed supplier, with a copy going to the producer, and a third copy remaining with the veterinarian. This is certainly an additional layer of management which hasn’t been required before. But for all parties to demonstrate that the sale and the use of the product was legal, the paper trail must be in place throughout the system.

The third issue is simply that the label-approved uses of the medications will not change with implementation of the VFD. Put another way, producers will still be able to use the drugs in the manner for which they have already been approved. However, some unapproved uses of certain products will most likely stop or be greatly curtailed, because a veterinarian must sign a document stating the intended purpose of the medicated feed, having prior knowledge of the need and the use.

The VFD won’t change the ranching world a great deal, but it will require some additional planning and subsequent record keeping. And if you don’t currently have a veterinarian involved in your operation, you’ll need to choose to either get a vet involved in your operation now, or lose the ability to buy certain medicated feeds in the future.

“A Pinch of Salt”

by Chris Reinhardt, feedlot specialist

For ranchers who live in areas where grass tetany is common, the fear of suddenly losing a good cow and prevention planning is a normal part of the ranching calendar.

Grass tetany, often referred to as “grass staggers”, causes cows to become highly agitated, develop a staggering gait, collapse, convulse, and, ultimately, die. Grass tetany is caused by insufficient magnesium in the blood stream. This deficiency is normally caused by a combination of low magnesium in forages coupled with elevated potassium in forages. The elevated potassium hinders absorption of magnesium in the animal.

This combination of nutritional circumstances occurs most commonly in the spring of the year, while cows (most often lactating) are grazing cool-season pastures, when abundant moisture and warm temperatures result in rapid, lush, growth of pasture grasses. Grass tetany is most commonly observed in cows grazing cool-season forages in the spring of the year; however, it also has been reported in cows grazing small grain pastures. It can also happen during the fall and winter months if there is a magnesium deficiency or excessive potassium.

Fortunately, if caught during the early stages, grass tetany can be successfully treated. Unfortunately, however, we often do not observe the symptoms until it is too late. Therefore, knowledge is power, and we know when cows are most likely at risk and can prepare our herd for this potentially deadly issue.

The most common grass tetany prevention practice is to provide cows with a free-choice mineral mix with an elevated level of magnesium (8-12% is commonly recommended), starting 2-3 weeks prior to the lush growing season. However, the elevated magnesium, along with the lush grazing conditions, often results in poor palatability and limited intake of high-magnesium mineral mixes. Therefore, producers should encourage consumption by placing mineral feeders near water sources.

In addition, because magnesium absorption by the animal is actually dependent on the animal having adequate available sodium, it is essential that cows have access to free-choice loose salt during this same time frame. Place salt near water sources to encourage consumption, and to ensure that abundant good, clean water is available in conjunction with the elevated salt intake.

For best results, provide a high-magnesium free-choice mineral, in conjunction with a separate source of loose, free-choice salt, both placed near a quality, abundant water source, shortly before and during any periods of lush grass growth, particularly if cows are grazing predominantly cool-season forages.

“Feeding Cows to Maintain Body Condition Score”

 by Chris Reinhardt, feedlot specialist

 The “optimum” or “target” body condition score for beef cows, at the time of calving, is a Body Condition Score (BCS) of 5 on a 9-point scale. BCS of 1-3 and 7-9 are rarely seen in most herds. A “5”, or moderate body condition, is typically considered an ideal target BCS at the time of calving. A BCS 5 shows no obvious fat deposits, but shows full expression of muscle through the round and shoulder, and has only 2-3 ribs obviously visible prior to morning feeding.

The reason this level of body condition is important to lifetime productivity is that energy is the first limiting nutrient when the cow’s biological systems are trying to determine whether there are sufficient nutrients available after calving to: (1) maintain her own body, (2) provide milk for the calf, and (3) begin to cycle prior to the breeding season.

A BCS “4” typically has no obvious fat deposition anywhere on her body, has less than complete muscle deposition in the round and shoulder, and clearly has 4-5 ribs showing prior to morning feeding. A cow in BCS “4” will typically delay cyclicity and may breed late in the breeding season. Unfortunately, if a thin cow calves late in the calving season she may miss the breeding season entirely. This is possibly the primary cause of infertility in the beef herd.

A BCS “6” is what most producers would consider a slightly “fleshy” cow. This cow has small but obvious fat deposits around the tail head, in the brisket, and in her flanks. She will have sufficient fat cover over the round and shoulder so that separate muscle groups are not clearly defined. The reason a cow is a BCS “6” at the end of the grazing season would be an “easy keeper”. But a cow that maintains a BCS “6” throughout the winter feeding season is probably a boss cow and is probably eating more than her given allotment of supplemental energy and protein every day.

Young cows often do not winter well for a number of reasons. Two-year-olds are still growing so some of the nutrient intake is going to growth of frame and muscle, in addition to maintenance. Also, they do not have the size, strength, or social status to out-compete older cows for feed and may be pushed out of the supplement line or the feeding area. Older cows may come out of the grazing season in poor body condition, and may lack the strength to compete in the feeding area. For these reasons, it is often recommended to find a way to separate thinner and younger cows from fleshier older cows to provide the thinner cows with additional supplemental feed.

Some producers worry about creating “welfare cows” who chronically require additional feed resources during the winter to simply stay up with their herd mates. Although this is logical, good record-keeping will help you to identify those individuals who simply cannot complete a production cycle without this “welfare”. Use good records to get one more calf out of her, then move her out of the herd. Simply allowing cows to fall out of the herd because of malnutrition cheats you out of several months of feed, and forces you to sell an open female rather than a bred female or a pair.

Finally, be prepared for the next storm or cold snap because cows can drop in body condition very quickly if we’re not prepared or vigilant. For 1,300 lb cows with a good, dry, winter hair coat, the thermoneutral zone is about 30-32°F. That’s the wind chill temperature, not simply air temperature. For every 10°F that the effective temperature (wind chill) drops below 32°, the cow’s energy needs increase by 10%. So if the effective temperature drops from 30° to 10°, we’ll need to supply an additional 5 lbs of hay. If temperature drops from 30° to 10° below zero, we need to supply an additional 10 lbs of hay. But there’s a limit to how much hay even a big cow can pack away. So be prepared to increase the supplemental feed proportionally.

Keep an eye on slipping body condition, on the weather forecast, and on the thermometer, and you’ll be able to fend off most anything Mother Nature throws at you and your herd.

“Mud Season….Again”

 by Chris Reinhardt, feedlot specialist

 Consider the humble Box Blade.

As a feedlot nutritionist, you’d think my favorite piece of equipment or technology would be the steam-flaker, the feed mixer, the small-ingredient inclusion system. No. I love the box blade.

Why? Because the nutritionist owns performance. BRD belongs to someone else, but when closeouts are chronically below expectations, the nutritionist often takes the heat.

As we come into a wet winter, lots can become muddy, and mud has devastating impacts on performance.

Cattle need a (relatively) dry comfortable place to lie down. If excessive moisture has resulted in destruction of the mound, it’s time to run the box blade. Cattle that cannot rest do not perform.

Cattle should have 20-25 square feet of mound area on which to lie down. The top surface (5-10 feet wide) of the mound should be crowned side-to-side, and longitudinally the mound should also have a mild grade similar to the direction of the general slope of the pen, which is normally between 1 and 6%. The sides of the mound should have a slope of 1:5 to enhance drainage yet still allow cattle to lie on the surface.

The end of the mound should connect directly to the concrete bunk pad so that, especially during muddy conditions, cattle can move freely and easily between the mound and the bunk and water areas. This will encourage both feed consumption and resting behavior, both of which will enhance performance during and after inclement weather.

“High Risk Calf Nutrition”

 by Chris Reinhardt, feedlot specialist

 What are the three most critical required “nutrients” for high-risk calves who have been on a truck for an extended period? Hay, water, and rest. Alright, those aren’t all exactly “nutrients” per se, but they are definitely REQUIRED. Nutritionists, veterinarians, and feedyard managers could probably argue for a month as to which of the three is the most important and urgent; none the less, they all are both important and urgent.

The rumen thrives on constancy. The animal is designed to keep a steady supply of forage and water flowing to the rumen, a steady amount of waste products flowing out from the rumen, and a steady stream of nutrients from fermentation absorbed through the rumen wall. Cattle that have been off feed and water for a number of hours need to re-start this flow.

Good quality grass or cereal grain hay, long-stemmed, needs to be available for calves to nibble on, along the bunk line and also in a hay feeder. Normally we want to encourage calves to get all their feed from the feed bunk but extremely stressed calves need to feed immediately and there may not be sufficient linear space at the bunk for all calves to eat at once. There needs to be a safe place for small or timid calves to eat hay in peace.

Clean, fresh water needs to be available. A separate additional water tank should be placed along the fence line so that (a) there is room for many calves to water immediately after arrival and (b) there is plenty of water for all the calves. These tanks may need to be re-filled throughout the day depending on demand.

Exhausted calves will want to lay down immediately after arrival. Opinions vary with respect to the urgency of rest. Some experts believe that immediately upon entry to the receiving pen exhausted calves should be gently moved to the feeding and drinking areas, to encourage them to eat and drink prior to bedding down; others contend that 30 minutes of rest prior to feeding and drinking is valuable. Most agree that after feeding and drinking, calves should be allowed an extended rest period prior to post-arrival processing. Some suggest an hour of rest for every hour on the truck. This is a rough guideline.

If pen conditions are wet upon arrival, straw or corn stalks should be put out, on the mounds, to give calves a relatively, dry, clean place to bed down. Regardless, receiving pens should have abundant area per animal, bedding during wet conditions, and shade during hot conditions.

We often place unrealistic expectations on vaccines and antibiotics to prevent disease in high-risk calves. It might be better to focus on these three important “nutrients” first.

“Weaning Nutrition”

 by Chris Reinhardt, feedlot specialist

 The biggest hurdle in getting calves started off right in the fall is the weather. The sooner you get calves through the stress of weaning and started on feed, the better. If calves get through the stressful process of weaning from their dam and onto feed ahead of fall rains or ice storms, they have a good chance at success.

Good quality grass hay is very palatable and it’s a good way to attract bawling calves to the bunk. Don’t use a bale ring; this teaches calves NOT to come to the bunk to eat and you’ll just need to re-train them to the bunk later. After 1-2 days of free choice feeding long stemmed loose hay in the bunk, limit hay consumption to about 1.0% of bodyweight (5 lb for 500 lb calf) and top-dress 3-5 lb/head (for 500 lb calf) of the weaning ration on top of the hay. As calves consume this small amount of mixed diet, begin to further reduce the amount of loose hay you feed each day and increase the amount of mixed diet.

A mixture of 50% ground hay (grass or grass/alfalfa mix), 50% concentrate (including cracked grain and a starter supplement) can be fairly easy to blend and manage. However, if by-product feeds such as wheat midds, soy hulls, distiller’s grains, or corn gluten feed are available and priced at or below the cost of grain on an equal dry matter basis, the by-products can be substituted for about half of the grain component. Silage should be limited to ≤10% in the starter ration but can be increased in later step-up diets.

CAUTION: Increase the feed offered per head very gradually. Excessive consumption of even a moderate energy starter diet can cause acidosis in a calf which hasn’t been fully adapted to grain. Increase the ration no more than 2 lbs/head every other day. If calves are hungry, feed 1-2 lbs of extra hay in the bunk. If stools become loose, you may have increased the amount of mixed ration too rapidly. If this happens, feed an additional 1-2 lbs/head of hay. Healthy calves should consume about 3% of bodyweight by 14 days on feed. Sick calves may take longer to reach this level of consumption. Gauge any changes you make to feed deliveries on cattle behavior and disease status—slower may be better in the long run.

You want to make the weaning diet as easy of transition for the calves as possible. The diet you feed needs to deliver energy, protein, vitamins, and minerals, all in a form that the calves will readily consume.

Avoid the temptation to skimp on QUALITY of starter ingredients; also, avoid the temptation to rush the QUANTITY of starter ration you provide for the calves to eat. When calves have consumed 3% of their body weight of the starter ration continuously for 3-5 days, you can move them up to the next step-up ration.

“It’s Time to Precondition”

 by Chris Reinhardt, feedlot specialist

Vaccine and antimicrobial technology continues to improve at a breakneck pace. Yet we continue to see that calves which are unprepared for life in the feedlot and which undergo significant stress during and after weaning in route to the feedlot will have morbidity upwards of 30% and first treatment success is often 30-50%. Calves which get mild respiratory disease will gain 0.2-0.4 lbs less ADG and those calves requiring multiple treatments will gain 0.6 lbs less for the entire feeding period. This translates to about 15 lb less carcass weight and 10-15% fewer choice carcasses. It pays to keep calves healthy.

Preconditioning can mean everything from giving calves a vaccination prior to weaning, all the way to 2 rounds of vaccination, pre- and post-weaning, weaning from their dams for 45 to 60 days, and transitioned onto a total mixed ration, feedbunks, and waterers.

As far as animal performance is concerned, the extent of preconditioning needed to minimize post-arrival problems and maximize feedlot performance depends on the extent of stress imposed on the calf during transition.

Recent studies here at K-State suggest that single-source calves shipped 4 hours to a feedlot will benefit from pre-weaning vaccination and weaning and feeding for at least 2 weeks pre-shipment. If calves are going to be shipped a great deal farther, will be extensively commingled either in transit or upon arrival, and may experience adverse weather conditions post-arrival, vaccination and weaning for 6-8 weeks pre-shipment would be preferred.

Investing time, technology, and labor into the calf crop has very real costs for the rancher. But the high purchase price of weaned calves entering the feedlot means the risk of respiratory disease and the financial uncertainty that respiratory disease causes for feedlot producers is at historically high levels as well. Many feedlot producers are willing to pay ranchers a premium to mitigate some of this disease risk which causes them economic uncertainty—consider it “biological risk management.” When certified preconditioned calves are sold at special preconditioned calf sales, they have the potential to bring unprecedented premiums compared to non-preconditioned, “commodity” calves.

Respiratory disease is the most costly disease in the cattle industry, and the greatest factor affecting calf performance in the feedlot. If you can prevent or control disease, you can, to a certain extent, control performance of calves. Feedlots are paying premiums for calves which are prepared for life at the feedlot. Why? Because they perform. As a rancher, you can and should get paid for your investments of time, money, and management.