Here Comes Pneumonia Season

Veterinarian Carrie Bargren of River Valley Veterinary Clinic, Plain, Wis., said a calf that experiences pneumonia at less than 3 months of age will be affected well into her lactating career. Bargren shares a list of strategies on which she advises clients to prevent pneumonia in growing replacements. ( Farm Journal )

The calfhood disease with the longest-lasting impact on lifetime performance is – hands down – pneumonia, according to Carrie Bargren, practicing dairy veterinarian at River Valley Veterinary Clinic, Plain, Wis.

“A calf that has had pneumonia, even if she has recovered with treatment, will be 2.4 times more likely to have impaired growth in the first 6 months of life,” said Bargren. “She also will be 2.4 times more likely to die between the ages of 3 months and 2.5 years, and there is the same risk that she will calve 2 months later than her healthy herdmates.”

Bargren explained there are three categories of pneumonia in calves:

  • Aspiration – This form of pneumonia occurs when any solid material is inhaled and enters the lungs. The most common cause is improper use of esophageal feeders when administering colostrum. Aspiration also may occur during a difficult birth when a calf inhales some meconium (first manure) or amniotic fluid. A common source of aspiration in older calves is nipples with holes that are too large, which allow calves to consume milk too quickly.
  • Bacterial – The three primary organisms that cause bacterial pneumonia in calves are Pasteurella multocida, Mannheimia hemolytica, and Mycoplasma species. “Bacterial infections that occur in the first few days of life result from infection within the dam, aspiration or contaminated colostrum,” said Bargren. “As calves grow older, new infections typically are acquired from the environment or other sick calves.”
  • Viral – BRSV, IBR, PI3 and BVDV all can instigate pneumonia in calves. “A viral pneumonia then predisposes calves to acquiring bacterial pneumonia,” said Bargren.

Bargren advises her clients to take the following measures to prevent pneumonia in young calves:

  1. Vaccination – Dry cows can be vaccinated for virtually all of the viral pathogens that cause pneumonia, and the antibodies for them then can be transferred to calves via colostrum. In addition, she said, “a good intranasal vaccine at birth will stimulate the tissues in the airways to make antibodies and be ready to kill respiratory pathogens before they enter the body, providing additional protection for the calf for 4-6 weeks.” She suggests a booster of intranasal vaccine at weaning.
  2. Colostrum delivery – Colostrum is the only immune protection calves have for the first few weeks of life. Bargren recommends feeding 4 quarts within 6 hours after birth, and monitoring colostrum quality with a refractometer. Checking calves for total proteins (TP) to screen for Failure of Passive Transfer (FPT) of immunity is advised to monitor colostrum management.
  3. Housing – “Clean air and deep bedding are the most important factors in preventing disease through housing management,” said Bargren. “Proper ventilation systems in calf barns will bring in clean air and remove contaminated air.” She recommends at least 26 square feet of resting space for calves in hutches or individual pens, and at least 30 square feet per head in group pens. Regardless of type, she said shelter systems should protect calves from extreme heat, cold, wind chill, rain, dust and aerosolized pathogens, all of which can stress immunity.
  4. Nutrition – “Proper nutrition is required for healthy growth rates and to sustain immune function,” said Bargren. “Adjust volume to accommodate for cold temperatures.”

Bargren noted a routine screening program is necessary to detect pneumonia in young calves, especially because their early clinical signs usually are very subtle. “An ideal time to watch for respiratory disease is feeding time,” she suggested. “A newly sick calf will be slower to drink or too uncomfortable to lie down afterward.”

To improve respiratory disease detection and monitor treatment efficacy, Bargren recommends using the Calf Health Scorer app from the University of Wisconsin School of Veterinary Medicine.

Potentials for Plant and Other Toxicities in Cattle

While Johnsongrass is a good quality forage, it can be challenging to control in pastures where the perennial, warm-season grass is not desired. Prussic acid production under stress can pose a risk to livestock when grazing Johnsongrass, especially during prolonged droughts or after a frost.
( Dirk Philipp, University of Arkansas )

Fortunately, there has been plenty of rain this year. However, heading into late summer and fall are times of the year to watch out for plant toxicity in cattle.  In some cases, plants can become more toxic during drought and heat stress.  In addition, there is the increased potential for cattle to ingest toxic plants due to lack of other feedstuffs.  There may also be more access to toxic plants.  With droughts come increased weed infestation of pastures, hay and crop fields.   Penned cattle may also be in corrals or drawn to low lying areas that are still green, both of which are where toxic plants are likely to grow.  Differentiating “good” vs. “bad” plants is a learned behavior, so toxicity is more likely in young animals and animals moved to a new location.  A grazing management and supplemental feeding plan is essential to minimize problems.  Veterinarians and producers should be familiar with which plants can cause problems in their area, and try to avoid them.  The following discussion covers some of the plants and situations to watch for during drought situations.  There may be plants that grow some regions that are not covered.

Stressed plants more readily accumulate nitrates and prussic acid (cyanide).  Drought stress can cause both pasture forages and weeds to accumulate toxic amounts of nitrates.  Recently fertilized pastures are also at higher risk.  Plants that have accumulated nitrates remain toxic after baling or ensiling.  Test forages for nitrates to prevent poisoning.  Prussic acid accumulates most often in sorghums, sudans and Johnsongrasses, but these plants can accumulate nitrates also.  There is no test for prussic acid, but it dissipates when plants are baled or ensiled, so harvested forages are safe.  Cattle poisoned by nitrates or prussic acid are usually found dead, so prevention of these toxicities is critical.   Cattle with nitrate toxicity have methemoglobinemia (brown blood) and cattle with prussic acid toxicity have cyanohemoglobinemia (bright, cherry red blood).  Nitrate and prussic acid both interfere with oxygen carrying capacity in the blood, so pregnant cattle surviving these poisonings often abort.

Two of the most toxic plants found in croplands and pastures are coffeeweed and sickle pod.  Cattle will generally not graze the green plant unless other forages are scarce.  However, they will readily eat the seedpods that are dry after a frost.  The plant remains toxic when harvested in hay/balage/silage.   Coffeeweed and sicklepod are toxic to muscles and cause weakness, diarrhea, dark urine, and inability to rise.  There is no specific treatment or antidote, and once animals are down, they rarely recover.

Pigweed or carelessweed is very common in areas where cattle congregate.  Cattle will readily eat the young plants, but avoid the older plants unless forced to eat them.  A common pigweed poisoning is when cattle are penned where pigweed is the predominant plant and no alternative hay or feed is provided.  Red root pigweed is more toxic than spiny root pigweed, but is less common.  Pigweed can accumulate nitrates, so sudden death is the most common outcome.  It also contains oxalates, so renal failure can also occur.

Black nightshade is common in croplands, and like pigweed, in often in high traffic areas.   The green fruit is most toxic, so cattle should not have access to nightshade during this stage, and nightshade remains toxic in harvested forages.  Nightshade is toxic to the nervous and gastrointestinal systems, and causes weakness, depression, diarrhea, and muscle trembling among other signs.  Bullnettle and horsenettle are in the same plant family as nightshade.  They are also toxic, although less so, and are usually avoided by livestock unless other forages are not available.

Blue-green algae blooms in ponds can also occur in hot weather.  They are most common in ponds with high organic matter, such as ponds where cattle are allowed to wade, or where fertilizer runoff occurs.  The blue-green algae accumulates along pond edges, especially in windy conditions, and exposes cattle when they drink.  Both the live and dead algae are toxic.  The toxins can affect the neurologic system causing convulsions and death, sometimes right next to the source.  They can also affect the liver, causing a delayed syndrome of weight loss, and photosensitization (skin peeling in sparsely haired or white haired areas).

Perilla mint causes acute bovine pulmonary edema and emphysema (ABPE), usually in late summer.  It grows in most of the central and eastern United States and is common in partial shade in sparsely wooded areas, and around barns and corrals.   There is no treatment, so prevention is critical.

Cattle with access to wooded areas may eat bracken fern.  Cattle must eat roughly their body weight over time before toxicity occurs, but may do this in situations where other forage is not available. Braken fern toxicosis causes aplastic anemia.  Fever, anemia, hematuria, and secondary infections are some of the most common signs.

As summer moves into fall, the potential for acorn toxicosis increases.  Cattle have to eat large amounts usually to become sick, but those that are in poor body condition and hungry are more likely to do so.  Clinical signs include constipation or dark, foul-smelling diarrhea, dark nasal discharge, depression, weakness and weight loss.

The lack of summer forages and the need for supplemental feeding during a drought can increase the likelihood of feeding “accidents” and toxicities.  Producers may be tempted to feed cattle pruning’s of ornamental plants, many of which are highly toxic.  Grain overload is also a potential problem if access to concentrate feeds are not controlled.  Salt toxicity can occur if hungry cattle are allowed free access to high salt containing “hotmixes”.  Even though these are meant to limit intake, initial intake can be high enough to cause toxicity in starved or salt deprived cattle.  Feeding byproduct feeds, candy, bread, screenings, etc. may also be more common, all of which have the potential to cause problems.  Producers may also be tempted to feed moldy hay or feed, which can lead to toxicity problems.

With careful planning, plant toxicities can be avoided. If you have questions on toxic plants and how to identify/avoid them, please contact your local veterinarian or Extension agent. If you have further questions please feel free to contact me at, lstrick5@utk.edu, or 865-974-3538.

Moisture the Critical Component to Good Silage

One of the most important steps to make good silage is to cut it at the proper moisture level. The optimum moisture range for cutting corn and making silage is between 60-70% moisture (30-40% dry matter). Given the genetics of today’s corn varieties, utilization of the old relationship between the milk line and plant moisture content may not always be accurate.

An easy, quick and relatively inexpensive method to determine the actual moisture content of the whole corn plant is using a microwave oven. One additional advantage is that it takes typically less than 20 minutes to run the test.

So what equipment will you need to facilitate the moisture test?

  • Microwave, with a turntable (preferably). Your wife or significant other will appreciate you NOT using the kitchen microwave or doing this in the house kitchen, as it does produce an unpleasant odor. It is thus recommend to have a microwave in the shop or barn to run the moisture test.
  • Scale, one that weighs in grams is best.
  • Container, something that is microwave safe such as paper plate, paper boat, or a glass or plastic dish.
  • Water – 8 oz glass to protect the microwave oven
  • Paper & Pencil to record weights
  • Calculator

Next you need to collect a sample. Collect at random 10-20 plants throughout the field. You will need to chop these plants and this can be done by either shredding them in a brush chopper/branch shredder or by running them through your chopper. Please keep in mind that this can be a very dangerous process and care should be taken when doing this. The other option is to chop test areas in your field. Then take random grab samples from the green chopped silage. You should have about 2 gallons worth of product to mix and collect your test sample from. Once you have collected a representative sample you can start the process to run the moisture test.

Follow these steps to determine the moisture content of your corn silage or forage. Please note that this method can also be used to determine moisture content in any other forage.

Microwave Moisture Testing of Forages

  1. Take your gram scale and weigh the container you will use to hold the sample. This weight is known as Value A.
  2. Mix your sample and place about 100 grams in the container. Collect the total weight of the container and wet sample, record the weight as Value B.
  3. Put an 8oz. glass of water in the corner of the oven.
  4. Put the container with the sample in the microwave oven. Using a medium to high heat setting start drying the sample, starting with approximately 3-4 minutes if you suspect the sample is above 35% moisture.
  5. Remove the container and sample, weigh them, and record the weight. It should weigh less than the Value B that you initially recorded.
  6. Gently stir the sample and place back in the microwave.
  7. Reheat the sample again for another 30 seconds. Remove, reweight, and record the weight. You should continue this process, recording the weight every time. (You will need to be careful not to char or burn the sample. If you do, then either start over or take the previous recorded weight prior to charring the sample. You do not want your sample to be charred, so a hint is to go in time increments of less than 30 seconds once you feel your sample is getting close to dry.)
  8. Once you have two continuous weights that are equal, the sample is considered dry. Record this final weight as Value C.

Lastly you will need to calculate the percent moisture using the following formula:

  • Value A = weight of container
  • Value B = weight of container + initial wet sample weight
  • Value C = weight of container + dry sample weight

%Moisture = B - C divided by B - A times 100

Producers need to remember that if the silage is too wet there is a risk of butyric acid forming and nutrients being lost due to seepage. Silage that is over 70% moisture should not be harvested and should stand in the field for a few more days. On the other hand if it is too dry it will not ferment or pack adequately resulting in mold development. You may then need to add water to get an adequate pack and fermentation process. Therefore, having an accurate determination of what your corn silage moisture is running is critical in putting up good silage in a timely manner.

Corn Silage Maturing Fast

Corn plants can lose more than two points of moisture on hot, windy days. ( Farm Journal, Inc. )

With plenty of moisture and lots of sunshine in much of the upper Midwest, corn silage is rapidly maturing.

Now is the time to aggressively monitor crop maturity and plant dry matter, says John Goeser, animal nutrition, research and innovation director for Rock River Laboratory in Watertown, Wis. Although ideal dry matter will vary with silage storage type, the general guideline is to shoot for 35% dry matter (65% moisture.

“The opportunity for failure, or for challenges to arise, is far greater when we aim for dryer and more mature thresholds,” says Goeser. “[Corn silage] will be harder to pack at those dryer levels. If we experience a dry spell with 80° F days and wind for a week, corn can go from drying out a point a day to losing several points of dry matter per day.”

That can lead to a “fluffier” crop with kernels harder to process, he says. “Realizing that chopping can take some time, it’s best to begin harvest just before you reach the dry-matter target,” he says. “Continue chopping beyond the target and realize an average dry matter this is right around the ideal level.”

Goeser also recommends:

Consider high cutting. “Many areas experienced plenty of heat and moisture early in the growing season this year, so I’m forecasting fiber digestibility and stover characteristics to be more ‘woody’ this years,” says Goeser. “These characteristics can be varied with cutting height.”

He recommends a simple on-farm experiment when kernels reach the half-milk line. Cut three or four stalks at normal height, another set of stalks at 12 to 14” and a third set at 18 to 20”. Chop these stalks and then submit the samples for neutral detergent fiber digestibility analysis. The results should tell you which cutting height will provide optimal feed.

Utilize kernel processing scores (KPS) throughout harvest. “It’s one thing to have your equipment ready for the season, but changes happen in equipment and crop status which affects KPS,” he says. So monitor KPS daily or every couple of days.

“Understand that the KPS benchmark is lower for unfermented, fresh chop whole plant corn relative to what it will be six months into fermentation,” he says. The fresh chopped corn KPS goal is 60 to 65, while fermented corn silage should be 75 or better, he says.

Use free app to monitor crop conditions in your area. Rock River Lab is providing a free, crowd-sourced phone app called InField Updates that reports dry matter, NDF and starch statistics on a map. This data can be used to track crop progress in your area. Download the FeedScan app and click on “InField Updates” to try out this tool.

Time to Plan for Corn Silage Harvest

( Sponsored Content )

Now is the time to start thinking about and planning for corn silage harvest. Preparations taken now and close attention to details like moisture content can mean higher-quality silage when you peel back the plastic months from now.

One of the most important factors influencing corn silage quality is moisture content at time of harvest. Ideally, corn silage should be harvested at the moisture content appropriate for the type of silo used. Recommended moisture contents are 65-70 percent for horizontal silos, 63-68 percent for conventional tower silos, 55-60 percent for limited-oxygen silos and 65 percent for silo bags, writes Jud Heinrichs, professor of dairy science and Gregory W. Roth, Ph.D., professor of agronomy, both with Penn State.

Crop dry matter yields are maximized near 65 percent moisture (Table 3) and losses during feeding, storage and harvesting are minimized. Delaying harvest can reduce both the fiber and starch digestibility as the stover gets more lignified and the overmature kernels become harder and less digestible if left unbroken after ensiling.

Table 3. Corn silage yield and quality as influenced by growth stage.

Corn Silage

Silage moisture at harvest is not difficult to determine and should be monitored, if possible, to prevent harvesting of the crop outside of the desired moisture range. A commercial forage moisture tester or a microwave oven can be used to determine the moisture content fairly rapidly. If silage moisture is above ideal levels, then harvest should be delayed if possible.

Corn that is ensiled extremely wet will ferment poorly and lose nutrients by seepage, which also has potential to damage the silo and if not contained, contaminate local water supplies. Silage that is too dry may result in poorly packed material, causing more mold and spoilage due to air trapped in the silage. In dry, overmature corn silage, the stover portion of the plant is less digestible and contains lower amounts of sugars and vitamin A.

Moisture content cannot be determined accurately using the kernel milkline, because of variations due to weather and hybrids. Moisture content should be measured rather than estimated.

One strategy for timing corn silage harvest is to chop a sample at the full dent stage, just as the milkline appears, and determine the moisture content. Then estimate the harvest date by using a typical drydown rate of 0.50 to 0.75 percentage units per day.

Harvest considerations should also focus on obtaining the correct particle size distribution and the need to process the crop. Processing silage refers to putting the chopped material between two rollers that are installed in the harvester to crush the harvested material as it passes through. Kernel processing units are becoming more popular on corn silage harvesters in Pennsylvania. Kernel processing has the advantage of crushing cob slices and kernels and can increase the starch availability by about 10 percent in the silage. The current data shows no clear nutritional advantage to processing silage unless it is overly mature with hard kernels. In some cases, this has resulted in increased milk production compared to unprocessed silage. A good general recommendation for the theoretical length of cut for processed silage is 3/4 inch with a 1-2 mm roller clearance.

Kennel Processing

Figure 1. The Penn State Particle Size Separator can be used to monitor silage particle size.

Corn DistributionFor unprocessed silage, an average theoretical length of cut should range from 3/8 to 3/4 of an inch. Particle size of corn silage should be monitored during harvesting because it can change as crop moisture content varies. The Penn State Particle Size Separator can be used to estimate the particle size distributions for harvested corn silage.

Table 4. General recommendations for corn silage particle size distributions on the three sieves and bottom pan in the Penn State Particle Size Separator.

Once harvesting has begun, fill the silo as rapidly as possible and continue until it is filled. Continue to evaluate processed corn throughout the harvest season. Kernels should be broken into multiple pieces and cobs should be broken into thumbnail-sized pieces or less. As the crop matures after half milkline, it may be desirable to have more kernel breakage so that much of the grain is in the bottom pan of the particle size separator.

The most desirable method of packing bunker silos is the progressive wedge method, where silage is continually packed on a 30-40 percent grade. This minimizes the surface area exposed to the air that can result in DM and forage quality losses. If this is not possible, the silos should be packed by spreading relatively thin layers of silage (6 inches deep) and packing it well. If packed well, the density of the silage should be about 14 pounds of dry matter per cubic foot.

Bunker Silos

Figure 2. Technique for ensiling forage in bunker silos.

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Sponsored by Lallemand Animal Nutrition

Benefit from creep feed

Dan Herold, Ph.D., Manager, Beef Nutrition And Technical Services, Hubbard Feeds

The benefits of creep feeding can reach well beyond weaning weight. ( Hubbard Feeds )

Cow-calf producers often simply view creep feeding as a way to increase calf weaning weights beyond what can be produced with mother’s milk and available forage. However, the benefits of creep feeding can reach well beyond weaning weight and are summarized below:

Pre-weaning

  • Additional protein, vitamins and trace minerals enhance immunity and performance.
  • Higher energy intake at an early age can increase marbling and carcass quality grade.
  • In early weaning programs, young calves are prepared to start on feed more quickly.
  • When fence-line weaning, feeders serve as a nutrition base station to nourish calves.
  • Coccidiosis control can be provided in creep feed to promote health and weight gain.

Post-weaning

  • There is a more immediate transition to bunk feeding with less weaning shrink.
  • Early feed intake reduces weaning stress and improves health and weight gain.
  • Better nutrient status supports the immune system and vaccine response.
  • Heavier calf-feds can be first to market in spring and summer, saving feed and yardage costs.
  • Setting the stage for success

A successful creep feeding program requires an understanding of factors affecting feed intake. Feed quality and quantity determine energy intake of young calves and is based on the nutritional theory that calves will select the most nutritious and easily digestible diet available. The ration choice for nursing calves follows this order of preference: milk > fresh, young grass > creep feed, or mid-bloom grass > mature grass.

When milk production and grass quality decline late in the season, intake will shift from forage to creep feed. Moderate-energy creep is now the most nutritious option to fill the calves’ hunger gap and fuel their increasing energy needs for growth. Creep feeding late-season requires more attention and management than was required in early to mid-summer. Calves’ appetites are growing at a time when their base ration of milk and grass are quickly disappearing.

A rapid increase in creep feed intake can catch cow/calf producers by surprise. In a typical 100-day feeding program, creep feed consumption averages 4.5 pounds per day. This is based on a range beginning at 0.5 pounds per day in early July and ending at 8 to 12 pounds in late October. It may require over a month for the feeder to empty early in the summer, and just days to empty it later in the fall. Consider that 50 calves eating 10 pounds of creep feed per day will consume 1 ton of feed in just four days. A sudden increase in intake is a good indication that the pasture is nearly spent and it is time to wean calves.

Creep is intended to supplement milk and grass, rather than to serve as a complete feed. It is natural for hungry calves to increase creep consumption when faced with declining milk and forage supplies. However, the sudden increase in energy intake can trigger an undesirable response from rumen bacteria. Rumen “bugs” that are accustomed to slowly fermented grass will break down creep feed at a faster rate. For calves, the shift from slowly digested forage fiber to an abundance of readily available energy in the rumen usually yields the same outcome: enhanced fermentation rate, increased ruminal acid and gas production, and potential digestive upset. This sequence of events is why it is strongly recommended to wean at the appropriate time and never run out of creep feed. This rule applies especially at the end of the grazing season, when intakes are highest. The risk of overeating is at its peak when the feeder is refilled, and hungry calves return to make up for lost meals.

As calves become more dependent on creep to meet the demands for maintenance and growth, more attention needs to be given to maintaining feeders:

  • Gates should be adjusted to encourage calves to work a little harder to obtain creep. Inserting the handles of a standard set of pliers between the feed gate and bottom of the feeder can serve to gauge the correct distance.
  • Keeping the opening to just a few inches will keep feed flowing while reducing accumulation of fines and spoiled feed. Excess feed accumulating in the trough absorbs saliva as calves nuzzle and sort feed to locate larger particles. The result is soft pellets that break down into fines, which can build up quickly. This accumulation encourages more sorting, as calves don’t like fines, and the cycle continues until the feeder is cleaned and fresh feed is available.
  • Feeder troughs should be checked and cleaned out routinely and at greater frequency as the season progresses.

As previously noted, creep feed can provide several benefits by supporting weaning weight, calf health, ease of weaning and, ultimately, quality and value of the finished product. However, the objective of the program should be to achieve a balanced intake, with creep feed serving to supplement milk and grass rather than replace it. When properly used, creep can take pressure off both the cow and forage resource pre-weaning and help calves transition through post-weaning stress. When creep feed intake rapidly ramps up late-season, it is a clear signal that it is time to wean. Digestive upsets are the result of failing to recognize this transition. Use proper management to prevent sudden swings in energy consumption.

Using creep feed as a strategy to extend the grazing season past the point of optimum intake is an unnecessary risk to calf health and producer profit. Creep feeding coupled with good management will yield the most benefits both pre- and post-weaning.

To bloom or not to bloom?

By Kassidy Buse

A common recommendation of agronomists is to let one alfalfa cutting reach bloom each year.

Ev Thomas, retired agronomist from the Miner Research Institute in Chazy, N.Y., says otherwise in The William H Miner Agricultural Research Institute Farm Report.

“For many years, I’ve said that in managing alfalfa for dairy cows, you should never see an alfalfa blossom, from seeding to plowdown,” says Thomas.

Thomas also notes there’s room for difference of opinion due to no research supporting either opinion.

But, if one cutting is to bloom, which cutting should it be?

The first cut of alfalfa-grass typically contains the most grass. Grass, even the late-maturing species, is close to heading when alfalfa is in the late bud stage.

The second cut is exposed to long, hot June days that result in highly lignified, fine stems. A Miner Institute trial found that the stem quality of bud-stage second-cut alfalfa was no better than full-bloom first-cut alfalfa.

The third cut can be influenced by prior harvest management. If it was a late second cutting, the third cut was growing during midsummer heat. This cut would also have highly lignified stems.

The fourth cut often takes a long time to bloom, if it makes it there. A killing frost might arrive first.

For any cutting, the more grass in the stand, the lower the forage quality if alfalfa is left to bloom.

“The objective of letting alfalfa bloom is to improve root reserves, and therefore extend stand life,” says Thomas. “We need to balance the impact of delayed harvest on plant health with the economics of feeding alfalfa of lower quality that is needed by today’s high-producing dairy cows,” Thomas adds.

How alfalfa and alfalfa-grass is managed depends on if the goal in mind is long stand life or high milk production potential.

Digital Dermatitis Isn’t Just a Dairy Herd Problem

Digital Dermatitis Isn’t Just a Dairy Herd Problem

Acute active digital dermatitis lesions can cause pain and lameness in cattle, which leads to declines in animal welfare and food production.
( Arturo Gomez Rivas, University of Wisconsin )

Digital dermatitis (DD), also known as hairy heel warts, was discovered in 1974 in Italy. The disease first popped up in US dairy herds in the 1980’s, and spread rapidly during the 1990’s as herds expanded. The co-mingling of multiple dairy herds into one barn or facility made a perfect scenario for DD to infect millions of cattle.

Digital dermatitis is an incurable disease. Once cattle are infected with DD, they have it for life. Digital dermatitis cannot be cured, only managed. Treponemes, a spiral-shaped bacteria, cause DD. Treponemes that cause DD enter the body of an animal through a break in the skin on the foot. Treponemes hate oxygen and thrive in pen environments with poor hygiene, wet floor surfaces, and overcrowding. When cattle are subjected to standing in mud or manure for prolonged amounts of time, softening of the skin occurs and allows treponemes to penetrate the skin.

Digital dermatitis lesions mainly occur on the back feet. Lesions can spread between the toes and sometimes appear on the front of the foot. Lesions are recognized by two different appearances. One type of lesion, hyperkeratotic, appears as a raised callous. Proliferative lesions appear to have long fibrous hairs. Active DD lesions may appear initially as a raw, red, oval ulcer on the back of the heel just above or at the coronary band. There are six stages of DD. Named after one of the researchers who discovered DD, (Mortellaro), “M” stages are categorized as M0 (no lesion, healthy foot), M1 beginning of a lesion, M2 active, M3 healing, M4 nonactive healed lesion, and M4.1 nonactive healed lesion with an active M2 on top of a healed lesion.

Beef herds are not immune to DD. While DD is present in beef cow/calf herds, feedlot cattle are especially susceptible. The key to controlling DD is to prevent outbreaks and spread of the disease. Once you find it, you are too late, your herd is infected. Cattle who are co-mingled with other groups of cattle, transition cattle, and animals under stress are at highest risk of contracting the disease. Untreated DD can cause lameness resulting in decreased rate of gain in feedlot animals, and reduced fertility and milk production in replacement cows. In addition, losses incurred through treatment costs, increased labor, and potential animal mortality are economically detrimental to the overall enterprise.

Digital dermatitis causing treponemes are spread through manure and mud. Keeping pens clean and dry as possible is a good start to prevent the spread of disease. Prompt treatment of active M2 lesions will reduce the spread of DD to other cattle and reduce the chance of the infected animal’s development of lameness. Treatment requires the lifting of the foot, cleaning of the lesion, and applying topical oxytetracyclin. Dr. Dörte Döpfer from the University of Wisconsin School of Veterinary Medicine recommends <2g of oxytetracyclin per treatment. M4 lesions are a reservoir for future outbreaks. Treponemes lie deep within the skin and can become active at any point. Running cattle through a footbath two to three times per week should keep the lesion in the chronic nonactive M4 stage. Depending on preference, a premix, formalin, or copper sulfate solution will serve as an antibacterial and hoof hardening solution. All footbath solutions have pros and cons, you can read more about footbath options at: https://fyi.uwex.edu/dairy/resources/animal-well-being-herd-health/

Early detection and treatment are important factors to controlling DD in the beef herd. Walking pens to detect DD is the first step of control. Utilizing an integrated management strategy of footbath use, hoof care, and footbath use will help control the spread of the disease. Not every animal exhibits the same symptoms and reacts the same to treatment, so utilizing a consistent control strategy is important. It is still unclear how much DD economically impacts the beef industry, but one thing is for certain, DD is here to stay.

Hay Cost Calculator

Hay season is around the corner and many producers are likely greasing the wheels, sharpening blades, checking belt tension, and settling in for a long hay season. However, it may be wise to do some calculating and revisit some management decisions to determine hay needs and to see if there is a way to reduce hay needs. This could be important considering the tremendous cost of feeding cattle 365 days per year and knowing hay tends to be one of the most expensive feeds available.

In order to achieve the task of determining how much hay is needed and what the potential cost will be, Mr. Kevin Ferguson, Ms. Rebekah Norman, and Ms. Tammy McKinley developed an Excel based “Hay Calculator” to help with the calculations. That file can be found at https://ag.tennessee.edu/arec/Pages/decisionaidtools.aspx. The tool takes into account storage losses, feeding losses, bale size and weight, cattle weight, consumption, number of days fed, and hay price to determine hay needs and total cost. The calculator can also assist with hay quality analysis.

Based on several pieces of research, the method of storing and feeding hay significantly increase costs. Average storage losses for hay stored six months or longer range from 5 percent for hay in a barn to 30 percent for hay stored outside and uncovered. Hay stacked and covered with a tarp on a rock pad or pallets results in 12 and 14 percent loss respectively. Additional storage methods include a plastic sleeve and net wrap which result in average losses of 19 and 23 percent respectively.

Similar to storage, the method of feeding hay can influence hay loss. Feeding losses from feeding hay in a cone ring range from 2 to 5 percent while feeding hay in a conventional ring results in 4 to 7 percent hay loss. The use of a hay trailer generally results in 10 to 13 percent hay feeding losses while the use of a cradle will result in 15 to 20 percent losses. Unrolling hay on the ground has the most variability with losses ranging from 5 percent to 45 percent. Hay feeding losses are likely more a function of how much hay is fed at a time as opposed to the method. For instance, feeding a week’s worth of hay in a cone ring will result in more feeding loss than feeding one day of hay in a cone ring.

For illustration purposes, consider a producer with 30 cows averaging 1,200 pounds and feeding 2.5 percent of the cows body weight for 150 days. This would result in each cow needing 30 pounds of hay each day on a dry matter basis. Assuming 11 percent moisture would result in the herd needing 76 tons of hay or 152, 1,000 pound bales. If the bales cost $35 per bale then the total cost to the herd would be $5,320. However, storage and feeding loss have not been considered.

Now consider two management options with this herd: storing hay in a barn and feeding in a cone ring or storing net wrapped hay outside and feeding in a conventional ring. The first system of storing hay in a barn and feeding in a cone ring results in a total loss of 6.4 tons of hay or 13 bales of hay for an additional hay cost of $451 for the herd. The second system of storing net wrapped hay outside and feeding in a conventional hay ring results in a total loss of 21.6 tons of hay resulting in the need of 43 additional bales of hay and adding $1,513 to herd hay cost.

This basic illustration demonstrates changes in feed costs from differing hay storage and feeding management. Producers should consider methods of reducing hay storage and feeding losses to reduce total costs. Producers should also consider grazing management practices that reduce hay needs which have a potential of reducing feed costs.

Spring Manure Applications

Carefully Approach Spring Manure Applications

Appropriate timing is an important part of efficient manure application.

At this time of year you may be looking at a full manure storage and desire to get an early jump on application for the coming growing season. Patience can pay off in the form of manure nutrient conservation. After all, the goal of manure application is to place valuable nutrients on the soil where they are needed and to keep them there. A large part of this equation is timing. The closer the nutrient is applied to actual crop need the better.

The goal of manure application is to place valuable nutrients on the soil where they are needed and to keep them there.

Application of nutrients during times of snow-cover, frozen soil, or saturated conditions increases risk of nutrient loss. Once a nutrient passes the field edge it is lost to the environment – and lost from crop uptake. A fraction of both nitrogen and phosphorus in manure will be present in soluble forms. If the liquid solution of manure can infiltrate the soil then soluble nutrients will infiltrate with the liquid to a location that is safe from overland runoff. The ammonium nitrogen fraction will also be safe from volatilization after it is beneath the soil surface. Frozen, snow-covered, and saturated soil conditions hinder infiltration. Spring rain events can carry both the soluble and solid portions of manure from the field.

If you must apply manure before conditions are ideal, you should go to fields specifically listed in your nutrient or manure management plan to receive manure during the current season. Some things that limit risk of manure nutrient loss include fields with shallow slopes, fields with a perennial crop such as hay, fields with a cover crop, fields with lots of crop residue, and fields that are more distant to water. You should prioritize the order of manure application according to risk and go to the least risky fields first.

Because infiltration can be limited at this time of year, extreme runoff events can occur. For instance, snow melt or rain on frozen or snow-covered ground can cause runoff to occur from lands that rarely lose water. For this reason, it is wise to skip subtle swales in these fields where water can gather and flow. Nutrients placed here certainly won’t stick around. These shallow depressions can be covered with manure later in the spring when risk is lower. Pay attention to the weather forecast, and avoid situations where you expect upcoming weather may undo the nutrient placement work you have done.