It’s time to prepare for swine foreign animal diseases

Dr. Bret Marsh, Indiana State Veterinarian, spoke about the threat of a foreign animal disease (FAD) outbreak in the United States at the Four Star Veterinary Service Pork Industry Conference held in Fort Wayne, Indiana in mid-September.

“This is about preparation as it relates to foreign animal disease, and the challenges we could be faced with in this state and across the country along with identifying some of the challenges that are going on around the globe,” said Dr. Marsh.

In the map above, red indicates where African swine fever (ASF) exists around the globe; green is ASF-free.

“This is where it’s reported. My guess is it probably exists places that are not reported in red on this map. But as you can see, we have large portions of the globe that are green. We are fortunate here in North America to be in the green, but this virus has been on the move. And it’s presented some very unique challenges globally,” said Dr. Marsh.

ASF was first diagnosed in the continent of Africa in the 1930s. When it spread, a few countries like Spain and Portugal had success in eradicating the virus in the 1960s. However, virus spread has taken off in recent years, especially when China announced a diagnosis in August 2018. The Chinese outbreak and rapid spread across their provinces put North America on a higher level of awareness. The 2021 diagnosis of ASF in the Dominican Republic and Haiti suddenly put the virus much closer to the US border.

“This challenge exists not only for us here but anywhere on the continent and in South America,” he said. “This virus is a tough one. It’s a virus built to survive in the environment for long periods of time.”

ASF virus remains active in Dominican Republic and Haiti.

“Unfortunately, based on the last reports I’ve heard, the virus may be there for a while because of the economic challenges on the island and political unrest. In Haiti, for example, it’s one thing to get your diagnostic samples, but there’s no gas or fuel to deliver them to a diagnostic laboratory. The basic things we take for granted here are unique and insurmountable challenges there,” he said.

Classical swine fever remains a threat

Classical swine fever, historically called hog cholera, is a virus that the US has experienced. It was eradicated in the US in 1978. However, the island of Hispaniola not only has ASF, but it has had classical swine fever since 1997.

Classical swine fever currently is found in Central and South America, Europe and Asia and parts of Africa. North America, Australia and New Zealand are currently free of the disease. In the 1990’s large classical swine fever outbreaks occurred in The Netherlands, Germany, Belgium and Italy.

“This virus is alive and well and exists in large areas across the globe, and you just need to be aware that it exists not far from our shores as well,” he said.

Foreign animal disease preparedness

The question goes beyond how to prepare for a FAD on your farm. How does the US industry — and North America — prepare because the US swine industry is inextricably bound to the Canadian and Mexican pig industries?  Dr. Marsh said this became increasingly apparent in his recent experience with avian influenza outbreaks.

“It’s surprising the number of products right here in Indiana that go into the international market,” he explained. “You find that out because in a disease situation, you put an area around that infected site called the control zone. To move products in and out of that area, you have to have a permit. For example, one of the turkey companies here in Indiana ships 50 semitruck loads a week of turkey products to Mexico. It stopped [when avian influenza was diagnosed in Indiana] — just like that— those trucks were stopped at the border. We had to go through a negotiation on a timetable to continue to move that product. We’re just talking in a 10-kilometer area, that’s 6.2 miles. That’s all it took, and Mexico said no.”

If there’s a FAD suspected in your area, a 3-kilometer circle will be drawn around the site of the infected animal and that becomes the infected zone. Then a buffer zone will be established another 2 kilometers out from the original infected zone. The area as a whole is called the control area.  The control area will have restrictions on movement.

“If you’re outside of that zone, we hope that other states and other countries consider those as free areas and you can continue to move your product,” he said. “Otherwise, if you’re in that control area, there will be a permitting process for moving products in and out of the area,” he said. “If you’re on the infected side, we’re going to be trying to contain the virus until we can eradicate the disease. But it really depends on where you wind up. Basically, your preparedness plan should prepare for either of those eventualities:  If your site is infected and you’re in the control zone, or if you’re outside that area.”

There are many activities going on in the US swine industry to help producers and processors prepare for a foreign animal disease. Key programs Dr. Marsh discussed and encouraged producers to participate in:

Premise ID. Having a state premise ID is critical for rapid identification of farms in the control zone. This is important to be able to contain the virus as quickly as possible.

Secure Pork Supply Plan

  • Voluntary initiative that provides practical continuity of business plan in the event of a FAD disease outbreak
  • Focuses on three areas
    • Traceability and movement management
    • Enhanced biosecurity
    • FAD training and response

AgView

  • Free, opt-in technology solution from the National Pork Board that helps producers of all sizes and types provide disease status updates and pig movement data to state animal health officials
  • Designed to provide business continuity for US pig farmers by making disease traceback and pig movement data available to the USDA and state animal health officials on Day One of a foreign animal disease (FAD)

US SHIP (Swine Health Improvement Plan)

  • Designed to identify disease-free areas with monitored- and certified-status herds across the country
  • ASF-CSF Monitored certification aims to mitigate risks of disease introduction and provide a practical means for demonstrating evidence of freedom of disease (outside of FAD control areas) in support of ongoing interstate commerce and a pathway towards the resumption of international trade
  • Applicable across the full spectrum of US pork industry participants from the small show pig farmer to the large commercial producers and slaughter facilities
  • Modelled after the National Poultry Improvement Plan (NPIP) H5/H7 Avian Influenza Monitored certification held by greater than 99% of US commercial poultry operations

Certified swine sampler collector

  • New program for the swine industry
  • When an outbreak occurs, there aren’t enough veterinarians to test all the pigs, especially on an ongoing basis
  • This program recognizes the work of an accredited veterinarian to train individuals at the farm level to collect the appropriate samples and submit those samples to the appropriate laboratory
  • States maintain a repository on who’s been approved and certified

 Important things to know if there’s an ASF outbreak

FAD PReP/Red Book for ASF. This is a manual for high-consequence disease response in the US. The USDA maintains the content, and states execute. If there’s an outbreak in your state or region, download a copy and reference it.

Stop movement. Unique to an ASF outbreak, USDA will issue a National Movement Standstill of at least 72 hours after a detection in domestic or feral pigs. This is intended to allow states to gather initial critical information for a unified approach to an ASF response while inhibiting further virus transmission. Consider how this will impact your operation when creating your FAD plan.

 Feral swine. Any ASF diagnosis in the US will shut down US export markets. The infected animal could be a feral pig or domestic pig. Eradicating ASF in the feral pig population creates a unique challenge given the number of feral pigs found across the US. 

US territories.  In 2021, the US submitted a self declaration of the establishment of a protection zone for US territories in the Caribbean. This essentially sequesters Puerto Rico and the Virgin Islands from the 48 contiguous states in case of an ASF outbreak in either territory. Thus, if an ASF-positive pig is found in these US territories, it would allow US pork trade to continue with trading partners around the world.

ASF vaccine. An ASF vaccine hasn’t been approved yet, but Dr. Marsh said he is encouraged by some of the vaccine candidates that are being considered.

Dr. Marsh said a lot of work needs to take place now, while the US industry is negative, to ensure your operation is prepared and ready to respond if/when there’s an FAD outbreak. The US industry’s ability to quickly contain the virus during an outbreak will be crucial. Dr. Marsh encourages producers to consider their operations and work with their veterinary team to build an FAD preparedness plan, using all the tools at their disposal.

Managing calf environment best way to prevent Mycoplasma bovis

Mycoplasma bovis tends to hit calves early on in life, especially those born on dairy farms, according to Dr. Bryant Chapman with Four Star Veterinary Service in Ohio, noting that beef-on-dairy calves can be at risk, especially if they were not provided adequate amounts of colostrum.

While mycoplasma can also cause mastitis and arthritis, the major concern with the pathogen is with the upper respiratory tract and pneumonia. Mycoplasma bovis can lead to irreversible lung damage, can increase morbidity in infected calves and, in some cases, increase mortality, Chapman said, pointing out that this costs producers not only in calf losses but also in lost growth potential and increased medication costs.

One of the most tell telltale signs of an early mycoplasma infection is a unilateral ear droop — when looking at a calf, one ear will be pointed forward and alert while the other is drooping — which is fairly unique to mycoplasma infection, Chapman said.

Mycoplasma can present differently depending on type of cattle operation, he said — dairy calves tend to come down with it earlier in life than in beef calves that spend their first few months on pasture with their mother. Beef calves can develop mycoplasma when they’re weaned and put into more of a drylot housing scenario.

Generally, mycoplasma is a slower-moving pathogen, where a producer will be treating a couple of calves every week for multiple weeks, Chapman said. With other bacteria, a whole group of calves will get sick all at once. Once calves are around 400-600 lbs., they tend to grow out of it and have some immunity against mycoplasma, if they did not have much lung damage, he added.

Facility management

Mycoplasma likes to thrive in damp, humid environments, Chapman said. He said barns should be kept clean and dry with good ventilation to reduce the risk of Mycoplasma bovis infection.

Mycoplasma cells do not have a cellular wall, so it doesn’t live very long in the environment, he said, but studies have shown that Mycoplasma bovis can live within biofilms created by other bacteria or debris for months or potentially years. Without proper sanitation and disinfection, mycoplasma can move from one group to the next by residing within a barn if it is not cleaned out properly between groups.

Proper ventilation management is important, especially during winter when calves may be confined in barns. Producers want to keep their animals warm but humidity can then develop and allow mycoplasma to proliferate.

Treatment and control

As mycoplasma has no cellular wall, so only certain types of antibiotics will be effective against it, Chapman said. Antibiotics that target the cell wall, such as the beta-lactams, will not be effective, but other products such as the macrolides can be a good choice, he said, as long as they are used judiciously.

Long-acting macrolides can work well, Chapman said, because they remain in a calf for a longer period of time, which is important with the slow-acting nature of mycoplasma. Macrolides have also been shown to target the lungs where mycoplasma can cause damage.

Unfortunately for the control of Mycoplasma bovis, there really isn’t a “great vaccine, whether it would be autogenous or commercial for cattle,” Chapman said. There are companies that are trying to develop a vaccine, but so far attempts have been “pretty futile” in terms of true protection against mycoplasma.

Prevention is the best way to control mycoplasma flare-ups, which means targeting the environment, Chapman said. Producers should pay attention to keeping the calves’ environment dry, use appropriate bedding, and make sure the stocking density and ventilation rates are appropriate for their facilities. On dairy farms, there is the extra milking equipment handling and sanitation.

Organic farms

Organic producers really have to focus on environment to reduce the risk of mycoplasma infections, Chapman said, as they do not have the ability to treat calves with antibiotics.

He suggested organic producers look at practices that would boost calves’ immune system, such as making sure they have enough electrolytes in their water or adequate mineral nutrition, so that they have a strengthened immune system to fight off mycoplasma. He suggested trying essential oil and botanical products that have become available, but with the caveat that those products do not have clinical trials to support their efficacy.

Organic facilities really need to focus on what they can do before an outbreak because one a mycoplasma infection starts, there’s not much that can really dampen it, he said. “It’s through the setting up of the correct environment and potentially vaccination” — although the history of vaccines and this bug has not been the most successful — that organic producers need to focus on, including facility and equipment cleanliness, calf environment, and housing and ventilation, Chapman said.

Even for conventional farms, facility and environmental management are the first, key steps to reducing mycoplasma risk. Just treating calves with antibiotics “isn’t going to solve your problem” with mycoplasma, he said, because the problem will continue to flare up. Maintaining a clean, dry, draft-free environment also helps prevent other respiratory diseases beyond mycoplasma.

Mycoplasma bovis is a “challenging and frustrating bacteria” that most groups of calves are going to be exposed to, so producers need to stay on top of their facility and environmental management programs to reduce the risk of the disease and minimize its effect on growing calves.

Hemorrhagic tracheitis requires attention

Swine producers may be facing an emerging respiratory condition without really knowing about it.

According to Dr. Michael Pierdon with Four-Star Veterinary Services in Pennsylvania, hemorrhagic tracheitis syndrome (HTS) is a clinical respiratory condition that has been identified in pigs that presents with a characteristic gross lesion on necropsy of hemorrhage in the trachea (windpipe) that becomes obstructive. The lesion causes severe coughing and, due to the restricted airway, high mortality.

The pigs develop a hemorrhage underneath the mucosa of the trachea, which creates a “blood blister, for lack of a better term,” that restricts the airway and causes issues with breathing, and ultimately, causes death, he said.

HTS primarily affects growing pigs, with the most dramatic outbreaks occurring in heavier finishing pigs, maybe 125-lbs plus, in Pierdon’s experience. He said he has diagnosed it in younger pigs, including in the nursery, although the severity of the gross lesion is less impressive in younger animals and the mortality doesn’t tend to be as high.

According to Pierdon, mortality rates are in the 1%–2% range. With a sudden acute outbreak of respiratory disease in mid- to late-finishing, with 1%–2% mortality over the course of a week, the losses can be substantial.

HTS is not new, he added, noting that the Swine Health Information Center held a webinar on it in 2020, but it hasn’t gotten a lot of attention because the trachea is not a tissue that is often examined or collected during a routine field necropsy.

The causative agent(s) are also yet to be determined, Pierdon said. “With respiratory conditions, people think lungs. What really put me on the trail of this is finding respiratory outbreaks with severe coughing and high mortality and sudden onset in mycoplasma-negative flows that we would oral-fluid test and find negative for PRRS and influenza.” he said.

While there are really severe lesions inside the trachea, the lungs often do not have significant lesions, he said.

HTS could easily look like influenza, and even that kind of mortality would be typical in an influenza outbreak in late-finishing pigs, Pierdon said, but it’s really telling when there are respiratory outbreaks that test negative for influenza, but those pigs still have those signs.

Clinical management

According to Pierdon, HTS outbreaks should be treated symptomatically with anti-inflammatories and sometime expectorants. He said antibiotic treatments are not particularly helpful given that there hasn’t been a consistent bacterial diagnosis associated with the condition and the affected animals tend to be heavy, market-ready hogs.

He added that it seems to be highly contagious within a barn with symptoms developing over a short period of time (24–72 hours), with the duration of clinical signs lasting 7 to 10 days.

With its rapid onset and lack of definitive cause, Pierdon said it is hard to get in front of the outbreak so it needs to run its course while supportive therapy is provided to clinically manage the pigs through the outbreak.

Critical actions

Pierdon’s goal is to raise awareness of this syndrome or clinical condition as a way of encouraging people to actually open the trachea and look for it. If a barn of pigs experienced an outbreak and oral-fluid samples tested positive for influenza, the assumption would be that it was an influenza case. Pierdon’s hypothesis is that it can’t just be him in Pennsylvania that is finding this problem and he wants other people to know to look at tracheas so those samples can be sent to the diagnostic labs. From there, the diagnosticians and epidemiologists can have more opportunity to try to figure out the actual cause of HTS. If it can be demonstrated that HTS is more common than believed, research funding may become available to further study and understand the problem better.

Pierdon said the lesions are most commonly found inside the trachea between the larynx and the thoracic inlet – in a market hog, about 4 in. behind the larynx. The lesions are most apparent when the trachea is cut in cross-section, he added.

He encouraged swine producers with pigs exhibiting acute and sudden outbreaks of coughing associated with mortality to have pigs necropsied, including an examination of the trachea. Producers can do this themselves or have a veterinarian investigate, but the point is to open the tracheas.

Veterinarians finding HTS lesions should include fresh and fixed pieces of trachea in their diagnostic tissue submissions to the diagnostic lab of their choice for gross diagnosis and histopathology.

By encouraging samples being submitted to diagnostic labs, Pierdon hopes a critical mass of confirmed cases will demonstrate the scope of the problem and make funding available to better understand HTS.

Solving sow lameness starts with prevention

Lameness issues continue to be a significant problem in sow herds, causing 40% to 50% of all sow removals, according to Bill Minton, DVM, Four Star Veterinary Service in Chickasaw, Ohio.

“What hurts most is when the culling for lameness occurs at 3rd parity,” Minton said. “It takes almost to the 3rd parity to break even on the cost of raising, acclimating and getting that animal into production. We are removing animals we haven’t even paid for. This has become a significant cost that is often overlooked.”

Minton advocates taking steps to reduce lameness problems early and to increase sow longevity up to 7 parities in herds. Not only will this lower costs in a system, it will improve worker well-being by not having to deal with the problems associated with lame sows.

Pay attention to gilt selection

Many lameness problems can be prevented by selecting gilts ahead of time, he explained. Producers should try to evaluate incoming gilts as soon as possible before entering the herd. This can be done in the grow-development units or during the quarantine period. Ensure gilts are structurally sound and the right age and weight before bringing them into a sow unit.

He recommended taking a good look at how gilts move and walk in a pen. Make sure the animals have good body confirmation, good hoof quality, and stand well on their feet. They should not be stiff gaited or have long toes.

The best size and weight for gilts entering a sow unit is around 300 lbs. and 28-30 weeks of age, he added. If gilts must be brought into a herd earlier, consider skipping a heat cycle to help the gilt develop adequate body condition.

“Put an emphasis on bringing in the right quality animals,” he said. “Spend some time selecting gilts. We easily overlook this and assume everything is okay. Then we bring in animals [to meet breeding targets] and it backfires in the long run.”

Watch every sow every day

Better observation of sows in gestation is key to reducing lameness issues that lead to culling, Minton emphasized.

“In gestation, make sure you get up every sow and observe every one for signs of early lameness,” he said. “Observe sows especially at feeding time to see if they are shifting weight, tapping a foot, or not bearing equal weight on all four legs. Do they have any swelling, cuts or bleeding? Observe sows while walking through the gestation barn or farrowing rooms.

“If we know what we are looking for early enough, we do have the opportunity to treat lameness,” he explained. “Oftentimes we intervene too late and don’t get a response out of our treatment.”

Treatment options

If the decision is made to treat an animal, Minton said there are several options depending on the cause of lameness. For health-related problems, products such as systemic antibiotics, pain relievers and anti-inflammatory products may help if problems are caught early enough.

Because nutritional deficiencies can also lead to lameness, review sow rations to determine if there are nutritional concerns. The addition of some trace minerals like biotin and zinc may help improve hoof strength, Minton added.

Providing individual sow care is another option. “Even special attention and TLC for some animals will help,” he said. “Remove them from a pen and put them in a hospital stall with a rubber mat for better footing.”

Hoof trimming can solve some lameness issues. “It helps especially for those long dew claws or an outside toe that’s quite a bit longer than the inside toe,” he explained. “We can use lopping shears and trim that off. A lot of times that will correct the confirmation of the animal so she is more comfortable walking.”

Another suggestion is using copper-sulfate foot baths. Minton said copper sulfate is an antiseptic for the hoof, which can help improve hoof strength. He suggested providing the foot baths for gilts when entering the sow barn and sows to walk through when moving between farrowing and gestation units.

Maintain good housing, environment, handling

Many other factors cause lameness in sows and gilts. These range from different types of housing, flooring, air quality and temperature to poor handling and fighting among animals.

Producers need to maintain a good environment and housing with proper animal handling procedures to minimize lameness issues. Overcrowding, improper ventilation rates, mycoplasma or erysipelas, and the health status of incoming gilts are a few factors that can lead to lameness.

Minton suggested using treatment-card data and other records to identify trends and specific issues that may be causing problems within a unit. It will offer guidance on areas that could be addressed.

“I think a lot of lameness is preventable and some of it is treatable,” he added. “But ultimately, it has a negative impact on sow culling and mortality. Intervention will have a positive impact on the sow herd.”

Reappearance of F18 E. coli strikes nursery pigs

A resurgence of the F18 strain of Escherichia coli (E. coli) in weaned pigs on a growing number of hog farms is causing a rise in mortality and a reduction in performance, according to Doug Powers, DVM, Four Star Veterinary Service.

“We used to have the F18 E. coli or edema disease a long time ago,” Powers related. “With the work of veterinarians and nutritionists, we eliminated a lot of it. So it’s remarkable that we’ve seen an increase starting in 2020. And in 2021, we’ve seen a huge uptick in the F18 E. coli.”

Powers has seen some farms experience 30% nursery mortality during an F18 E. coli outbreak. In less serious cases, morbidity can reach 60% to 75% of the animals and reduce average daily gain and feed efficiency. In addition, the immune response of affected pigs to vaccines administered in the nursery phase may not be as good as expected.

Why the increase in F18?

“We still are not certain why the increase, but part of it is we are using less antibiotics in sow herds,” Powers said.

“The other thing is we’ve seen a high divergence of genetic terminal stock to Duroc,” he continued. “It appears from research that Duroc-sired animals have four times the amount of receptors available to attach to E. coli than other sire lines. It makes them more susceptible to E. coli.

Another piece of the puzzle is what other bacteria disrupt the gut and “opens the door for E. coli to become so severe,” Powers added. “We are finding ileitis and Salmonella in both the sows and pigs.”

After working with clients battling the F18 E. coli, Powers explained the steps they took to mitigate the effects of the bacteria in some herds.

Address sow bacterial loads

Powers first looked at the sow herd to determine the bacterial loads and how to halt the infections. “One way is to do a strategic antibiotic pulse to the sows to try lowering that infection rate,” he said.

“We also looked at products like zinc oxide to reduce bacterial loads,” he said. “We’ve had really good success with zinc oxide.”

Next they determined any co-infections in the pigs and discovered Salmonella was usually present and helped allow E. coli to become established.

His choice was to vaccinate pigs with a Salmonella vaccine just prior to or right at weaning instead of vaccinating for the F18 E. coli strain.

“The Salmonella vaccine helps prevent the binding of E. coli to those receptor sites because the Salmonella takes up those spots instead,” he explained. “So if we vacinate for Salmonella, we are getting benefits against E. coli as well. This has reduced the E. coli infections dramatically.”

Attention to the diet

Powers said they also worked closely with nutritionists at all the farms to modify pig diets and lessen the impact of E. coli.

“We can modify diets in the early phase right after weaning to have higher-fiber, lower-energy diets that are not so reactive to the pig’s gut,” he expained. “We try to improve the overall health of the gut to prevent the E. coli from binding to the receptors.”

They also are trying new products called endotoxin binders. These can help prevent E. coli from being absorbed by pigs.

Powers has seen significant improvements in a majority of the herds experiencing F18 outbreaks when they’ve taken these steps.

Watch for problems

But things can quickly go wrong if other issues occur to delay feed delivery to the newly weaned pigs, or the wrong feed is put into the feed bins and then fed to the pigs.

“It’s important to work with producers to reduce problems like out of feed, the feed mill can’t deliver, labor issues, or the motor on the feed bin quit,” Powers said.

“If pigs go without feed for 12 hours or more, we will see an increase in intestinal issues,” he added. “Those pigs have to have feed and water in front of them in a good environment.”

 

 

 

 

Early pregnancy testing in a beef herd pays off

Pregnancy testing cows in a beef herd can help producers make better management decisions to improve their bottom line. But the tests must be conducted early in pregnancy when the accuracy is high, reported Brittney Scales, DVM, Four Star Veterinary Service.

“Reproductive efficiency in the cow herd is extremely important,” Scales said. “Pregnancy testing is a good method to monitor the herd and help make management decisions such as when and who to cull.”

Scales offered several steps producers can take to plan ahead for this coming year’s pregnancy testing and use the results to improve reproductive efficiency of their herds.

Well-defined breeding season

Scales recommends a well-defined breeding season to ensure accurate pregnancy testing. A breeding season is defined as the time from the day the bull goes in with the females to the day the bull is pulled out. If bulls run continuously with cows and aren’t pulled until pregnancy testing, some late-bred cows will appear open and may be culled unnecessarily.

The breeding season should fall within a 45- to 60-day window, according to Scales. Heifers are very healthy and should need only two estrous cycles to get bred, while cows will need more time. The estrous cycle is approximately 21 days long; therefore, a 45-day breeding season gives females two chances to get bred.

“Our goal is to have 80% to 85% of heifers bred within a 45-day breeding season and 90% to 95% of cows bred within 60 days running with a bull,” she explained.

Pregnancy testing time, options

Pregnancy testing can be conducted as early as 30 to 45 days after the last day the bull comes out, according to Scales.

Options for pregnancy testing are ultrasound, rectal palpation and blood tests. Trained individuals and veterinarians can conduct these tests.

“Typically, ultrasound diagnosis can be used within 30 days post-breeding,” she explained. “You can catch a pregnancy a little earlier with ultrasound around 30 days, whereas rectal palpation can determine a pregnancy closer to 45 days, depending on the expertise of the pregnancy tester.”

Blood tests are another option but come with some complications. If a cow or heifer aborted right before the blood draw, the tests would produce a false positive, Sales said.

Fetal viability, sexing

An advantage to ultrasound is the ability to determine fetal viability. This is not possible with a blood test.

“In ultrasound we will see the heart beating and can give a more defined fetal age based on size of the fetus,” she said. “If you want to know where she’s at in gestation, the earlier the pregnancy check — 30 to 45 days up to 100 days — the better. After that, the calf starts to drop below the pelvis, and the accuracy of gestational age declines.”

Fetal sexing is an advantage of ultrasound. At around 60 to 65 days of gestation, ultrasound can determine if the cow is carrying a bull or heifer calf.

Check for other issues

The use of rectal palpation and ultrasound will also identify if a cow or heifer has cystic ovaries or uterine infections. “Both negatively affect her reproductive performance because she won’t get bred,” Scales said.

These pregnancy tests can also differentiate twin calves. “It’s always good for a producer to know if a cow is going to have twins because she’s more likely to have problems calving,” she added.

Manage open cows, heifers

“Now that we have information on which cows are open and which are bred, the producer has some options for managing these open cows and heifers,” Scales said. “Open cows can be weaned early from their calf and sold.

“If we preg-check early, the cull cows can be sold prior to the historic market lows,” she continued. “Most people preg-check herds very late going into fall, so all these open cows hit the market at the same time, lowering market prices.”

Another option is moving open cows into a fall calving group if the herd calves twice a year. Regarding heifers, open animals can be sold immediately or managed and sold as feeders. Another option is to retain them and breed them for a later calving season.

These are some of the financial benefits to knowing early what cows and heifers are open, Scales explained.

“Thinking ahead, a lot of people will be calving in late winter/spring,” she said. “Scheduling an early pregnancy test this coming summer will help your bottom line. And remember to consult with your veterinarian about your individual operation and goals regarding your herd.”

 

Little-known sapovirus causes diarrhea in baby pigs

A couple of puzzling cases of diarrhea in baby pigs that didn’t test positive for the usual culprits were recently identified through genome sequencing as a porcine sapovirus, reported Daniel Hendrickson, DVM, Four Star Veterinary Service in Farmland, Indiana.

The diarrhea started in baby pigs at 6 to 7 days of age with symptoms similar to coccidiosis, but testing was negative. That’s when Hendrickson had the samples tested by polymerase chain reaction, and the sapovirus was discovered.

“I hadn’t heard much about sapovirus,” he admitted. “It is now another virus veterinarians and producers need to check when they are trying to reduce scours in the farrowing house.”

Sapovirus symptoms

Since porcine sapovirus was discovered in US swine herds 40 years ago, little attention has been paid to the virus. But improved testing methods now commonly detect sapovirus as a co-infection in diarrhea outbreaks and the sole cause in a few other outbreaks.

Hendrickson first learned of the virus when working with a couple of farms to clear up scours in the farrowing barn.

“They thought scours was pretty much under control, but they kept seeing a scour at 6 to 7 days of age,” Hendrickson explained. “It would last a few days and was a pasty scour like coccidia, not watery like Escherichia coli, rotavirus and some other viral baby pig scours. We would only find some rotavirus in the first few days after birth, but then testing would go negative.

“It’s not high mortality, but pigs go backwards pretty hard for 2 to 3 days,” he added. “The pigs at weaning will recover but will be 1 to 2 pounds smaller because of those couple of days of scours.”

He also was working with another client that had battled diarrhea for a couple of years and decided to check for sapovirus. Tests came back positive for the virus and showed very high loads of it.

Care and treatment

During a sapovirus outbreak, Hendrickson suggested keeping the pigs dry and well hydrated. Also make sure the sow is milking well. Most outbreaks last 3 to 4 days but can reoccur.

“We’d have a few weeks where it was pretty bad, and then it would get better for a month,” Hendrickson said. “Then it would creep back, and I knew the immunity was waning.”

Initially, he tried a feedback program but had little success. Then he moved to vaccinating the sows at 4 weeks and 1 week pre-farrowing, which provided consistent immunity.

“I think sapovirus is endemic in the sows and their environment,” Hendrickson said. “Cleaning and disinfection are critical to lower the virus level in the environment.”

More information

In 2015, the Swine Health Information Center produced an information sheet on sapovirus, available online at Porcine Sapovirus.

More information is also available at: Porcine sapoviruses: Pathogenesis, epidemiology, genetic diversity, and diagnosis.

 

 

 

 

Cold stress poses threat to calf health even at mild temps

Cold stress can become a drag on growth rates if calves aren’t kept warm and dry even at temperatures as high as 60° F.

“For every 2 degrees below the critical temperature, which is 60° F for calves up to 21 days old, they need 1% more energy just to stay warm,” reported Trey Gellert, DVM, Four Star Veterinary Service. For calves over 21 days, the critical temperature is 42° F.

“I think many producers don’t realize calves can be experiencing cold stress over half the year and probably two-thirds of the year in Ohio and Wisconsin,” he said.

Other factors such as wind chill, drafts, moisture and humidity increase cold stress, and calves will expend even more energy to stay warm.

Gellert offered some strategies to reduce stress on calves.

Increase energy for winter

“The biggest issue I see is not changing the milk-replacer feedings for winter and keeping them the same as summer,” Gellert said. “The amount of energy given to calves from the summer to the winter should increase.”

He recommended increasing the amount of milk replacer and extra feedings during winter.

“We know those calves are experiencing cold stress, and they have to use energy to stay warm,” he added. “The biggest opportunity for feeders is to keep those calves warm with more feed.”

Prior to winter, Gellert suggested gradually increasing feed to help calves improve body condition and build a natural layer of insulation to help them handle cold temperatures.

Maintain good bedding

Calves need clean, dry bedding to stay warm and healthy. Gellert prefers straw bedding over sand or sawdust because calves can huddle into it and keep warm.

“Having good-quality bedding during the winter is an economic benefit because the animal is able to properly regulate body temperature,” he said.

“Generally, the health of the animal will improve if it is not using energy just to stay warm,” he added. “Average daily gain and feed-to-gain ratio will improve.  And the more bedding used, the better it is.”

Wet bedding that’s either muddy or contaminated by scours or other disease should be changed to prevent cold stress and illness.

“If they don’t have good bedding and are sitting in mud, that’s a double whammy,” Gellert said. “It pulls all the heat out of those calves.”

Wind, rain protection

The worst conditions for calves are outside in rain and wind. Cold stress quickly sets in, and the energy requirements to stay warm increase.

Gellert suggested using some type of wind break to help the animals stay out of the wind, as well as a shelter to stay dry. The best option is a barn to house the animals.

Calf jackets for newborns and, in some cases, calves up 16 weeks of age can also help them stay warm and dry. Jackets may also be needed for calves housed inside during the winter.

“When it’s 0° F outside, calves are still experiencing cold stress even when in a barn,” he said. “Those low critical temperatures really [adversely] affect them.”

Producers need to pay attention to cold stress in their young animals and take steps to help them stay warm.

“The health of the animal will improve if they are not using energy to stay warm. They will use energy to stay healthy and grow,” he said.

Managing Strep suis in commercial pig production

Most, if not all, pigs harbor some strains of Streptococcus suis (Strep suis). Lately, challenges by the bacteria appear to be on the rise, but that could be interpreted as a positive.

“It’s up for debate whether Strep suis is on the rise. It could be we’re doing things to make Strep worse or we have better diagnostics, because it’s always been around,” reported Daniel Gascho, DVM, Four Star Veterinary Service in Mexico, Indiana.

If producers have an outbreak of porcine epidemic diarrhea or porcine reproductive and respiratory syndrome, then Strep suis often takes a back burner, he said.

“I view producers wanting to tackle minor Strep suis as a good thing because it means they’ve fixed the really big problems,” he continued.

Common in post-weaning

Most Strep suis outbreaks occur in post-wean pigs when drastic changes are made to their living situation and new stressors are added.

“We can see primarily pathogenic Strep in the farrowing house, but without a doubt, post-weaning is where I see the most flare-ups of what I’ll call normal StrepStrep that’s typically not a primary pathogen and is a commensal organism that just flared up because the pig’s immune system was weakened.”

In these cases, Gascho recommends focusing on husbandry like room temperature, humidity levels, stocking density and proper nutrition. In addition, more pigs may need to be moved to hospital pens for individual treatment. If the outbreak is serious enough, water medications or other treatments may be warranted.

“But the big thing is if you can head off Strep before it starts, you’ll be miles ahead,” he said. “Just focus on all the normal husbandry items to the best of your ability.”

Serious flare-ups

There are times when Strep suis requires immediate intervention. These occur with more pathogenic strains that can lead to meningitis and death.

“If it’s one of those types of Strep, we need to treat now because the pig won’t last very long,” Gascho said. “This is the Strep we get the most calls about because it kills pigs.”

Most farms assume Strep suis is causing the meningitis and will treat accordingly. However, if treatment seems to be failing, a lab diagnosis should be conducted from a brain sample because there are other causes of meningitis requiring different treatments.

“The bigger picture is where did that pathogenic Strep suis come from?” Gascho said. “How do we keep that from happening again?”

Common solutions

“Strep is not typically a hardy bacterium; many drugs or antimicrobials licensed for use in swine have a label for Strep suis,” Gascho said. A few of these include ceftiofur and enrofloxacin products.

“If you have a late-stage Strep suis, some dexamethasone to decrease intracranial pressure will buy that pig a few more hours of life to allow your antimicrobials to work,” he added.

In the end, reducing Strep suis challenges will require keeping the pathogen under control through good husbandry practices.

Strep has been around as long as pigs have been domesticated; we haven’t knocked it out yet, and we won’t,” Gascho said. “Just keep doing your basic husbandry to keep it from starting, which is easier said than done, but that’s the key.”

Check with your Four Star veterinarian to develop a husbandry plan or a treatment plan for Strep suis on your farm.