Common mistakes to avoid during PRRS elimination

Eliminating porcine reproductive and respiratory syndrome (PRRS) virus from a breeding herd is not a simple task, and no herd acts exactly like the next, according to Brad Leuwerke, DVM, with Swine Vet Center, St. Peter, Minnesota.

Looking back at years of PRRS elimination efforts, Leuwerke led a retrospective analysis of several breeding herds to determine why some were able to stay on course and achieve success while others were unsuccessful.

“We assessed several factors thought to influence a return to PRRS stability,” he said. “We found the season when the outbreak occurred, the virus strain causing the outbreak and the herd’s previous PRRS status all substantially affected the time necessary to eliminate the virus from the breeding herd.

“Largely, though, it feels like these factors are often out of our control.”

The review did highlight four factors producers can control that help drive successful virus elimination. “Failure to account for these aspects will extend the time necessary to achieve negative status,” Leuwerke said.

1) Avoid premature replacement entry

Producers must resist the urge to bring in extra replacement animals as a herd closure progresses. If replacements are brought in before the virus is eliminated, these animals will become infected and the closure time is drawn out.

“Instead, herds should ‘load up’ with replacements at the beginning of the closure to withstand the temptation to open up before the virus is eliminated,” Leuwerke said. “In addition, a reduction of culling, starting early in the closure, will also help in maintaining production goals without needing to open the herd.”

2) Set ‘day zero’ with an entire herd exposure

Start the PRRS elimination on a specified “day zero” using direct virus exposure of the entire herd.

“Infecting the entire population at one time allows for the shortest closure possible and is preferred over allowing the virus to naturally move through the population,” Leuwerke said.

This is especially important with newer, more virulent PRRS strains that look to have longer periods that animals shed virus.

3) Manage farrowing biosecurity

As a breeding herd nears the end of the closure, farrowing is the last place the virus can be found.

“The last animals to harbor and shed virus will do this through piglets, either born virus-positive or infected following birth,” Leuwerke explained. “Our biosecurity practices late in a closure influence the length of closure and, ultimately, if elimination is successful.”

At this stage, pigs should not be held back at weaning for more growth. “This is one of the worst things we can do in a sow herd working towards PRRS-negative status,” he said. It will extend the time of elimination.

Farrowing sanitation is very important, and poor practices can cause the elimination to fail. Leuwerke recommends all-out farrowing rooms at weaning so the rooms can be thoroughly washed, disinfected and dried. Common hallways also must be washed after all pig movements.

Good hygiene with processing tools must be practiced, too, to prevent the virus from spreading between litters.

4) Monitor herd status

“Newer monitoring strategies that allow us to test more animals have given us more confidence that a herd is truly negative before reopening to replacement animals,” Leuwerke said.

These new strategies include the use of processing fluids from many animals in the population.

“Before the use of processing fluids, we often would blood test 30 piglets each month,” he explained. “If we had 3 consecutive months negative, we called the herd negative. We likely missed virus using these testing procedures.”

Leuwerke admits PRRS eliminations are difficult. But good planning before a herd closure starts will help avoid common mistakes that lead to elimination failures.







When swine medicine crossed over to human medicine

The tools used countless times to eradicate disease in sow herds and on hog farms became the tools to help pork packing plants reopen last spring after shutting down due to COVID-19. In an unusual turn of events, swine medicine crossed over to human medicine and helped quell COVID-19 outbreaks among plant workers and their families.

Veterinarians involved in the unprecedented effort spoke in a session at the 2021 American Association of Swine Veterinarians meeting. Tim Loula, DVM, led the effort with help from Paul Yeske, DVM, both of Swine Vet Center, St. Peter, Minnesota. Also closely involved were David Bomgaars, DVM, with RC Family Farms, Orange City, Iowa, and Brad Freking, DVM, New Fashion Pork, Jackson, Minnesota.

Plant closures

“When we started to hear about the COVID-19 problems, never did we imagine that slaughter capacity would be the biggest challenge that many producers and veterinarians would have to deal with,” Bomgaars related.

While pork-processing plants were deemed essential and could stay open during the pandemic, COVID-19 outbreaks sparked alarm among workers, their communities and local government officials. Soon, plants in Minnesota and Iowa cut back production and some completely closed.

A growing backlog of market hogs created great alarm in the pork industry. Producers and veterinarians worked on ways to handle backlogs while waiting for processors to reopen. But the processors didn’t know when that would happen.

Connecting with medical teams

“It just seemed like nobody was doing anything to get an answer on how to get these plants back running,” Bomgaars said. “Tim Loula and I discussed the need to get the human medical community involved in this process. We needed to better understand the prevalence, exposure, severity and asymptomatic rate of COVID-19.”

Bomgaars started seeking connections in the medical community. He contacted the CEO of his local hospital in Orange City and was provided a connection with Sanford Health, a major medical system in Sioux Falls, South Dakota. Sanford’s chief medical officer was willing to work with Bomgaars and other veterinarians to develop a plan for testing workers and getting packing plants back in operation.

“The medical doctors’ response was very encouraging,” Bomgaars related. “I was also talking with Roger Main, DVM, at the Iowa State University (ISU) Veterinary Diagnostic Lab. It was taking the state hygienic lab 10 to 12 days to get COVID-19 tests completed. The ISU lab has been running over a million PCR (polymerase chain reaction) tests a year. They helped the hygienic lab expand to run PCR tests. There was tremendous collaboration with human-health providers in Iowa.”

Both Loula and Bomgaars discussed their experiences eliminating disease in a hog population with the medical doctors. They explained how they used testing to assess the infection and immunity in populations of hogs. This same process could be used to assess COVID-19 infections in workers.

“Dr. Loula’s basic premise is we need to get testing and build confidence in what’s occurring so people will come back to work,” Bomgaars said. “Through collaboration with veterinarians, epidemiologists and health care providers, he developed a testing algorithm.”

The COVID-19 algorithm

The algorithm is a roadmap for handling COVID-19 test results and getting packing plants open (link to algorithm). All workers are tested either with a PCR or antibody test. Those testing positive on the PCR must quarantine and retest weekly until negative, which is when they can return to work. Workers who test negative can work unrestricted but must continue to be tested on a regular basis.

Workers testing positive on the antibody test must follow-up with a PCR test, according to the algorithm. If the PCR is negative, they can go to work. But if the test is positive, they must quarantine and be retested weekly by PCR until they have a negative test.

“This plan was to test everyone and keep them from spreading to other workers,” Bomgaars explained. “It definitely helped keep other processing plants operating.”

Workers were managed according to their health status to decrease health risk and promote worker safety. The negative PCR and immune (positive antibody test, negative PCR test) populations could work together. Initially it was proposed that these workers and families were housed in hotels or dorms to stay safe. The positive PCR with positive antibody test were at very low risk of shedding if showing no clinical signs. They were segregated in the plant or worked different shifts from the rest of the population.

“In the initial testing, it was amazing how many workers were asymptomatic,” Bomgaars said. “One plant had 2,400 people tested with 40% PCR positive and well over half showing no clinical signs. At another plant, 370 workers tested positive, and all were asymptomatic.”

Building worker trust

The algorithm helped packing plants get back in operation. And those that didn’t close were able to stay at near capacity by taking steps to test and manage workers to stop the spread of the disease.

“We also noticed a very personal response with education and explanations about the situation in languages that people could understand,” Bomgaars added.

During the really tough times of the pandemic, gift certificates were purchased from local restaurants for take-out food and given to plant workers. On weekends, Bomgaars said they had truckloads of food brought in and donated to the workers, too.

“Doing things that show you care about their health and family had a major impact on worker confidence that you want to do what’s best for them,” he added. “That’s a huge thing we learned in this process.”

The veterinarians also took home some good lessons about working with their human medical counterparts. “Local health workers understood that veterinarians are used to population medicine, and human medicine is more attuned to individuals,” Bomgaars explained. “They learned new methods of thinking. And the synergy that occurred in those situations was remarkably good. We may need this again.”


Antibiotics properly timed during PRRS virus outbreak reduce reproductive failure

An outbreak of porcine reproductive and respiratory syndrome (PRRS) on a sow farm will trigger reproductive failure in gestating sows. While PRRS is a viral disease, it causes endometrial inflammation leading to abortions, stillborns and mummified fetuses.

Ross Kiehne, DVM, with Swine Vet Center, conducted a study to evaluate the use of the injectable antimicrobial Draxxin® (tulathromycin) administered to gestating sows during a PRRS virus outbreak. Specifically, he wanted to see how administering the antibiotic at different stages of gestation affected the rate of reproductive failure.

On-farm investigation

The investigation was conducted on a 2,500-sow farm in northeast Iowa that broke with PRRS virus in mid-2019. The first 5-mL dose of Draxxin was administered to gestating sows 5 days after the outbreak was detected. A live viral inoculation (LVI) was performed 2 days later. A second round of the antibiotic was administered 13 days after LVI. About 20% of the sows were not treated, and these animals served as a control.

Data collected for the study was based on the pregnancy stage when the first antibiotic treatment was administered. The gestation stages were day 0-18, day 19-29, day 30-49, day 50-69, day 70-90 and day 91-105.

Kiehne used four reproductive outcomes for analysis: 1) abortions, culls and death; 2) farrowed and found open; 3) preg-check negative; or 4) repeat mating. The number of pigs weaned per sow was also determined for each animal enrolled in the study.

Positive outcomes in later gestation

The study verified Kiehne’s hypothesis that while administering Draxxin during early gestation is detrimental, it is beneficial during later gestation.

“Administering this antibiotic during early pregnancy appears to increase negative outcome events such as found open, preg-check negative and repeat mating,” Kiehne said.

“However, there appears to be an advantage to administering it in a PRRS virus situation after 50 days of gestation,” he continued. “This advantage is apparent in a reduction in abortions, stillborns and mummified fetuses and increase in total pigs weaned.”

Overall, the study found the percentage of sows that farrowed was higher for those given the Draxxin treatment at 68.5% versus 64.1% for the control sows with no antibiotic. Sows with abortions was lower for those receiving the Draxxin treatment at 17.4% versus 22.9% for the control group. Sows not pregnant was 6.9% for those given the Draxxin treatment and 6.7% for the control group. The deads and culls category was 7.2% for sows receiving the Draxxin treatment and 6.3% for the control group.

Weaned pigs per enrolled sow was calculated in each pregnancy group. In the early pregnancy stages, weaned pig averages were lower for sows receiving the Draxxin treatment compared to controls. After day 50 of gestation, the number of weaned pigs increased for sows receiving the Draxxin treatment compared to the control group.

In conclusion, Kiehne recommends administering the injectable antimicrobial Draxxin to sows after day 50 of gestation during a PRRS virus outbreak. However, administering it any earlier would be detrimental.



Pork industry struggled but found its footing during the COVID-19 crisis

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The pork industry entered one of its darkest periods in spring 2020 when COVID-19 forced the shutdown of several pork packing plants. Paul Yeske, DVM, Swine Vet Center in St. Peter, Minnesota, helped hog producers in the area work through the closures.

“Unfortunately, we were in the middle of the first plants that ended up closing,” Yeske said. “The biggest concern was that we didn’t know when the plants would open again, and we didn’t know [at] what capacity.

“As more things started to happen, the plants learned how to manage it more,” he continued. “I think that helped further down the road for people who were involved later to be less impacted.”

‘The wheels came off’

During the turmoil, the pork industry realized its efficient pork-producing and processing system had no room for errors.

“I think we learned just how good a system we had on a just-in-time delivery,” Yeske explained. “Producers and packers had been incentivized every step along the way to make the system more efficient and to have no slack in it.

“All of a sudden we couldn’t operate it, and then the wheels came off the wagon pretty fast.”

At that point, tough decisions faced producers, including euthanasia. “I think no one understands just how hard it is on people until they have to do it,” Yeske said. “No one can really appreciate that until they have to make that decision…and have to actually physically do the job.”

It was also something the pork industry thought it was ready to handle in the case of a foreign animal disease but really was not.

Best-laid plans gone awry

In 2019, Yeske was part of a table-top exercise with USDA to formulate plans for a foreign animal-disease outbreak. He said he thought they devised good plans to handle a catastrophe, but COVID-19 proved the plans were inadequate.

“Some of the things we thought we knew, we didn’t,” he said. “When you have to do a mass depopulation, you have to look at…how do we do it in a humane way? How do we do it in a safe way for the people? And how do we deal with the numbers?

“Ventilation shutdown was one of the things used in avian influenza outbreaks…It certainly was used here as well, but it’s not as easy as you think,” he added.

Always willing to innovate, the pork industry devised alternatives including the use of large-scale CO2. Trailers and later dump trailers with CO2 were among the best options, Yeske said. To help the pork industry, the state of Minnesota set up composting facilities to handle carcasses in two central locations, which could be done since no disease concern was involved.

Making the best of it

“I’d say today we’re probably better off to handle mass euthanasia if we have to than we were before, so that’s one of the good things that came out of this situation,” Yeske said.

Another positive is some farms used this time to reset herd health by closing and cleaning up.

Ironically, the spread of COVID-19 among hog farms was not a major issue. Hog farm staff already were well acquainted with biosecurity regimens and understood viral transmission of disease.

“The swine industry has been working on that for a number of years,” Yeske added. “I think we do have a leg up just because we had to deal with infectious disease for a long period of time, and we’ve got some good methods.”

Throughout the turmoil, Yeske says communication with everyone involved was crucial. “It takes a lot of communication and support…to make sure everybody understood what the goal was. We spent a lot of time on the phone talking to a lot of people, and I think that’s what it takes through those types of things…to make sure everybody’s at least understanding what’s going on.”



Swine veterinarians award debt-relief scholarship to Henry Johnson

A Swine Vet Center veterinarian was awarded a debt-relief scholarship by the American Association of Swine Veterinarians (AASV) Foundation during its recent virtual annual meeting. The foundation awarded a $5,000 scholarship to Henry Johnson, DVM, with Swine Vet Center, St. Peter, Minnesota.

The AASV Foundation awarded three $5,000 scholarships to early-career swine practitioners through the “Dr. Conrad and Judy Schmidt Family Student Debt Relief Endowment.” The purpose of the scholarships is to help relieve the student debt of recent veterinary graduates engaged in swine practice who still have significant debt burden. Qualified applicants must have been engaged in private practice with at least 50% of their time devoted to swine, providing on-farm service directly to independent pork producers.

Johnson is a 2017 graduate of the University of Illinois College of Veterinary Medicine. He works with various sized family farms to better the health and production of their animals to ensure a safe and reliable food product for consumers. He strives to teach production staff how important they are in maximizing day-1 piglet care and identifying sick animals. He enjoys supporting students, providing the same mentorship he received through AASV, and fostering the next generation of swine veterinarians.



Highly infectious PRRS variant causes high mortalities on sow farms

A variant of the porcine reproductive and respiratory syndrome (PRRS) virus is taking a heavy toll on hog farms in southern Minnesota and northern Iowa. The variant, identified as PRRS 1-4-4, hits sow farms especially hard, causing 10% to 20% sow mortality and high mortalities in the nursery of 50% and even as high as 80%. In grow-finish units, mortalities are less but still can be significant, and growth rates drop dramatically.

“This PRRS virus hasn’t done anything we haven’t seen with PRRS; it’s just way more dramatic,” reported Paul Yeske, DVM, Swine Vet Center, St. Peter, Minnesota. Yeske talked about PRRS 1-4-4 as part of a webinar presented by the Swine Health Information Center and American Association of Swine Veterinarians.

Clinical signs

“From what we’ve seen on sow farms, this virus has a pretty distinct footprint,” Yeske explained. “You almost don’t have to wait for sequencing because you know what it looks like from the clinical signs.”

Symptoms include sows going off feed, abortions, increased sow mortality, increased piglet mortality, increased mummies and high post-weaning mortality.

“One thing that’s unique to this virus is it tends to move quickly through the herds once you see clinical signs,” he added. “You’ll start with four to five animals off feed and then 200 the next day and 300 the next. It marches through the herd quickly.

“The abortions start about the same time the animals go off feed. We’ve seen upwards of 3 to 5 weeks of production aborted and 10% to 20% of the sows dying in 2 to 3 weeks.

“Also, there’s high piglet mortality in the farrowing house…50% up to 80%, which I didn’t think was possible.”

In addition, neither vaccination nor prior exposure to the virus appears to reduce the outbreaks, he added, but it’s difficult to tell with the limited number of herds experiencing an outbreak.

High viremia

The PRRS 1-4-4 variant produces high levels of viremia, allowing it to spread easily in an area, Yeske explained. In addition, a milder winter with overcast, warm weather has helped the virus move around.

An increased number of diagnoses started in October 2020 in the two-state area, beginning with outbreaks in grow-finish sites and moving into sow farms.

“Certainly, the worst breaks have been, like we always see with PRRS, when you have viremic pigs leaving the sow farms,” he added. “But with this virus, we have lateral outbreaks even at the end of nursery with significant mortality.”

Yeske indicated some of the farms that broke were filtered, while others stayed negative even when located next to positive finishing sites and lots of positive pigs.

“Filters continue to show us they help but are not perfect,” he added. “The PRRS viral load is very high. There are lots of opportunities for this virus to get in, and if there’s a weakness, it’s likely going to find it.”

Stabilizing herds

After a 2- to 4-week period where herds experience the devastating losses, farms start to stabilize.

“We see sows start to return to normal,” Yeske said. “We see normal pigs born again but with very low, live born due to mummies, even though total born are still in the 16 to 17 pigs range. There are a lot of mummies on these farms but not necessarily all farms.”

As the herds continue to stabilize, Yeske said they will track them on the PRRS timeline to see if it runs similar to other strains they have dealt with in the past.

Review biosecurity

The big lesson Yeske hopes producers will learn from these outbreaks is the importance of a biosecurity plan that is strictly followed. He urges everyone to review their biosecurity.

“Identify the greatest area of risk in your herd,” he explained. “Risk is how likely something is to come into the herd and then how many times a week do you do that activity. Multiply those two to give you the risk.

“Then improve any weakness in your biosecurity system, and do it sooner rather than later,” he added. “Don’t wait to identify it in your outbreak investigation.”



Fine-tune nursery management to achieve optimal pig performance

By Kate Ayers
Better Pork


Meeting new people, trying new food, and exploring a new destination can be exciting but daunting experiences that we encounter. Now imagine combining all three experiences into one day.

It would be justifiable for anyone to feel apprehension about leaving the comforts of home for so much “newness.” Young pigs face new litter mates, feed and environments when they enter the nursery. These stimuli can be inherently overwhelming and stressful.

Fortunately, swine producers work hard to ensure the health of their herds and provide a smooth transition into the nursery.

Success in the nursery can be attributed to supporting the development of “bulletproof pigs that get off to a good start, have a lot of antibodies, and can handle the immune challenges that they face in the nursery. Piglets that have antibodies are often less susceptible to scours at farrowing and post-weaning in the barns,” says Dr. Laura Bruner, a veterinarian at

the Swine Vet Center in St. Peter, Minnesota.

“After weaning, we want the piglets to just focus on eating, not rotavirus, strep or any other diseases. We want them to hit the ground running. So, preparing for the nursery phase is important.”

This month, Better Pork speaks with Bruner, swine nutritionists, and other sector specialists to learn how pork producers can level up their nursery management skills and overcome pig health challenges during this critical production phase.

Before the nursery

Optimizing health and performance in the nursery begins in the farrowing room and, more specifically, originates from sow comfort and milk production.

“This process starts six weeks before the piglets are born. We get the sow ready to produce the highest amount of antibodies that she can and make sure she is in the right condition, so that when the piglets are born, they are set up for success,” Bruner says.

Colostrum antibodies help prepare the piglets for farrowing and then the transition into the nursery.

Once the piglets are born, “make sure sows are eating well and producing lots of milk to optimize piglet growth while they are still suckling,” says Dr. Lee-Anne Huber. She’s an assistant professor in the department of animal biosciences at the University of Guelph in Ontario. Her research focuses on swine nutrition.

Producers can help “piglets prepare for life without mom and the comforts of the farrowing crates,” says Dennis Robles, the production specialist for Swine Health Professionals in Steinbach, Man. The company helps producers develop herd health plans, monitor production progress, and maintain biosecurity targets.

For example, “exposure to small amounts of creep feed after their second week of life will help familiarize the piglets with the first-stage ration that they will get in the nursery,” says Dr. Tim Blackwell. He’s a lead veterinarian in the animal health and welfare branch of the Ontario Ministry of Agriculture, Food and Rural Affairs and is based in Elora, Ont.

Huber agrees that creep feed can help make nursery transition easier for piglets.

Producers can “offer a highly digestible and palatable diet to the piglets that only they can access. The young pigs can then learn how to eat away from the sow.

“Not all piglets will participate and, if they do, it does not always translate to heavier weaning weights. Typically, though, piglets that do eat creep feed will have higher feed intakes after weaning,” she says.

Indeed, “heavier pigs at weaning will reach market weight sooner than lighter pigs,” Huber says.

“An old rule of thumb is that if a piglet weighs 100 grams (3.5 ounces) heavier at weaning, it will reach market weight half to a full day sooner than lighter pigs. This fact motivates us to set up pigs with solid weaning weights.

“In addition to creep feeding, producers can provide piglets in the farrowing room with a water source, such as a cup or nipple drinker that is close to the floor. The drinker teaches piglets that feed and water don’t always come from the same place as it does when they suckle the sow. If you can teach them that aspect ahead of time, you’re already a step ahead,” Huber says.

Weaning age can also play a significant role in the well-being and success of piglets in the nursery.

“Wean age is huge. The older the pig, the better it handles stress of transitioning from farrowing to the nursery,” Bruner says. “And the better the pig takes off in the nursery.”

Traditionally, weaning age is 21 days, but shifting to 24 days, for example, can help piglets put on more weight and thrive in the nursery, says Dr. Crystal Levesque, an associate professor of swine nutrition at South Dakota State University.

In operations that require transportation to another farm location, staff members can help reduce weaning stress through gentle handling, “moving pigs in a calm manner, preventing overcrowding, and loading them into a clean, disinfected and dried or baked trailer,” Robles says.

Clean and chemical-free shavings are better for footing, and trailers should have appropriate covers to protect the pigs from outside conditions, he adds.

Before piglets enter the nursery barn, producers should take extra care ensuring that “the room has been adequately washed, disinfected and dried before a new group of weaned pigs arrives. Farmers should be attentive to the removal of organic materials on floors, walls, pen dividers, gates and pins, and other surfaces,” Robles says.

Producers must use “disinfectants according to manufacturers’ accurate dosages and allow enough time for the disinfectant to work effectively. Also, never underestimate the process of drying the room or barn to provide the new batch of pigs with a truly clean environment.”

As part of pen or barn preparation, temperature is also an important factor to consider. “A day before the pigs arrive, warm the room to the nursery entry temperature, which is between 29 and 31 C (84 and 88 F). This preparation will help them get off to a great start. Indeed, correct ventilation and environmental settings must be in place even before the first hoof steps into the barn,” Robles says.

Solid start

Newly weaned piglets may experience environmental, social, nutritional and physiological stressors during their transition to the nursery. As a result, producers should keep watchful eyes on their newcomers to identify piglets that may get off to a slow start.

“The first two to three days in the nursery are the most critical as the piglets adjust to a new environment,” Blackwell says.

Producers can use qualitative or quantitative measurements to monitor pig health and progress, he says.

“My favourite metric is feed intake. Depending on the weaning age, which is commonly around 21 days, I like to see 400 grams (14 ounces) of feed disappear per pig in the first 48 hours. A little bit more if you wean them later and a little bit less if you wean them earlier,” Blackwell says.

Studies show “that 85 per cent of newly weaned pigs take approximately 35 hours to find water and 90 per cent of them take 30 hours to find feed,” Robles says.

Indeed, some pigs may go without food for a substantial duration, Levesque says. “This length of time without anything going into the gut can increase risks of diarrhea, infections, coughs, or flu. It doesn’t take long for the gut to weaken,” she says.

To ensure that pigs consume enough feed and water as soon as possible after entering the nursery, farmers can use several tactics.

One approach is to wait a couple hours and allow the piglets to settle into their new home before feeding the pigs their first meal.

“When piglets are weaned from litters into bigger pens with multiple litters, there is an enormous amount of distractions for them. They investigate the pen and pen mates and figure out where the water and heat are located,” Blackwell says.

“There are just too many other distractions in those first two or three hours. If feed is already in the feeder, it gets stale and the pigs don’t key in on it because there are so many other things going on.”

Mat feeding can help piglets find feed and become more comfortable.

During “the first five to seven days in the nursery, this feeding strategy allows the pigs to sort through the feed. In farrowing, eating is a social event. So, if pen mates see pigs gathering in one spot, they’ll be curious and want to see what is going on,” Bruner says.

Pigs also become accustomed to a signal at feeding time.

“For the first few days, that signal could be a caretaker coming into the pen to deposit feed. Staff members can then more easily identify pigs that are laying down or not interested in the feed, and you can provide additional support to those pigs,” Blackwell says.

Farmers who closely monitor their herds can identify lighter or weaker pigs and provide the extra care they need to thrive.

“Curious and hungry pigs who ate creep feed will come up to the feeder pretty quickly. They will encourage other pigs to come up with them. This time is a good opportunity for producers to see which pigs do not come up to the feeder and to help them,” Blackwell says.

“If you have a group of lighter pigs, they should go in their own pen. You can keep an extra eye on those animals,” he says.

Feed types

The number 1 factor to get piglets off to a solid start in the nursery is to get them to eat, many experts say. To ensure that piglets consume adequate levels of nutrients, the feed must taste good and be fresh.

Typically, nursery diets are highly palatable with high inclusions of “animal proteins, such as fish meal or milk products, which help piglets transition from a milk-based diet to solid feed that is primarily made up of plant protein,” Huber says.

Producers must examine nutritional, feed and management factors in their operations and identify any gaps or areas that they can improve.

“After piglets are weaned, they often experience a post-weaning growth lag” from stress and changes in diet and the environment, Huber says. “They also have immature digestive tracts. Their stomachs are not as acidic as older pigs, and their digestive enzymes are not as active.

“If you can shorten that postweaning growth-lag period, pigs may reach a heavier weight sooner and could have higher exit weights,” she says.

“Producers can use feed additives to promote nutrient absorption and gut health development. Such products may include acidifiers, prebiotics, and exogenous enzymes. But definitely consult with your nutritionist before making any changes.”

Feeder hygiene and dispensing mechanisms are also important. Producers must ensure feed is fresh and not caked onto the feeder, Huber says. Increasing the frequency of feed delivery can also help stimulate intake.

In addition, “make sure feeder pan coverage is approximately 50 per cent,” Huber says.

“You don’t want the feeder pan to be overflowing because the excess feed could build up in the corners, but you also don’t want the feeder to be too scarce because you want feed to be present when the pigs go looking for it.”

More feeder space for each pig could help smaller and quieter pigs access feed without getting bullied out of the way, Blackwell’s research team recently found.

“An inch and a half to two inches (3.8 to 5.0 centimetres) of feeder space per pig will ensure they do not have restricted feed intake,” Blackwell says.

“One inch (2.5 cm) per pig may be adequate for the first two or three weeks after weaning, but for the next three or four weeks, when the pigs put on more weight, more feeder space is better. Adding another 50 per cent of feeder space costs between $0.05 and $0.10 per pig over the lifetime of the feeder. You easily get that back in added weight – particularly for the quieter and less aggressive pigs who don’t want to push their way in.”

Another strategy producers can use to reduce post-weaning lag growth and feed costs is to take advantage of compensatory growth, a recent study showed. “Healthy pigs can exhibit compensatory growth after a period of feeding them a less digestible diet, such as a corn- or soybean-based ration, instead of a diet with lots of animal protein,” Huber says.

“Their growth will slow down early in the nursery but then their growth accelerates, and they can achieve the same exit weight as piglets fed a conventional nursery diet. This approach can be a way to reduce feed costs in the nursery, too.”

Overcome nursery challenges

Hog producers can use technology and work with their teams to address issues and promote pig performance in nurseries.

“Always have an accurate data recording system and room monitoring datasheets that provide information on the number of pigs in the nursery, date of entry, age of animals, treatment provisions, mortality and incidence of disease,” Robles says.

Producers can also collect information on out-of-feed-or-water events, storms and power outages that pertain to each batch of pigs, he says.

Measure “entry weights of every batch of pigs. Have another weigh-in at the mid-nursery stage to know if they are growing according to the growth curves you expect and project.

“Your veterinarian, feed nutritionist or production specialist can help you understand reasons why the animals may not be growing as projected.

“On exit, knowing how the group performed throughout the nursery can help you compare and improve on subsequent batches you bring into the barn,” Robles says.

Indeed, nursery management is like a “Jenga puzzle. Every time you miss feedback, feed intake, or temperatures in the barns, for example, a block comes out of that Jenga tower,” Bruner says.

“It is crucial to make sure all the pieces are stacked properly” throughout this production stage.

As a result, perhaps the most important piece in the nursery production puzzle is to “maximize feed intake in those first two to three days after young pigs enter the nursery,” Blackwell says.

Overall, “every barn has its own set of challenges,” Robles says.

“But the universal truth about having great biosecurity to prevent entry of diseases, sourcing animals from a high-health-status herd and following herd veterinary guidelines are the main focus areas to work on” to mitigate challenges and promote optimal animal performance, Robles says.


View this article in Better Pork, February 2021.





Virulent PRRS outbreaks in grow-finish require fast action to cut losses

A particularly difficult variant of the porcine reproductive and respiratory syndrome (PRRS) virus recently hit hog farms in south-central Minnesota. Henry Johnson, DVM, with Swine Vet Center in St. Peter, Minnesota, was called to diagnose and treat the PRRS outbreaks on client farms.

The virus has been identified as PRRS 1-4-4 and, to date, is the most virulent PRRS variant to infect hogs in the US.

“More herds have gotten infected, and this PRRS strain seems to be extremely pathogenic and more prone to airborne transmission,” Johnson said.

When it affects grow-finish units, he recommends immediate and aggressive treatment to reduce mortalities.

First symptoms

“When you walk into a PRRS 1-4-4 outbreak, you see a lot of pigs with varying degrees of respiratory challenge,” Johnson explained. Often, he sees pigs “thumping,” where the animals labor to breathe through airways blocked by bacterial and viral pneumonias.

“Other times, pigs are very, very lethargic because PRRS attacks and disables the whole immune system in pigs,” he said.

An outbreak can be identified early if grow-finish units are tracking water consumption. Pigs will quit drinking first, causing a dramatic drop-off in water usage. This should signal the need to start intensive pig care immediately, Johnson noted.

These symptoms may affect 5% to 25% of the pigs, depending on where they are in the disease challenge.

Diagnose, separate sick pigs

Johnson’s first action is to gather samples and send them to a diagnostic lab. The PRRS virus strain needs to be verified, and secondary bacterial infections identified.

“Get good bacteriology and susceptibility information from the lab, so you can make better microbial decisions and have confidence that you are putting the right medication for the right bug and utilize it appropriately,” he said. “It’s also good, judicious antibiotic use.”

At the same time, he wants to be aggressive and get help started for ailing pigs. He recommends moving critically ill pigs to sick pens for individual care.

“The best thing to do is provide a warm, dry, comfortable area with less pressure and competition for feed, water and space,” Johnson said. “Pigs can recover and subsequently move back to the general population where they are mixed in with other pigs. Then you can cycle other pigs through that sick pen.”

Another immediate action should be to increase barn temperatures, especially for young pigs. Pigs rarely die from being too warm in the winter during the nursery phase but can die of complications from being too cold.

Suppress secondary bugs

“A lot of times with these nasty PRRS [outbreaks], you are already behind the eight ball when you start,” he said. “You will never cure viral disease with an antibiotic. You are just trying to suppress secondary bacterial infections and control them when the immune system is devastated and rebooting after going through the PRRS infection.”

Depending on the herd and challenge, Johnson said they will use different antibiotics and delivery methods. He recommends starting water medication right away to address common secondary bugs like Streptococcus Suis, Glasser’s disease, Mycoplasma hyopneumoniae and Pasteurella.

When pigs are unable to get up to drink, Johnson recommends a mass injection followed by oral antibiotics or water medications.

“A lot of focus for me is to make sure we use the right antibiotics and follow up with caregivers to make sure the pigs that need help are moved and getting the necessary care,” he said.

Even with these care regimens, mortalities can still be high. He estimates as much as 15% mortality can occur.

Biosecurity alert

“When you get a virus that is really severe like this and spreads quickly across multiple production systems and geographies, it is a wake-up call to biosecurity practices in grow-finish,” Johnson said.

If any labor or equipment is shared, make sure all parties involved know what is going on. It’s also good to keep the feed mill in the loop as well.

“It’s a hard culture to establish, but if you are able to reduce a break like this, it demonstrates the importance of keeping our barns clean,” he said.




Cost-cutting measures take the sting out of high feed prices

The last time pork producers worried about high feed costs was 2015. Now, higher commodity prices have producers revisiting strategies to reduce feed costs and preserve profits, according to Ryan Strobel, DVM, Swine Vet Center, St. Peter, Minnesota.

“Six months ago, we were sitting at $3 cash corn,” Strobel said. “Now it is over $5 cash corn. That’s about $20 per head difference in feed costs…and might take all our profits.” Every dollar increase in corn price is roughly $10 difference in cost per head.

Strobel offers three strategies to help reduce feed costs.

1. Reduce slaughter weights

“A quick, easy way to save on feed costs is to bring down slaughter weights,” he said. “If you are selling at weights of 280 to 300 pounds, back off to 270 to 275 pounds and save 10 to 25 pounds a hog.”

However, the ability to cut slaughter weights depends on the packer’s current kill situation, the grid at your packer and contracts. This option is not possible for everyone.

Another challenge for cutting pig weights is the quality of the 2020 corn crop. Strobel said pigs are gaining well on corn produced in southern Minnesota and northern Iowa in 2020. It can be a challenge to get weights under control. Plus, continued genetic improvement is making a difference. Pigs may be ahead of normal marketing windows.

2. Feeder settings

Other obvious ways to reduce feed costs is to make sure you aren’t wasting feed. “Recheck your feeder settings and make sure they are set at 30% to 40% pan coverage,” Strobel said. Feeders set too open will result in poor feed quality and feed wastage.

Check over feeders regularly for other problems that can lead to waste like moldy feed. Repair feed lines that have holes in them, cracked bin boots that can allow moldy feed and any cracks in feeders that can result in wastage.

Mat feeding in wean-to-finish also can lead to feed waste. Strobel recommends working with the staff to make sure they understand feed is expensive and shouldn’t be dumped in the pit.

“I still recommend mat feeding as much as possible, but smaller amounts more often will help the pigs continue to eat and not waste as much over the side of the mat,” he explained.

Sow farms should periodically weigh feed boxes to make sure the feed amounts are accurate. Also conduct body-condition checks more often to make sure sows aren’t eating too much and adding condition when they don’t need it.

3. Feed production issues

Make sure the feed mill is set so that particle size is below 700 microns, Strobel said. Coarse feed particles will cause poor feed efficiency and reduced nutrient utilization. It can also increase feed waste at the feeder. More consistent micron size really helps with settings as well as feed utilization. Check micron size at the mill at least once a week to make sure the rollers or hammer stay accurate.

Double-check your tandem bins to make sure the right diets are used at the right time for feed efficiency. For example, this means finishing the phase 3 diet before moving on to the phase 4 diet, he explained. Diets are specially formulated for specific weight ranges and genetics. Blending two diets will hurt performance and feed efficiency.

Some producers also may decide to replace soybean meal in pig diets to cut costs. Strobel said in the next 6 months, if soybean-meal prices continue to rise, he expects to see producers move to replacements like canola meal, bakery byproducts or distiller’s dried grains with solubles, depending on market prices of what can be added.