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The Top 10 Questions of Porcine Cirovirus

Despite the appreciable gains that circovirus vaccines have made in controlling porcine circovirus-associated disease (PCVAD), 10 major questions need answers to improve the understanding of this organism and the disease it spawns, says Robert Desrosiers, DVM, Boehringer Ingelheim Vetmedica (BIVI), Inc. of Canada.

Desrosiers spoke at the 2008 symposium on circovirus in San Diego, CA, sponsored by BIVI. Following are his comments:

  1. Where are we with agents XYZ? For various reasons, some researchers cling to the idea that an organism referred to as Agent X may be involved with PCVAD. Three disease agents, porcine parvovirus, porcine reproductive and respiratory syndrome and Mycoplasmal pneumonia, in conjunction with porcine circovirus type 2 (PCV2), have been shown to exacerbate PCVAD problems beyond an infection of PCV2 alone.

    There is no reason to believe, however, that those known swine pathogens are the extent of PCVAD co-infections. In fact, recent evidence suggests that the Torque Teno virus may possibly play a role in PCVAD. Activation of the immune system by certain vaccines or adjuvants has also been shown in certain situations to trigger PCVAD, suggesting agents XYZ could play a role.

    While the possibility remains of new agents being associated with PCVAD, extensive research shows that quite simply, when PCV2 is controlled, the disease and related losses are also eliminated.

  2. Can virulence vary between PCV2 isolates? The evidence appears quite contradictory around the world, and regardless, it does not seem to fully explain the explosion of PCVAD problems in the last decade.

  3. Is it possible to have PCV2-associated losses without having clinical signs? This is an important question since nearly all swine herds are infected with PCV2, yet not all herds appear to suffer losses from this pathogen. Field trials suggest there are situations where the PCV2 virus may have contributed to performance losses, but without being recognized as such. In one case, pigs vaccinated with a one-dose vaccine, Ingelvac CircoFLEX, were about 6 lb. heavier at the end of the study and had 5% less mortality than control pigs.

  4. Can PCV2 be transmitted by boar semen? Studies of hundreds of cases in foreign countries discount the role of semen in the spread of PCVAD. Infectious PCV2 can be found in semen; in commercial boar studs, it is common to detect PCV2 in semen samples by polymerase chain reaction (PCR). However, in one study where naïve gilts were inseminated with semen containing infectious PCV2, they didn't get infected.

    Still, more work is probably needed before semen can be removed from the list of potentially relevant factors in the epidemiology of PCV2.

  5. Is PCV2 the cause of porcine dermatitis and nephropathy syndrome (PDNS)? While there has been a multitude of experimental infections with this organism around the world, none has provided conclusive evidence that it could cause PDNS.

    However, there appears to be some links based on reports on PCV2 and PDNS in a number of countries. And in many farms where PDNS was present, it virtually disappeared following the use of PCV2 vaccines in piglets.

  6. How important is it for PCV2 vaccines to produce antibodies? Unlike some vaccines, it appears that there is no correlation between antibody production and protection for PCV2 vaccines. In a Quebec study using Ingelvac CircoFLEX, pigs vaccinated between 19 and 59 days of age had almost four times lower mortality than control group pigs. Yet in serological tests, none of the pigs vaccinated at 26 days of age had seroconverted or shown antibody titers to PCV2 by Day 30. Similar results have been found in U.S. studies with circovirus vaccines.

    The end result is that some PCV2 vaccines can induce excellent protection in field situations, even when they do not produce a strong antibody response as measured by serological tests following vaccination.

  7. Can very young pigs be effectively vaccinated in the presence of maternal immunity? Because baby pigs are handled at processing time, many producers and veterinarians express an interest in vaccinating against PCV2 at an early age. Two key questions arise: Can vaccination overcome maternal immunity, and will immunity last until pigs are marketed?

    While it appears to be both convenient and successful in some situations, it may not always produce satisfactory results. Accordingly, caution is needed before making changes in vaccination timing, particularly when the current program has already been successful.

  8. How do current vaccines compare in terms of efficacy and safety? Three PCV2 vaccines have been available in Canada: a vaccine licensed for use in gilts and sows (Merial), a two-dose vaccine for use in pigs (Intervet) and a one-dose vaccine for pigs (Ingelvac CircoFLEX).

    Overall results showed pigs born from vaccinated sows had mortality results similar to pigs born from non-vaccinated sows. Also, the two-dose and one-dose pig vaccines produced superior results. In safety trials conducted at Iowa State University, Ingelvac CircoFLEX produced significantly fewer lesions 14 days after vaccination than the two other vaccines.

  9. Should we vaccinate gilts and sows? The gilt/sow vaccine (Merial) was the first PCV2 vaccine available in Canada, and many herds used it. The consensus is that in many cases, it did not produce the results that were expected. When problems were occurring in the nursery, these problems were often delayed and transferred to the finishing unit. Inconsistent results led to most producers not relying solely on gilt/sow vaccination to protect their herds. PCV2 appears to rarely affect reproductive performance.

  10. Will vaccination for PCV2 continue forever? Stopping vaccination now would seem risky. Those interested in trying should start small and vaccinate only one half of one barn. That way, if losses occur in non-vaccinates, they will be limited to a relatively small number of animals.

European countries have seen a decline in PCVAD, despite the fact that vaccine wasn't available until years after the outbreaks began. In North America, it is believed that herds suffered losses due to PCV2 before the epizootic of PCVAD.

In some cases, PCV2 vaccines have raised the performance to levels that are better than they were before the PCVAD outbreaks. And in other herds, with no apparent clinical signs of PCVAD, vaccination still seems to produce a benefit. So, for now, vaccination remains a vital cog in herd health programs on many farms.

Preparing for FMD

Getting the word out about foot-and-mouth disease (FMD) will help the United States better prepare for the potential disease disaster.

Even with the best emergency disease preparedness plans, foreign animal disease outbreaks still occur. That's why the U.S. Department of Agriculture (USDA) decided to team up with its commodity industry partners last month to stage an FMD media day at its Animal and Plant Health Inspection Service (APHIS) offices at Riverdale, MD.

Forging closer ties will enhance effective disease prevention strategies, says John Clifford, DVM, deputy administrator for APHIS' Veterinary Services.

APHIS has been working behind the scenes with livestock and dairy stakeholder groups since 2001 in defining and refining its emergency response plans for FMD. But officials from both sides came to the realization that a program needs to be effectively communicated to succeed.

“We rely on you to help the public understand and relay technical information to them. Good communication helps all of us: helping explain to producers what to do during a disease emergency, and helping the public and our trading partners understand that this disease can affect the health of our nation's herd and export of our products,” Clifford adds.

APHIS has learned firsthand about the public's needs for simple explanations of complex animal disease information. A good example is the bovine spongiform encephalopathy (BSE) situation. The federal agency found that explaining the cause of the disease was very complicated. APHIS fielded about 10,000 calls over the last half-dozen years, says Ed Curlett, APHIS director of Public Affairs. Still, today about 20% of consumers surveyed confuse BSE with FMD. BSE, or Mad Cow Disease, is a chronic, brain-wasting disease found mainly in cattle and sheep.

In contrast, FMD is much more pervasive and devastating, says Jose Diez, DVM, associate deputy administrator for APHIS' Emergency Management and Diagnostics. The virus affects all cloven-hoofed animals.

“The virus is excreted in very large amounts, and it only takes a small amount to infect animals. It also has a short incubation period, as little as 3-5 days. If left unchecked, an FMD break in the United States would spread very rapidly and cost the country billions and billions of dollars,” he says.

For example, the FMD outbreak in the United Kingdom affected about 10 million animals at an estimated cost of $17.4 billion. The small FMD break there in 2007 cost $20 million/week.

California Study of FMD

APHIS and the California Department of Food and Agriculture conducted a study involving a “mock outbreak” of FMD in the state's large dairy industry, says Diez. Accumulating the cost of eradication, production losses and trade restrictions, APHIS pegged the direct cost of the disease at up to $4.8 billion. Losses to packers and processors were up to $2.6 billion. And trade losses could be up to $6 billion, because countries would stop purchases the moment FMD was identified, and products could only be sold to countries that currently have FMD.

“Because the disease occurs in about two-thirds of the world, there is always a chance of an accidental or intentional introduction,” Diez stresses. Many countries have learned to live with FMD, but USDA's policy is to stamp it out.

APHIS officials agree that even though the United States has been free of FMD since 1929, it would be a big mistake to assume a false sense of security.

To minimize the risk of FMD, the United States relies on its import regulations, point-of-entry surveillance, customs and border inspections and trade restrictions with FMD-affected nations.

Foreign Animal Disease Investigations

APHIS also conducts an average of 400 foreign animal disease investigations annually in the United States, mainly looking for vesicular-type lesions that could mimic FMD, says Jon Zack, DVM, Preparedness and Incident coordinator for APHIS' Emergency Management and Diagnostics. Last year, there were about 245 vesicular disease investigations.

For the swine industry, vesicular stomatitis, which sporadically affects livestock and horses in the western United States, appears somewhat similar to FMD. The FMD virus produces vesicles in the mouth, hooves, on the udder and teats.

Zack observes: “FMD is unique in that it is the most highly contagious disease in cloven-hoofed animals. FMD is not contagious to humans. All secretions are contagious, and the virus may be present in milk and semen for up to four days before clinical signs are seen. The virus infects susceptible animals orally, especially swine, and by respiratory tract, especially cattle.” Cattle express high susceptibility to the virus and readily react to it.

“Pigs are the amplifiers; if they get FMD, then they can replicate it and release air from their lungs through their nose and mouth into the air, and actually create a plume of virus that can spread down the road, depending on weather conditions,” he states.

Sheep tend not to show as significant lesions when infected with FMD, posing an unknown threat of disease spread when moved interstate.

“For FMD, it is clear that it is a devastating disease production-wise, but it is not one of those diseases that causes severe mortality in adult animals. Death rate is more common in young stock suffering from myocarditis (heart lesions) or failure to thrive from mouth lesions,” Zack says.

The other bad thing about FMD is the virus features seven serotypes and about 60 subtypes, he says. The problem is that current FMD vaccines don't cover all of the serotypes.

“The USDA and Department of Homeland Security are working hard to develop the next generation of FMD vaccines, which will be highly effective, provide rapid onset of immunity, stop virus shedding, and are effective against multiple serotypes.” Currently, FMD vaccines do not protect against multiple serotypes and subtypes.

Disease Investigation Process

Basically, if a producer or herd veterinarian notices an unusual condition, such as blisters on the nose, mouth or feet of animals in his herd, the swine veterinarian or state veterinarian will inspect the suspect animals on the farm. If clinical signs are identified, then a call is placed to federal or state animal health officials, triggering a foreign animal disease investigation, explains Zack.

In turn, a state or federally employed veterinarian specially trained to investigate foreign animal diseases will visit the farm and send appropriate samples to the Plum Island (NY) foreign animal disease diagnostic laboratory.

At Plum Island, various rapid tests will deliver presumptive or preliminary results in 4-8 hours. A series of confirmatory tests yield results in 24-48 hours. The gold standard — virus isolation — can take up to a week to complete.

Media's Role

Should FMD strike this country, the media would play an important role in disseminating the correct information and avoiding the panic that an accidental or intentional introduction of FMD could bring, Zack explains.

Dairy, beef and hog industry representatives of a cross-species working group on FMD reported on their activities at the FMD media day.

From a communications standpoint, the goal of the National Pork Board's efforts on FMD is to help pork producers with planning and preparedness, says Cindy Cunningham, assistant vice president of communications. “We want to keep our herds clean, but also know how to deal with an outbreak as quickly as possible, and that we are learning every step of the way how to be prepared for FMD.”

The Pork Board wants to maintain confidence in the pork supply, and at the same time ensure that pork producers receive accurate information on what they would need to do at the farm level in the event of an FMD outbreak.

The Pork Board is taking a very proactive stance and is committed to making sure its plan and preparedness are adequate, including allocating funding in the 2008 budget, Cunningham says.

Game Plan for FMD

Patrick Webb, DVM, director of swine health programs for the National Pork Board, and emergency management consultant Bruce Spence demonstrated their tabletop model depicting the flow of a mock FMD outbreak in a small area of northwest Iowa.

Webb explained how the identification of an infected premise quickly progresses to the development of zones for control and cleanup of an outbreak and a surveillance zone to protect the community at large.

The pair outlined the resources that must be marshaled in order to meet projections of completing the cleanup effort in one week.

Webb made it clear that major hog states like Iowa and North Carolina will implement different game plans in the event of an FMD outbreak. North Carolina has a half-dozen producers controlling the majority of pigs produced in a few major counties in the state, while Iowa's hog population is dispersed and still mainly controlled by a large number of independent producers. Iowa averages 40,000 hogs crossing its borders every day.

However, all that commerce stops if FMD hits. “So in all of our industries today, the faster we can get this (disease) quarantined or this area under control and provide assurances,” the faster things can return to normal, Webb says.

For additional information on foreign animal disease threats, see “Foreign Animal Disease Preparedness is the Key,” April 15, 2007. Also available from that Blueprint edition is a wall poster, “Be Prepared for Foreign Animal Diseases,” which features photos of typical clinical signs of Classical Swine Fever, African Swine Fever and the vesicular diseases, including FMD. Copies of the poster are available through the Pork Checkoff Call Center: 800-456-7675; ask for publication number 048072.

Rapid Test Developed for FMD

Arapid, on-farm test for foot-and-mouth disease (FMD) is now available commercially.

Nigel Ferris of the Institute for Animal Health's Pirbright Laboratory in England has been collaborating with Svanova Biotech AB (Sweden) since 2002 to develop the test, which was launched in April.

The small, hand-held “lateral flow” device employs the same technology that is used in home pregnancy tests. An extract of a small sample of tissue taken from an animal suspected of having FMD is spotted on the bottom of the device. This then flows up the device, and if FMD virus is present in the sample, a line forms within 10 minutes.

The test is easily performed on farms, meaning that a result can be obtained faster than sending a sample to the laboratory, and appropriate action taken much sooner.

The effort has been supported by England's Department of the Environment, Food and Rural Affairs, in collaboration with the European Union's LAB-ON-SITE project,

“In effect, we are taking the laboratory to the farm, for on-the-spot testing to support clinical diagnosis,” Ferris says.

Circovirus Vaccines Score Well

Swine veterinarian Steve Henry outlines the growing relevance of the three federally licensed porcine circovirus vaccines.

As one of the leaders of the Kansas State University (KSU) team assembled to help reduce the devastating impact of porcine circovirus type 2 (PCV2) in the state's hog operations, Steve Henry, DVM, Abilene, KS, is starting to admire the way the vaccines are performing.

The multidisciplinary team conducted a series of vaccine field trials from 2005-2007, when the disease first wreaked havoc on some northern Kansas herds. All three products were shown to significantly reduce mortality rates.

But the major improvement in growth rates was a pleasant surprise, he says.

In 2006, an initial study of a 300-sow herd negative for porcine reproductive and respiratory syndrome (PRRS), suffered from greatly elevated finishing mortalities due to PCV2.

Four finisher groups were tested, each housed as commingled vaccinates and control pigs in hoop barns. Pigs were vaccinated with two doses of circovirus vaccine (Intervet) at 3 and 6 weeks of age. Mortality was markedly reduced, from 17% in controls to 6% in vaccinates.

“Most striking and unexpected was the magnitude of the growth improvement in vaccinates vs. controls,” Henry remarked in a talk during the American Association of Swine Veterinarians annual meeting in March in San Diego, CA. “Vaccinates weighed 20 lb. more at market, a 6.8% advantage over controls. Finishing weights were 297 lb. for the vaccinates vs. 278 lb. for the controls.” (See Figure 1.)

But most importantly, weight distribution within treatment groups was much more equalized, including minimizing lightweight pigs. “Even the best pigs, those we thought were growing normally, were improved,” he says.

“In 35 years of practicing swine veterinary medicine, I have never seen any product inserted in pigs that would give you that kind of response and such a phenomenal shift in population distribution,” he declares.

From these results, it became apparent that vaccination impacted virus load and antibody response. “Even in the face of constant viral challenge in the commingled barns, vaccination resulted in a 10-fold reduction in virus load compared to controls,” Henry reports. “This vaccine-induced rise in antibody titer level was sustained throughout the study period.”

Second Vaccine Trial

A second field trial compared Fort Dodge Laboratories' single dose circovirus vaccine given at 4 weeks of age with Intervet's two-dose product at 4 and 6 weeks of age and a control group.

Henry suggests both vaccines equally reduced mortality, with a slight weight gain advantage for the two-dose vaccinated pigs.

As with the previous study, a shift in the distribution of weights occurred at 160 days of age, “clearly demonstrating the positive influence of porcine circovirus immunization on the entire group. Again, this improvement was noted in all pigs in the population, including the fast-growing pigs without any evidence of clinical porcine circovirus-associated disease (PCVAD),” he points out.

The across-the-board improvement in growth response from circovirus vaccination strongly suggests that performance losses due to the infection have been grossly understated, Henry states.

Genetic Differences

In the spring of 2006, a genetic multiplier contracted PCVAD, producing unthrifty finishing pigs. The herd was negative for PRRS and Mycoplasmal pneumonia.

The herd contained a Duroc-based line and a synthetic line comprised of Duroc, Pietrain and Large White genetics. Genetic line production and crosses were evaluated. Pigs were vaccinated with two doses at 3 and 5 weeks of age (Intervet), and commingled with control group pigs.

All of the lines showed significant improvement in growth rates. However, the rate of improvement was dramatically different between the genetic lines, Henry says. At 150 days of age, the Duroc-line vaccinated group showed a 10% increase in growth to 221 lb., compared to 201 lb. for the Duroc-line control pigs. However, vaccinated pigs were only 5 lb. heavier than unvaccinated controls for the synthetic line. The crosses were intermediate, with an 8-lb. difference in weight between vaccinated and unvaccinated pigs.

“This study supports the clinical impression that there are host genetic response differences in pigs immunized against porcine circovirus type 2 (PCV2), and it also lends credibility to the oft-mentioned belief from the field that some genetic lines seem to be more affected during PCVAD outbreaks,” he comments.

Passive Immunity

The KSU PCV2 team conducted a number of trials to assess the role passive maternal protection might play in limiting effective immunization.

In one trial, full or half doses of a two-dose regimen vaccine (Intervet) were given to 7- and 21-day-old pigs or to 21- and 35-day-old pigs.

Results showed the full dose of vaccine at 21 and 35 days of age protected 93% of vaccinates. Half doses of vaccine at 21 and 35 days of age protected 76% of vaccinates.

In younger pigs vaccinated at 7 and 21 days of age, the full and half dose vaccine protection was 70% and 65%, respectively. Passive antibody titers appeared to interfere with a post-vaccination antibody response, and many of these pigs became infected later in the growing period, Henry says.

Another trial compared Intervet, Fort Dodge and Boehringer Ingelheim circovirus vaccines in a farm severely affected with the disease. Vaccines again apparently failed to induce an antibody response in the face of high passive titers. The two-dose product afforded greater antibody production than the one-dose products, he says.

“Maternal passive antibody levels are important in the effort to predictably and effectively immunize as many animals as possible,” Henry states.

Virus Elimination Study

Studies suggest that immunization greatly decreases viral load. A collaborative study at KSU and Michigan State University immunized pig flows on the respective research farms.

Both are closed, batch production, high-health systems with excellent sanitation programs, providing a good framework to examine the potential for virus elimination, according to Henry.

The ability to derive PCV2-negative pigs from positive breeding herds was demonstrated prior to the availability of vaccines through selection based on maternal antibody, followed by isolation.

Future Work

The KSU team, Iowa State University and South Dakota State University have joined forces utilizing funding from the National Pork Board to develop antibody tests to objectively assess immunization efficiency.

“These results will help pave the way for next-generation vaccine development,” asserts Henry.

Fighting PRRS Still Causes Plenty of Pain

A PRRS break and high production costs can destroy an operation.

I have been in veterinary practice more than 20 years. I saw my first case of porcine reproductive and respiratory syndrome (PRRS) in 1997. It is a disease that has caused heartache and significant financial losses for a long time.

We have learned much about the virus in terms of how it is spread, and how to adjust our biosecurity protocols to keep it out. We have gone from not believing it can spread via aerosol methods to thinking it may be the most significant mode of transmission.

We have the technology to genetically sequence the virus and compare the different viruses isolated to see if they are related.

We have both modified live and killed vaccines to help stimulate immunity. We have sophisticated acclimation protocols to insure replacement animals are being exposed to the specific strain of virus in a herd.

We know how to eradicate the virus from a herd and produce negative pigs — only to see the farm break again.

Veterinarians and diagnostic labs have collaborated to geographically map where specific strains of virus are located in order to attempt area control.

With all this said, PRRS continues to be the most significant disease affecting North American pig production today.

When PRRS enters a herd, it can cause such large financial losses that many farms are unable to survive — especially with the large increase in the cost of production.

Case Study No. 1

A 3,200-sow farm with off-site nurseries and finishers has been PRRS positive but is producing PRRS-negative pigs for 18 months. These pigs stayed negative through finishing.

In November 2007, nursery death loss increased. Diagnostics from clinically affected pigs identified PRRS. Within two weeks, we saw clinical signs in the sow barn. Early farrowings had weak pigs, abortions and many sows off feed. We isolated the PRRS virus here as well. When we compared the virus from the nursery to the virus from the sow farm, it was found to be the same virus.

However, this virus was significantly different from any PRRS virus strain previously isolated. We also compared the virus to a large finishing farm less than five miles away without finding any similarities between the two viruses.

This virus caused a large amount of damage. Decreased production and increased costs from this outbreak conservatively raised the cost of production on this sow farm by $5/pig. The added costs in the nursery to finisher phase will easily be $5-$10/pig.

These types of losses are devastating and can't be survived long term.

Case Study No. 2

This 1,500-sow farm has been PRRS positive for many years. Minor flare-ups have occurred, but for the most part have been manageable. With each flare-up we would identify and sequence the virus and find it similar to the previous virus.

However, last fall the clinical disease was much more severe than before, and we isolated a virus that had a considerably different genetic sequence. This is a relatively new sequence that has been showing up across southern Minnesota and northern Iowa. We are cooperating with other veterinarians and the University of Minnesota to evaluate the different geographic areas where this virus has been identified.

To date there has been no clear indication as to where this new PRRS virus originated, or how it was spread.

We have tried intervention techniques to stabilize the sow herd. These efforts have shown good progress, but we still see an occasional problem that is frustrating and costly to deal with.


PRRS transmission studies have shown that contaminated needles, hands, transport trailers, insects, boar semen, shipping boxes and about anything you can possibly imagine as a physical means of transfer of PRRS virus can be a potential source for new virus introduction.

Biosecurity protocols can be put into place to prevent the actual mechanical introduction of the virus into the sow herd.

The one area that has not been widely implemented is the use of virus filters for a barn's incoming air. These filters have been used with success in boar studs, and some sow farms are starting to install them. It appears that a PRRS-negative sow farm in a densely populated area has a difficult time staying negative. There is hope that the filters may keep the virus out of the sow herds. They are expensive — but not as expensive as a PRRS outbreak.

The pork industry needs to work together to continue to look for innovative approaches to controlling and eliminating this costly disease.

Sow Lameness Underrated

A first-ever conference, which focused on sow lameness, served as a forum for changing attitudes and taking action to improve performance and animal welfare.

The latest chart from a USDA survey on swine health depicting sow lameness in the United States (Figure 1) indicates that lameness represents 15.2% of the reasons why pork producers cull sows.

“But our farm surveys today show the number of lame sows is far greater. Many sows culled for other reasons than lameness are also lame,” comments Mark Wilson, reproductive physiologist, Zinpro Performance Minerals at Zinpro's Feet First Symposium in Minneapolis.

Lame sows often go unrecognized and remain in the herd longer today because artificial insemination (AI) requires less structural soundness for breeding than the rigors of natural mating, says Wilson.

“Lameness is the biggest predictor of sow performance. The prevalence is quite high in sow barns,” says John Deen, DVM, University of Minnesota. He estimates that 80-90% of sows have some sort of claw lesions that are not being addressed.

These problems are ignored because of apathy, lack of education/training and a general reluctance to deal with them at the production level, Deen says.

Lameness is unmeasured and underestimated, says Deen, who adds that not all sows with lesions exhibit signs of lameness. That's partly due to the fact that lame sows have been shown to exhibit guarding behavior, says Deen. In other words, they may be experiencing painful or mechanical difficulties, but exhibit normal behavior to avoid detection.

Regardless, compromised sows will be challenged by a number of factors that affect their welfare: painful movement that exacerbates lameness the more they move, resulting in reduced feed intake; socialization issues; and poor reproductive behavior.

Increased levels of lameness add to staff workload in terms of treatment and euthanasia duties, extra time spent moving sows and picking replacement stock. Because treatment options are relatively few, frustration sets in, Deen says.

Minnesota Lameness Study

In a prospective study of sow lameness reported by Deen, 700 sows in a commercial herd in Minnesota were observed for one year. Sows were examined for lameness at entry into the farrowing crate, then researchers followed their productivity and longevity after weaning.

“The results were more marked than we expected,” he says. The 21% of sows identified as lame produced 0.02 less pigs/sow space/day and had an 18% greater likelihood of being removed, and these removals occurred much earlier. Also, these removals were more likely due to euthanasia or mortality.

The Minnesota research team estimated the economic impact of lameness at entry into the farrowing crate at about $180/sow. This figure is based on lower productivity, higher replacement costs and lower salvage values. It excludes the potential effects on preweaning mortality and the added pressures on the farm workers.

Claw Health

Prevention and early treatment of lameness and claw injuries are the best ways to help maintain feed consumption and appetite — and stave off early culling, Wilson notes.

Deen says their studies bear out the link between claw quality and lameness. Claw lesions are seen in 90% of cull sows.

Claw health needs to be improved and the following steps should be evaluated:

  • Measurement methods are needed for proper evaluation and intervention success.

  • Analgesia: the use of pain medications should be considered not only for the effects on the sows, but on subsequent productivity.

  • The Value of Trace Minerals

    Nutrition: Lactating sows are in extreme need of optimum nutrition to perform and reduce lameness problems.

  • Genotype: Conformational aspects need to be studied in more detail, particularly the relationship with specific claw lesions.

  • Flooring obviously can exacerbate the expression of lameness and contribute to the development of lesions.

  • Housing: Aggressive behavior appears to lead to more lesions and should be recognized as a factor in the development of lameness.

At the University of Minnesota Southern Research and Outreach Center at Waseca, Deen reports a much higher incidence of claw lesions have been observed in pens than in stalls. “It's going to be a challenge as we make the switch from stalls to pens,” he says.

A pyramid of factors (Figure 2), affect the development of lameness — not just one issue, Wilson expresses.

Economic Losses

It is suggested that zinc improves claw integrity. Wilson reports that several studies have shown that cows fed more available forms of zinc, manganese, copper and cobalt from Zinpro Performance Minerals led to reduced claw lesions and improved foot integrity, he says.

“Given the similarity in production environments and productivity expectations between cows and sows, it is logical that this response is likely for the sow also,” Wilson notes.

‘Feet First’ Symposium is Staged

In Denmark, there has been a dramatic increase in sow mortality over the last 15 years, reports Hans Aae, head of nutrition at Vitfoss in Denmark.

“The big reason is farmers are fined very heavily if they deliver lame sows to slaughter,” he says. “Sows are killed because 70% have locomotion or claw lesion problems.” Only 20% of sows reach the sixth parity.

Because there are restrictions on use of copper and zinc in the European Union, the option was to try trace minerals from Zinpro, says Aae. Combination organic performance minerals including copper, zinc and manganese were tested on two Danish hog farms. Today more than 100 farms are on this program. The use of trace minerals has cut sow mortality rates on these farms by more than half.

“I strongly believe that the use of organic trace minerals plays a role in improving sow longevity,” Aae says. “Producers face low hog prices in Denmark, but none of them have dropped this program.”

Economic Losses

In the end, clusters of lame sows drag down productivity while they are in the herd. Because they spend less time in the herd, replacement costs are higher and space utilization is lower due to higher turnover rate, says Deen.

Finally, don't underestimate the impact of lameness on product demand. “The largest recall of meat products in the history of the United States was due to lameness in cattle, and we should be concerned about the same in swine,” he stresses.

‘Feet First’ Symposium is Staged

The swine industry's first-ever symposium on sow lameness provided the approximately 150 attendees from around the world an educational look at an often-underestimated problem in hog operations.

The sessions were held in early April in Minneapolis and at the University of Minnesota, hosted by Zinpro Corp., based in Eden Prairie, MN. The members of the Feet First team, comprised of a global collection of researchers, veterinarians and nutritionists, are focused on identifying and preventing lameness in sows.

“Lameness in commercial sow operations is a much bigger issue than most operators realize, and it costs the industry an untold amount of income through lost performance and production each year,” says Terry Ward, director of Research and Nutritional Services, Zinpro Corp. “By taking proactive steps to identify and address lameness-causing factors, we can reduce the prevalence of lameness for the good of the animal and the business enterprise.”

Talks at the conference focused on performance and economics, lesion surveys, lesion identification and pathology, claw trimming for weight balance, effects on reproduction and the role of nutrition in foot health.

Workshops were also held at the University of Minnesota's Veterinary Medicine Center in St. Paul, where attendees participated in hands-on exercises and heard discussions on locomotion scoring and lesion identification. Attendees also learned the proper method for functional trimming using the Feet First chute.

Learn more about trace mineral nutrition from Zinpro by visiting or calling 800-445-6145.

Lesion Surveys Around the World

Lesions/disorders data were collected from independent surveys conducted from 2005 to 2008 in sow units in Australia, Germany, the Netherlands and the United States. Different individuals scored the lesions in the respective surveys.

Netherlands veterinarian Marrina Schuttert reported the data at the Zinpro Feet First Symposium in Minneapolis.

In Australia, 186 sows were scored in parities 0-10 in a 1,600-sow unit. Rear and front feet were scored within the first 60 days of gestation. Sows were in stalls for the first six weeks of gestation, then group-housed.

Results showed that the prevalence of claw lesions associated with the heel, sole and white line exceeded 90%. Severe heel overgrowth and erosion, severe lesions at the heel sole junction and severe white line lesions were recorded in about 30% of the feet. Vertical wall cracks were seen in about 80% of the feet.

In Germany, 76 sows were scored from a 400-sow herd representing parities 1-12. Gestating sows were kept in pens.

Results showed that heel overgrowth/erosion was the most common lesion, affecting more than 80% of feet. Other heel lesions were moderate or severe. Lesions at the heel/sole junction and white line represented 30% of feet surveyed.

Data was collected from 4,252 sows, parities 1-6, from various farms in the Netherlands. Gestating sows were housed in either stalls or pens.

The two most prevalent disorders in Dutch herds were heel overgrowth/erosion and elongated dew claws.

A U.S. operation in the Midwest involved scoring 771 sows in parities 0-10. Gestating sows were kept in stalls or pens.

More than 90% of all sows had a lesion in the wall and heel. About 50% to 75% of the sows had overgrown heels, lesions in the white line, heel/sole junction and sole. Heel lesions and overgrown heels were more prevalent in rear feet. Serious and deep lesions in the wall were observed in about half of the sows and in the heel in one of three sows. A quarter of the sows had serious and deep overgrown heels and serious and deep white line lesions.

Heel overgrowth/erosion was the most common claw disorder across all herds. Wall cracks were more common in herds in Australia and the United States, where most gestating sows are housed in stalls, vs. Dutch and German herds, where most gestating sows are housed in pens. Lesions were more common in the outer vs. the inner claw.

Crop Forecasts Rattle the Market

What a week for U.S. agriculture, in general, and the hog business in particular! Consider:

  • USDA issues its latest “Don’t Worry, Be Happy!” crop reports amid what is developing as the greatest flood in history.

  • Corn prices respond to both pieces of news with record highs. Omaha cash corn, which went above $6/bu. for the first time last week, was quoted at $6.70-$6.80 on Thursday. Chicago Mercantile Exchange (CME) Group corn futures for December gained $0.62/bu. from last Friday to stand at a record high of $7.395/bu. at Thursday’s close.

  • U.S. pork exports for April were nearly twice as large as they were one year ago, leaving year-to-date exports 52% larger than last year.

  • April pork exports accounted for over 21% of April U.S. pork production.
Let’s begin with the USDA’s May Crop Production report and World Supply and Demand Estimates. Table 1 shows USDA’s corn balance sheet based on these reports, which were released Tuesday. To their credit, USDA did lower their forecasted corn yield by 5 bu./acre in this report. It is very unusual for them to do that as early as June, since they have no information about actual plant populations, ear numbers, etc. The lateness of this planting season, though, dictated an early reduction in the forecast.

My criticism of the report is that USDA continues to forecast corn usage at levels that I believe are too low at their forecasted prices. USDA again reduced projected feed usage, this time to 5.150 billion bushels. Allowing for the DDGS from 1 billion more bushels used for ethanol, this feed usage level still amounts to a feed use reduction of 8.9%. To get that kind of reduction in feed usage, we will have to have prices much higher than USDA’s $5.30 - $6.30. This week’s futures market is making that point in spades.

Ethanol plants will operate full as long as they can cover variable costs. There will be enough capacity to use far more than 4 billion bushels of corn next year. Crude oil futures at $137/barrel imply higher gasoline prices and higher values for ethanol in the future, but last week’s drop in ethanol prices (to $2.33/gal. in Iowa) and the increase in corn prices are likely to put some plants near the point where they are not covering variable costs.

If that is a lasting situation, USDA may be okay with their 4 billion bushel usage for ethanol in the ’08-’09 crop year. If ethanol prices follow gasoline and oil upward, however, I fear that the ethanol number in Figure 1 is too low as well.

That brings us to exports. USDA reduced projected exports again this month, to just 2 billion bushels, 18% lower than last year. Higher world feed grain and, especially, wheat production is the main supporting factors for that change. The low dollar and the fact that U.S. corn is still a very good buy for many export customers argue against the decline. Given our customers’ proven record of “buying early” to secure supplies, I fear this number is too low as well.

Breakevens Ascend
And the only way to get these numbers lower is to drive corn prices higher. As I pointed out above, CME Group corn futures started that process this week, and I know of no one who really wants to venture where the process will end. With new-crop futures at $7.39 on Thursday, $8 is not at all out of the question, depending on how crop conditions develop over the next few weeks.

And what of hog feed costs? Figure 2 shows that my index of feed costs rose by about $40/ton from June 2 to June 12. I had to add $50 to the vertical axis just to fit in the most recent observations. These feed prices have driven my breakeven cost estimates for next summer to roughly $95/cwt. carcass. Who would have ever thought that June 2009 Lean Hogs futures at $91 would not be profitable?

The big factor in the grain markets is still weather. The flood (and perhaps more importantly, the cool, wet conditions that caused it) has certainly taken the shine off of this year’s crop prospects. USDA did not change its acreage forecasts in this week’s report, but virtually everyone thinks that corn acres will be 2 million or so lower than the intended 86 million acres and that bean acres will be below intended levels as well.

A Drought? Really?
In what could be one of the greatest ironies ever, some climatologists and meteorologists still believe we could see a drier than normal summer. Elwyn Taylor of Iowa State University declared that to an audience at World Pork Expo last week and Drew Lerner of World Weather, Inc. repeated it in a CME Group outlook webinar yesterday. Their concerns are based on longer-term cycles and the fact that the Southeast was very dry last year. Taylor points out that 16 of the past 17 midwestern droughts have been preceded by droughts in the Southeast the year before, and only twice has one in the Midwest not followed a southeastern drought.

We saw this pattern in 1983. Though not nearly as wet as this year, the spring of ’83 saw ample rainfall before heat and drought scorched crops throughout the Midwest. A repeat of that pattern would add insult to injury.

Click to view graphs.

Steve R. Meyer, Ph.D.
Paragon Economics, Inc.
e-mail: [email protected]

Three Factors Will Shape U.S., Canada Pork Industries

The Canadian and U.S. pork industries will be primarily shaped by three factors, over the next 12-18 months. These factors, all of which are at unprecedented levels, include:

  • Remarkably strong live hog demand – The combination of hog quantity and price has never before been as high as it was in April and May.
  • Record-large supplies – Last week was just the second week of 2008 (the first being New Year’s week) in which U.S. FI hog slaughter was not record large for the respective week.
  • Record-high production costs – My production forecast for market hogs sold in June (based on production parameters from Iowa State University) is $78.66/cwt. carcass, the highest ever. But higher costs are coming.
Will these three factors change in the coming months? Increase? Remain near today’s levels? Decline? Those are huge questions upon which much of the future of the industry will ride. More important for your operation is “Do you have a plan to handle these three factors NO MATTER WHICH DIRECTION THEY MOVE?” Such a plan will not be easy but you should be thinking about each of them.

What can you do about hog demand? Producing hogs without quality and utilization defects (i.e., they must have high lean content, high quality lean and fat, have no drug residues, be within your packer’s preferred weight range, etc.) is the demand-enhancing item most clearly within your control. But beyond that, there isn’t much that you can explicitly do.

Today’s strong demand is still being reflected in high CME Group Lean Hogs futures relative to current cash prices and cash price forecasts that I think are justified by future supplies. So, even if you cannot do much to impact hog demand, you can take action to capture recent strength.

We will get another read on future supplies when USDA publishes its June Hogs and Pigs Report, and Statistics Canada publishes its July Hog Statistics report. Every indication from the respective March and April reports was for record-large slaughter in most of the remaining weeks of 2008 with fourth-quarter U.S. FI slaughter in excess of 30 million head.

The recent run-up of cutout values and hog prices accompanied smaller hog slaughter totals – relative to recent levels. But those totals were still roughly equal to the levels suggested by the March Hogs and Pigs Report. The weeks prior to that were 3.5% LARGER than suggested by the report. The rise in prices was impacted by smaller hog slaughter but not SMALL hog slaughter by any stretch of the imagination.

The key here will be to have hog marketings current when the fourth quarter arrives. If you are considering lower market weights, you must get them lower this summer. When September arrives, slaughter runs will be large enough that you will have no opportunity to move pigs quicker and bring weights down. You have about 3 months.

The production-cost situation just seems to get worse every day. Using June 2 futures prices, costs are forecasted to exceed $85/cwt. beginning with March 2009 sales. Thursday’s near-limit move for corn and limit move for soybeans will drive the cost forecasts even higher.

And the weather is not cooperating at all. As can be seen from Figures 1 and 2, corn planting progress and corn emergence are at or below the slowest paces on record. These do not mean a disaster is coming but this crop is going to need some help in terms of heat-degree days. It appears that corn will not be planted on 3-4 million the 86 million acres intended to be planted to corn. Late planting and emergence will, quite likely, result in below-trend yields. The big question now is “How much below trend?”

I hope next week’s Crop Production report will give us a better idea of what is to come but I don’t believe it will. After seeing May’s projected usage numbers, I fear that USDA is simply trying to make the numbers work instead of telling us what will be the logical result of high ethanol production on top of a disappointing crop. Prices will almost certainly have to go higher than the levels in the May report to drive ethanol, livestock, industrial use and/or exports to reduce corn usage.

Click to view graphs.

Steve R. Meyer, Ph.D.
Paragon Economics, Inc.
e-mail: [email protected]

April Pork Exports Smash Previous Record

U.S. pork exports continued to excel in April, beating the previous one-month record by nearly 12% to reach 387.2 million pounds of pork and pork variety meats valued at $391.5 million. The previous record, 346 million pounds exported, was set in February.

The pork success story becomes more compelling by comparing exports for the first four months of 2008 vs. 2007. Total pork exports for 2008 rose by an impressive 52% over the year prior to 1.38 billion pounds worth $1.4 billion.

“U.S. pork has set export records for 16 consecutive years, and there’s no sign that the world’s appetite for U.S. pork is slackening one bit,” says Erin Daley, manager of research and analysis for the U.S. Meat Export Federation (USMEF).

In the first four months of 2008, exports comprised 22% of total U.S. pork and pork variety meat production, compared to 16.5% last year.

Year-to-date highlights by country/region include:
-- Japan was still the top buyer with total pork exports up 17% to 319.5 million pounds valued at $460 million;

-- The China/Hong Kong region follows closely behind with exports up 311% to 319.2 million pounds valued at $243.5 million. April exports set a new record for the region at 93.3 million pounds;

-- Exports to Mexico were up 10% to 228.5 million pounds, but still lag record 2006 volumes by 16%;

-- Exports to Russia set a new record in April at 40.7 million pounds for a January-April total of 128.6 million pounds, up 142% from the first four months of 2007;

-- Exports to Canada were up 24% to 117.6 million pounds;

-- Exports to South Korea were up 12% to 107 million pounds;

-- Exports to Southeast Asia were up 316% to 34 million pounds, and

-- Exports to the European Union were up 117% to 30.1 million pounds.

Imports of live Canadian hogs rose 14%, with feeder pig imports up 19% and slaughter hog imports up 4.5%, through May.

The forecast for U.S. pork exports for 2008 declined slightly, but shipments are still projected to finish 36% above last year.

Pork production estimates for 2008 and 2009 also were lowered slightly, reflecting lower live imports from Canada and lower U.S. pork production in response to higher grain prices.

Per capital pork consumption is expected to decline by about a pound from an estimated 50.7 lb. in 2008 to 49.6 lb. in 2009, according to USMEF.

Pork Board Mounts Efforts To Help Producers Survive

The National Pork Board (NPB) has instituted a three-pronged approach to help financially strapped pork producers, building upon a foundation of accountability, trust and social responsibility.

“We know that many producers are struggling right now with a profitability challenge,” says Steve Murphy, chief executive officer (CEO) for the National Pork Board. “The pork checkoff is helping producers work together to build a stronger industry. Producers are using the checkoff in many ways to build demand, move more product and raise a better product.”

Pork exports are a key ingredient, capturing the 16th-consecutive record year of growth in 2007. U.S. pork exports in the first quarter of 2008 were valued at more than $1 billion.

“One in every four pounds of pork traded today originates from the United States,” says Murphy.

Domestically, the pork checkoff program launched The Other White Meat Tour to celebrate pork’s positive attributes with target consumers through cooking demonstrations, product sampling and one-on-one interactions. The tour will stop at 23 major consumer events across the United States that reach a large percentage of the pork checkoff’s target audience: females 25-49 years old who have children at home and want to improve their cooking.

“A total of 250 million pounds of pork have been sold as a result of checkoff retail programs during the first and second quarter,” reports Murphy. “Of that, 52 million pounds are incremental increases compared to the same period last year.”

He adds: “From grilled breakfast sandwiches at 1,000 Panera Bread Bakery locations to a new Butcher’s Block line of fresh and frozen pork at 77 Sysco distribution centers, putting more pork on the menus continues to be a focus.”

Efforts are also being made to focus on input resources with creation of Practical Ideas to Address High Feed and Production Costs, comprised of a list of management tips and resources to help improve efficiencies and reduce costs.

“The CME (Chicago Mercantile Exchange) Group, pork checkoff and state pork associations have come together to develop risk-management webinars,” says Murphy. “These online, interactive presentations give producers direct access to industry professionals.”

The 2009 NPB budget will be based on producers working together to build a stronger industry.

“An early step in the process is to identify the critical issues for 2009,” notes Lynn Harrison, NPB president. “With producer direction and input from Pork Forum, board meetings and committee meetings, the board approved the 2009 critical issues.”

Five critical issues include:
-- The competitive advantage for U.S. pork;
-- The safeguard and expansion of international markets;
-- Domestic pork expenditures;
-- The trust and image of the industry and its products; and
-- Human capital – the development of producer leadership and technical advisors and the growth of a quality workforce.

“We will continue to work with producers and staff through the next few months in the budget process with the approval expected in November,” says Harrison. “We are also in the process of a search for a new CEO.

“Earlier this year we contracted with a professional search firm and worked with producers to determine what is needed in a new CEO,” he comments. “We are moving through the process and expect to make an announcement later this year. This is an important decision and we want to make sure that we are doing the right thing for our producers as we hire this position.”