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Articles from 2003 In October


Court Rules Pork Checkoff Unconstitutional

The U.S. Court of Appeals for the Sixth Circuit ruled Oct. 22 that the Pork Checkoff is unconstitutional, upholding a November 2002 decision by a federal-court judge in Michigan.

The Pork Checkoff was created by Congress so all pork producers would contribute to a fund for promotion, research and consumer information about pork. The federal lawsuit and subsequent appeal focused on whether the Checkoff violates the First Amendment rights of some producers who disagree with specific Checkoff promotional messages.

"This is disappointing news for America's pork producers," said Craig Christensen, a pork producer from Ogden, Iowa, and president of the National Pork Board, which collects Checkoff funds and manages Checkoff-funded programs. "At the same time, we recognize this is just one more step in a lengthy legal process in which the Pork Checkoff is represented by the U.S. government."

Until directed otherwise, Christensen said, the Pork Checkoff will continue to provide programs for all producers to increase the demand for pork and to provide access to the knowledge and opportunities that allow all producers to be competitive.

The U.S. Department of Justice, in consultation with the U.S. Department of Agriculture, will determine the next steps in the legal process. The Department of Justice has 45 days to decide whether to ask for a rehearing by the Sixth Circuit in Cincinnati. The Department of Justice also can seek review of the case by the Supreme Court. Christensen said that the USDA and Department of Justice have supported the Pork Checkoff program throughout the legal process.

Since 1987, the Checkoff has been at work for producers to promote pork, to increase demand for pork, to expand markets for pork and to provide on-farm information. "The success of the Pork Checkoff has been well documented," Christensen said. "We all invest in the Checkoff and the Checkoff delivers, especially for pork producers."

Through Checkoff-funded promotions and advertising, Pork. The Other White Meat® has become one of America's most recognized advertising taglines. Exports of U.S. Pork have set new records for 11 consecutive years. Checkoff-funded research continues to help U.S. farmers produce safe, high-quality pork and to be environmental stewards, Christensen said.

National Pork Board has responsibility for Checkoff-funded research, promotion and consumer information projects and for communicating with pork producers and the public. Through a legislative national Pork Checkoff, pork producers invest $0.40 for each $100 value of hogs sold. The Pork Checkoff funds national and state programs in advertising, consumer information, retail and foodservice marketing, export market promotion, production improvement, technology, swine health and pork safety. For information on Checkoff-funded programs, pork producers can call the Producer Service Center at 800-456-PORK or check the Internet at www.porkboard.org.

Genetic Disease Resistance Symposium

Genetics of Pig Health Symposium, sponsored by the National Pork Board, is Nov. 18-19 at the Des Moines (IA) Marriott.

The program covers challenges to pig health improvement, genetic selection for improved pig health and experiences in the poultry, beef and dairy cattle industries.

Other presentations focus on nutritional influences on animal health, genomic tools and new approaches for improving disease resistance.

For registration information, call toll-free (800) 456-7675. Reserve a room at the hotel by calling (515) 245-5500.

TGE, Rotavirus Still Impact Bottom Line

Transmissible gastroenteritis (TGE) and rotavirus are the most important viral causes of diarrhea in U.S. swine.

TGE is a highly contagious disease. It can affect swine of all ages and cause high death loss in pigs less than 2 weeks of age.

TGE has been the focus of intensive disease control efforts for many years. Diagnostic laboratory records indicate that these efforts have resulted in a large decrease in TGE diagnoses in suckling and nursery pigs with diarrhea, from 26% in 1988 to 6-7% in 2002.

Rotavirus is a highly resistant virus that is present in most herds. Rotavirus most commonly causes a low-level infection without clinical signs (subclinical infection) or mild diarrhea.

How These Viral Agents Work

TGE and rotavirus infect cells covering finger-like projections (villi) lining the intestine (Figure 1). Viral infection leads to loss of these cells and an atrophic enteritis (the finger-like villus structures become shortened, blunted and fused), resulting in decreased digestion and absorption with subsequent diarrhea, dehydration and weight loss (Figures 2 and 3).

Both viruses multiply in the intestine, are shed in feces, and are transmitted to other pigs primarily when they ingest infective fecal material.

No Magic Bullet

One of the difficulties in dealing with intestinal viruses of swine is that there are no medications that will eliminate them. Once a pig is infected, supportive care can decrease mortality, but the pig's immune system must eliminate the virus.

Because swine intestinal viruses cause an atrophic enteritis, recovery is often delayed while intestinal villi regenerate.

Clinical Signs

Clinical disease due to TGE and rotavirus is most common in suckling and nursery pigs. The primary clinical sign with both viruses is diarrhea, leading to dehydration and weight loss. Other common clinical signs with TGE include fever, lethargy, piling and vomiting.

The incubation period for both agents is short (1-3 days), so there is the potential for rapid spread, particularly with TGE. It isn't uncommon for pigs to become sick very soon after delivery. This makes it seem like the farm of origin was the source of infection, when in fact, the source may often be the delivery vehicle.

Rotavirus is present in most herds, but diarrhea is most common in pigs 4 to 41 days of age. Infections are most often undetectable or result in mild diarrhea.

TGE is more common in the winter from November through March. Potential reasons for this seasonality include:

  • The virus survives well in the cold but is inactivated at warm temperatures, and

  • Chilling and temperature fluctuations predispose the pig to development of TGE. Disease due to TGE occurs in two relatively distinct forms: epizootic (outbreak) or enzootic (ongoing problem).



Epizootic TGE occurs when the virus is introduced into a naïve herd. The typical clinical signs in piglets are brief periods of vomiting, accompanied by severe, watery diarrhea with rapid weight loss, dehydration and a high incidence of sickness and death loss in pigs under 2 weeks of age. Most pigs under 7 days of age will die, while most pigs over 3 weeks of age will survive, but are likely to remain unthrifty for a period of time. Getting these pigs back on feed as soon as possible and minimizing body weight loss are the primary treatment objectives in order to minimize economic losses.

Clinical signs of TGE in grow/finish and adult swine are usually limited to diarrhea and loss of appetite for a few days, with vomiting seen in an occasional animal.

Enzootic TGE is a milder form of this enteric disease. Pigs generally develop diarrhea 1-2 weeks after weaning, as passive antibody levels decline; mortality is typically low.

Concurrent Infections

TGE and rotavirus cause changes in the intestine that can predispose the animal to developing concurrent Escherichia colibacillosis (E. coli) or Clostridium perfringens Type A enteritis, which can increase the severity of the diarrhea. If these pigs are treated with antibiotics effective against the secondary bacterial infection, they may show clinical improvement and decreased mortality. However, treatment will not completely eliminate the diarrhea.

Determining Disease Severity

Differences in clinical signs are not generally due to different strains of virus. The severity of disease is determined by the level of immunity from ingested colostrum, exposure dose, presence or absence of concurrent infections (E. coli) and the age at exposure.

While explosive outbreaks of TGE occur when the virus infects non-immune herds, the enzootic form of TGE occurs when sows pass colostral immunity against TGE onto their offspring. This immunity protects pigs during the critical first few weeks of life. But as immunity begins to wane, and partially immune pigs are exposed to the virus, they develop milder forms of the disease.

Experimentally, when newborn pigs are exposed to rotavirus, they develop severe diarrhea with significant mortality. Yet most field infections are subclinical or mild.

Because rotavirus is extremely common, most sows are immune, and as with enzootic TGE, subclinical infection or mild diarrhea occurs.

Clinical rotavirus problems occur most commonly in “start-up” herds or herds with a disproportionately large number of gilts. These herds may lack adequate protective immunity, and rotavirus infection in suckling pigs will cause higher mortality and greater reduction in weaning weights than is typically seen in more mature herds.

Table 1. Viral Infectious Causes of Diarrhea in Swine*
Disease 1-7 days 7-21 days Nursery
TGE 6% 8% 7%
Rotavirus 6% 14% 12%
E. coli 9% 11% 49%
Salmonella 0.5% 5% 17%
Coccidia 1% 20% 15%
Clostridium difficile 29% 2%
Clostridium perfringens Type A 13% 2%
Clostridium perfringens Type C 6% 4%
*Iowa State University Veterinary Diagnostic Laboratory Data, 2000-2002.


For both TGE and rotavirus, there is an age-related resistance — the older the pig, the less severe the illness. Also, modern slotted flooring has greatly reduced exposure to fecal material and to these viral organisms. Low-level exposure of older, partially immune pigs leads to a milder or subclinical form of disease with either virus.

Diagnostics

As described, an explosive outbreak of diarrhea with vomiting, affecting all age groups with large losses in young pigs, would be indicative of TGE. A low morbidity, low mortality scour in suckling pigs that is not responsive to antibiotics would be more suggestive of rotavirus. However, there is considerable overlap in clinical signs between agents that cause pig diarrhea.

If a diagnosis cannot be made on the basis of clinical signs and response to treatment, producers or veterinarians should select live, acutely affected, untreated pigs as the specimen of choice for complete diarrhea diagnostics.

Do not pull a pig off the dead pile for this diagnostic work, because the intestine degrades rapidly; in less than 30 minutes (especially when hot), the gut is useless for a number of diagnostic tests.

Do not select stalled-out pigs that have had diarrhea for several days or pigs that have been treated. Stalled-out pigs may still have diarrhea due to residual intestinal damage (atrophic enteritis). But these pigs are now recovering from infection and the virus is no longer detectable. If pigs have been treated with antibiotics, the viruses may still be detectable, but therapy may prevent the identification of concurrent bacterial infections (antibiotics do not affect viruses.)

TGE Look-Alike

Porcine Epidemic Diarrhea (PED) is an important cause of viral diarrhea in Europe and Asia, but has not been detected in North America. PED cannot be reliably differentiated from TGE on the basis of clinical signs or gross or microscopic lesions. If clinical signs and lesions are suggestive of TGE, but extensive testing fails to identify TGE, samples (feces or fresh intestine) can be forwarded to the National Veterinary Services Laboratory in Ames, IA, for PED testing.

Treatment and Control

The early treatment of viral enteritis is important in getting pigs back on track as quickly as possible. Due to the nature of viral infections, treatment must focus on supportive care and suppression of secondary bacterial infections. Because of profuse diarrhea and vomiting, fluids and electrolytes are quickly lost from the body. Supplying the pigs with oral, water-soluble electrolytes helps reverse this process. Electrolytes can be provided to pigs using a medicator.

Because pigs are often lethargic and chilled due to fever, anti-pyretic/anti-inflammatory compounds, such as aspirin, are also helpful. If pigs are chilled, additional zonal heating or increasing room temperature can improve pig comfort.

The goal of treatment is simply to convince pigs to feel normal with the hope they will soon return to eating and drinking normally.

In sow herds, TGE will typically cause very high death loss in nursing pigs. To bring the disease under control, it is imperative to expose the whole herd as quickly as possible to reduce the length of time that weaning piglet quality and numbers are affected. It is prudent to stop the introduction of new breeding stock to allow the infection to “burn itself out.”

It is possible to eradicate TGE from a herd through planned exposure to the virus and by halting the introduction of na've animals. This can be done in a number of ways. It's best to consult with your veterinarian regarding protocols for specific farms.

Prevention

Because rotavirus is very hardy and stable, it exists on the vast majority of swine farms. Through proper management of colostral immunity, rotavirus-positive farms are generally not an economic burden.

However, this is not the case for TGE. Epizootic TGE can be and often is devastating to a sow herd's productivity and economic health. The best way to control it is to prevent entry into a farm by paying special attention to several cornerstones of good biosecurity:

  • Never underestimate the potential for an unclean transport vehicle to cause problems. Trucks and trailers need to be cleaned of all organic matter, disinfected and thoroughly dried before being allowed on a farm site. Frozen wash water on trailer floors is unacceptable and may in fact be the perfect way to preserve TGE virus.

  • Use of a shower-in, shower-out or Danish entry protocol is wise. The Danish entry protocol consists of washing hands and changing outerwear before entry into facilities. Clothing and footwear worn off the farm should not be worn on the farm.

  • Delivery and feed trucks should be kept as far away from buildings as possible. It is best if these vehicles don't come to your farm directly from other farms, but this is very difficult to control.

  • Equipment-sharing among farms is generally not recommended.

  • Visitors to your farm should understand and abide by your biosecurity protocols. Reducing the number of visitors to a farm is often prudent, especially in cold weather months. Generally, reducing the traffic across your farm is wise as well.



Once a downstream site has been diagnosed with viral enteritis (especially TGE), it is important not to track it back upstream to the nursery or sow herd. One-way flow of pigs and people through the system is advisable.

As with any disease problem, it is important to get a specific diagnosis as quickly as possible so that the proper control measures can be implemented.

Pork production has turned into a battle of numbers. Controlling economic loss due to infectious disease is critical to financial performance. Viral enteritis may not be as threatening as some of the newer, emerging diseases. Nonetheless, it still has the capacity to sting you where it counts most — in the pocketbook.

New and Old Players Plague Producers

Bacterial diarrhea (enteritis) in swine continues to be a daily challenge for pork producers and veterinarians in treating affected pigs. Some bacteria causing diarrhea have been consistent problems over the years, while other types have declined in case numbers only to be replaced by newly identified bacteria.

Reviewed in this article are some of the common bacteria currently and historically associated with diarrhea in pigs. The frequency of the different types of bacteria associated with diarrhea in pigs may vary by site and by production system.

General Diagnostic Tips

When trying to identify the bacteria causing diarrhea, it is important to select pigs in the early stages of the disease that have not been treated with antibiotics. Testing pigs in the later stages of diarrhea, or pigs that have been treated with antibiotics, may yield negative or inappropriate results. Most diagnostic efforts involve testing for multiple agents.

The types of bacteria that produce diarrhea are commonly age associated. For pigs still in farrowing crates, Clostridium perfringens Type A and Escherichia colibacillosis (E. coli) represent the more common agents. Clostridium difficile and Clostridium perfringens Type C are identified less often.

Clostridium perfringens

Clostridium perfringens Type A represents one of many types of Clostridium perfringens causing diarrhea in young animals (Figure 1). Clostridium perfringens Types A through E are differentiated by the type(s) of toxins (specifically one or more of four exotoxins) each produces. Pigs most likely to get this diarrhea are infected with Clostridium perfringens by oral exposure to feces.

Clostridium perfringens isolates are currently typed by polymerase chain reaction (PCR) technique to identify the gene responsible for toxin production. Many of the Clostridium perfringens Type A isolates associated with diarrhea are also positive for the beta-2 toxin gene.

Clostridium perfringens Type A is commonly found in most farms. The spore form of the organism easily survives in the environment.

Diarrhea most commonly occurs within the first three days of life and may last for up to five days. Clostridium perfringens Type A infection results in a watery-to-pasty, white-to-yellow diarrhea. Pigs will lose some body condition and growth slows. The affected intestine may look normal or slightly thickened.

The number of pigs affected may be high, but death from Clostridium perfringens Type A alone is considered to be low.

Clostridium perfringens can be isolated from the small intestine of affected pigs by anaerobic culture. Histopathologic lesions (structural tissue changes viewable with a microscope) also help define it as a causative agent.

E. coli in Nursing Pigs

E. coli diarrhea in nursing pigs usually occurs within the first seven days of life and, even more commonly, between three hours and four days of age. Pigs from gilt litters are more commonly affected due to less colostral antibody protection.

Other factors that may influence the development and severity of E. coli diarrhea in young pigs include dirty crates at farrowing and low air temperature.

Most E. coli attach to the surface of the small intestine by fimbriae (a filamentous bacterial cell wall appendage that binds to the surface of the pig's small intestinal cells). The types of receptors vary and have been given different designations such as K99, F41 and 987P. The E. coli attach to small intestine cells and produce toxins, causing fluid loss into the intestine and the resultant diarrhea.

Clinical signs usually include severe watery diarrhea, dehydration, sunken eyes, lethargy and death, if left untreated. The affected intestine may be fluid-distended and thin-walled or empty.

The E. coli that is infecting the pigs can be cultured from small intestine as well as attachment to intestinal cells identified by histopathology. The E. coli can be further typed by PCR characterization of the fimbrial (pilus) and toxin genes.

Clostridium difficile

Clostridium difficile is one of the more recently recognized bacteria associated with baby pig diarrhea. Like Clostridium perfringens, Clostridium difficile is also commonly found in the environment.

Clostridium difficile has been associated with diarrhea in pigs up to 10 days old. Affected pigs show a mildly distended abdomen, with or without diarrhea; lethargy; and temporary loss of appetite. The affected colon is commonly edematous (thickened by clear fluid). The number of sick pigs may be high, but mortality is generally low.

As with Clostridium difficile infection in other species, development of infection may be linked to prior oral antibiotic treatment that changes the normal intestinal bacterial population.

Diagnosis of Clostridium difficile infection is usually evident by typical lesions in the colon and identification of toxin in colon contents. Clostridium difficile culture requires special conditions.

Postweaning E. coli Diarrhea

Postweaning E. coli diarrhea is usually associated with two groups of bacteria designated by their fimbrial type, K88 and F18. As with E. coli infection in preweaned pigs, the E. coli bacteria binds to intestinal cells and secretes toxins, resulting in fluid loss(Figure 2).

In addition, some postweaning E. coli may secrete a toxin known as shiga-like toxin, which is responsible for the development of central nervous system signs such as staggering, uncoordination, poor balance, paddling and convulsions.

Both K88 and F18 E. coli may exist and cause clinical disease in the same group of pigs. In some cases, K88 E. coli infections precede F18 infections.

Postweaning E. coli infections can be distinguished by a variety of clinical signs, including watery red/bloody diarrhea; loss of appetite; central nervous system signs; and sudden, unexpected death. Pig eyelids may appear remarkably swollen and intestinal contents are liquid. The gastrointestinal tract in some pigs may be completely empty at death.

The type of E. coli involved in the diarrhea can be further characterized by PCR typing. This process can identify the genes in the bacteria that code for the fimbrial type as well as the genes responsible for toxin production.

It is important to properly identify the E. coli responsible for disease in order to develop appropriate treatment and control plans.

Salmonella

There are many types of salmonella that can infect pigs; however, the two types associated with clinical diarrhea problems in pigs are Salmonella typhimurium and, less commonly, Salmonella cholerasuis.

Other types of salmonella may be implicated in short-lived episodes of diarrhea, but generally don't have the serious implications of S. typhimurium and cholerasuis infections. Some salmonella infections in pigs are asymptomatic.

Salmonella diarrhea usually affects pigs from postweaning to 4 or 5 months of age; however, it is occasionally seen in adult swine.

Salmonella typhimurium infection results from contact with infected pigs or a contaminated environment. Once contaminated, some facilities may remain the source of infection for new groups of pigs.

Pigs infected with Salmonella typhimurium may be subclinically (inapparent) infected or develop diarrhea. The bacteria infect both the small and large intestine, inducing fluid loss that results in diarrhea, and damaging the intestinal surface.

At first, affected pigs will have a watery diarrhea that may contain flecks of blood and mucous. Pigs are also febrile (feverish), dehydrated and show signs of weight loss. The diarrhea quickly spreads to other pigs in the pen and is easily tracked to other locations. Pigs may have recurring episodes of diarrhea over several weeks. The colon and intestine in affected pigs may be thick-walled with an ulcerated surface lined by small to large pieces of debris.

Salmonella cholerasuis infection may also result in diarrhea and intestinal damage if the pigs survive the severe, initial septicemic (invasion of the bloodstream by infective organisms) stage of the disease.

Salmonella diarrhea can be diagnosed by culture and examination of tissues by histopathology.

Porcine Proliferative Enteritis

Porcine proliferative enteritis (PPE) caused by Lawsonia intracellularis is an intestinal disease of swine occurring in pigs from 6 to 20 weeks of age. But it also occurs in adult hogs.

Infection can take two diverse routes. It can result in severe intestinal disease and death, or occur as an inapparent infection with disease presented only as decreased performance (Figure 3).

The bacteria are shed in the feces of all clinically infected pigs, but also in pigs with inapparent infections. Transmission between pigs occurs through direct contact with feces from infected pigs. Ingestion of the bacteria results in infection of small and large intestinal cells, and clinical diarrhea usually starts 2-3 weeks later. Diarrhea may occur in less than half of the infected animals, however.

Clinical disease may take a chronic form or an acute, hemorrhagic form. In the chronic disease form, pigs may have a soft-gray/brown stool that alternates with normally-formed stools on other days. Appetite usually decreases and pigs become thin. There may be size variation within the group. Pigs will normally recover in four to 10 weeks.

Both the large and small intestine may be affected, but changes are usually more severe in the small intestine. The intestinal wall appears slightly to markedly thicker and the surface may be lined by a thick layer of yellow/white debris.

The acute, hemorrhagic form of PPE or ileitis is more common in young adults and is characterized clinically by loose-to-formed black (bloody) feces and a pale body color (due to blood loss) (Figure 4). Some pigs die suddenly without showing any signs of diarrhea or blood loss in the stool. The intestine in this form of the disease is usually thick-walled (Figure 5) and the cavity contains blood or blood clots.

Diagnosis of PPE by histopathology is usually straightforward in pigs with obvious intestinal changes. The bacteria can be demonstrated with special stains under the microscope or by PCR. However, the bacteria are very difficult to grow; culture is not even attempted in routine testing.

Subclinical forms of the disease can be even more challenging to diagnose. The bacteria can be identified in the feces of clinically affected pigs by PCR but not in all subclinical infections. Serologic testing is available, but the number of pigs seroconverting in a group may move slowly, with only 5% to 50% positive.

Swine Dysentery (Brachyspira hyodysenteriae)

Swine dysentery, primarily a disease of growing and finishing pigs, causes severe catarrhal (abundant mucous) and hemorrhagic colitis. The number of cases of swine dysentery has decreased dramatically, with success for control and elimination credited to antibiotics and modern production practices.

Transmission of the bacteria is through fecal shedding by infected pigs to susceptible pigs. Contaminated pit waste, mice, birds and dogs are other potential sources of infection and disease spread.

Disease usually spreads slowly within a herd. Affected animals develop diarrhea, dehydration and weight loss, and death losses may be as high as 50%. The bacteria grow in the colon (not the small intestine), producing toxins that result in damage to the colon.

Diarrhea is associated with malabsorption rather than fluid loss. The diarrhea associated with swine dysentery is initially a watery, yellow diarrhea that progresses to large amounts of blood-flecked, mucous-filled stool. At necropsy, the colon wall is markedly thickened and the surface is covered by a thick layer of mucous, blood and cell debris. The lumen or organ cavity may be filled with blood and cell debris forming luminal casts.

Diagnosis is by histopathology, culture and isolate verification using PCR analysis.

Porcine Intestinal Spirochetosis (Brachyspira pilisicoli)

Brachyspira pilisicoli is related to, but distinct from, the causative agent of swine dysentery. The bacteria are identified with a syndrome of mild diarrhea caused by a mild colitis. Production losses are associated with treatment costs and a loss of body condition. Mortality is very low.

Infection is thought to occur by the fecal-to-oral route. The incubation period may be up to 20 days and infected pigs develop a self-limiting, soft-to-watery diarrhea that lasts from two to 14 days. Colon and cecum (opening to the large intestine) in affected pigs appear thin-walled and filled with soft, green feces.

Diagnosis is by culture, histopathology or immunohistochemistry and PCR-based typing.

Conclusion

The bacteria causing diarrhea in pigs will continue to be recurring problems for pigs, producers and veterinarians. In some cases, antibiotics are no longer an option due to resistant bacteria. Sanitation plays an important part in controlling intestinal diseases of swine.

Strategies To Control Enteric Pathogens

Over the last decade, pig production has changed dramatically. But enteric pathogens continue to have a major impact on modern swine production.

Some of the more prevalent pathogens of the past, such as swine dysentery, have been replaced with diseases such as F18 Escherichia coli (E. coli), salmonella and porcine proliferative enteritis (ileitis).

Yet many of the old diseases are still very common, including Transmissible gastroenteritis (TGE), rotavirus and coccidiosis.

Whether designing new pig production systems or learning how to operate existing units, many of the management and control efforts for enteric disease are remarkably similar to strategies of the past.

Pig Flow

For pig flow, the main goals are to put pigs of similar health status together, limit age spread on site and use all-out pig flow before repopulating a site.

Similar health is best achieved by limiting the number of sow farm sources per site. A balance between how fast a site is filled and the number of sources is also important. Porcine reproductive and respiratory syndrome (PRRS) has taught us to follow good pig flow rules. But that's also very true for many enteric diseases.

If it's not possible to keep pigs of the same health status together, try to equalize pig immune status before commingling with vaccines such as salmonella, E. coli and ileitis.

When flowing pigs out to the nursery/finish site, make sure sites are flowed with pigs of the same health status as the previous turn.

Sanitation

With enteric disease, it is critical that a stringent sanitation protocol is followed so when all the pigs are removed from the site, the disease agents are also removed.

Enteric pathogens are fairly hardy organisms. Under the right circumstances, many can live for months outside the pig (Table 1). Therefore, as a general rule, pork producers need to work harder on sanitation to rid the environment of enteric pathogens than they would for respiratory pathogens.

Heat and dryness are the two factors that kill enteric pathogens. Clearly, this is why many enteric pathogens seem to spread more easily in the cool, damp times of the year.

If you are having problems with enteric pathogens on your farm, reevaluate sanitation between groups of pigs. Sanitation fails when we fail to remove all of the manure and organic matter from a site prior to new pigs arriving.

Table 1. Pathogen Potential Survival Times
E. coli three months
Salmonella >nine months (if cool/damp)
TGE > one year (if cold)
Swine Dysentery 60 days (mice up to one year)
Roundworm Eggs several years


The first step to ensure that sanitation is done correctly is presoaking. Many producers have automatic soakers in the barns set on timers, which allow good soaking action and loosening of organic material without filling the pit with more water.

In addition, it is helpful to use detergents or soaps prior to pressure washing to help loosen organic material. This can be done with foam applicators or by wetting the barn down with soap prior to washing.

Next comes the most important job of thoroughly washing the barn and removing all organic material with the high-pressure sprayer. Focus on areas where you know it is difficult to remove all the manure. After this is done and the barn is allowed to dry, inspect the area using a flashlight and chalk (Table 2). Look for problem areas where you can typically see manure, such as under feeder lips and water cups, on the bottom of gate rods and in the joints between slats and stem walls. A stem wall is a concrete wall poured 6-12 in. from the floor up. Then a wood wall is constructed on top. This keeps moisture away from the wood wall. In wean-to-finish facilities, creep mats are especially important. In general, the mats are hard to wash and are the most frequent areas of contamination for new pigs entering the facility. In cases of F18 E. coli outbreaks in nurseries or wean-to-finish barns, the mats are often set out for an entire turn, and disposable mats (a 4 × 8 sheet of ¼-in. plywood) are used. After the turn, burn the plywood sheets.

Then rewash the problem areas found on the inspection, allow the barn to dry again and apply disinfectant.

Also, make sure that the loading chute and the non-pig areas of the barn (office, entryway) are clean and free from any organic matter.

Disinfectants

Disinfectants are the final step to provide insurance that all the pathogens are dead prior to new pigs arriving.

Since drying is a very effective strategy for killing pathogens, ensure the barn dries both after the wash and the disinfectant application before pigs are allowed entry.

Disinfectants can be applied in many ways. A hose end applicator set at the correct dilution ratio is an effective strategy for applying disinfectant at the correct concentration. Another option is applying the disinfectant with a suction apparatus at the end of the high-pressure sprayer wand. This method needs to be calibrated so the right concentration is applied. Read the label of each product so the correct dilution is used. If your sprayer puts out 4 gal./minute and it takes 30 minutes to wet all surfaces, a total of 120 gal. needs to be used. If the correct dilution ratio is ½ oz. of product/gal. of water, a total of 60 oz., or nearly ½ gal. of disinfectant needs to be used.

Table 2. Barn Sanitation Checklist
• Inside feeder lip
• Bottom side, bottom gate rod
• Bottom side and inside water cup
• Creep mats
• Slat joints/grout lines
• Sides of slats
• Stem walls — sides and top
• Edge of barn next to stem wall
• Loading chute
• Office and barn entry area
• Supplies — boots, coveralls, gloves, panels, prods, syringes
Look closely at these problem spots. Use a flashlight and mark areas to be rewashed with chalk. Must not see any visible manure.


Also, disinfectants can be applied through foggers that fill the entire barn with a fog of the disinfectant. I like to rotate disinfectants on a quarterly basis and use a different class of disinfectant for each quarter (Table 3, page 32).

Environment

Enteric disease in pigs is actually a complex interaction between the number of “bugs” present in the environment, immunity levels of the pigs and concurrent stresses occurring within the pigs' environment.

We must be aware of the environmental stresses and deal with them on a daily basis. We can manage environmental stress by controlling the pigs' environment to the best of our ability.

One of the most common errors I see in nursery and finish facilities is a lack of understanding of the ventilation controller. It is critical to know how the controller works and if the settings are correct to provide pig comfort. Understand each stage of ventilation, the number of fans operating during that stage, the temperature each stage comes on and goes off, and how fast each stage ramps to 100%.

Table 4 on page 33 provides temperature recommendations by age of pig.

Follow these “Golden Rules” to keep pigs healthy and happy:

  • Keep pigs dry;
  • Keep pigs warm;
  • Keep pigs draft-free; and
  • Make sure pigs have fresh feed and fresh water.


I know it sounds too simple — but it's amazing how often these basic rules are broken and how much enteric disease is present because of these errors.

Keep Pigs Dry

In general, enteric pathogens cause diarrhea. When we have more diarrhea on top of the slats, we have more humidity in the barn. As stated earlier, drying kills many of these enteric pathogens. Therefore, it is critical that we keep humidity levels in the barn between 50-65%. Measure the relative humidity with a humidistat reader to get a feel for the correct humidity level.

Humidity levels are controlled in finishing barns by ventilation rates. If humidity levels are too high, the minimum ventilation rate is too low.

Table 3. Disinfectant Comparison
Chlorhexidine Chlorine Quaternary Ammonium Phenolic Cleaner Iodophors Formaldehyde Potassium Peroxymono-sulfate
Primary Products Nolvasan Bleach Rocal Annihilator Vetphene; Environ One Stroke Premise Cleaner Gentle Iodine Betadine DC&R Virkon S
Effective Against Viruses Yes Yes Yes Fair Yes Yes Yes
Speed of Kill Fast Moderate Moderate Moderate Moderate Slow Fast
Effective Against Fungus Yes Yes Yes Yes Yes
Sporicidal at Room Temperature No No No No Yes Yes
Effects of Hard Matter None None (unless alkaline) Reduced Speed of Kill None None (unless alkaline)
Effective with Cold Water Yes Yes Yes Warm Best Yes
Compatible With Anionic Surfactant (Soaps) No Yes No Yes Yes
Compatible With Non-Ionic Detergents Yes Yes Yes No Yes
Effectiveness in Presence of Organic Matter Good Very Poor Good Excellent Poor to Fair Good to Excellent
Detrimental Effects of Heat No Inactivated at >110° F. No No Inactivated at >110° F.
Most Effective pH Range Alkaline Acid Alkaline Neutral Neutral
Any Residue Action Yes Hypochlorites - No Chloramines - Yes Yes Yes Yes
Skin Irritation Properties Mild Moderate Mild Harsh Mild Non-irritating
Disadvantages - Inactive By Organic Debris Incompatible with Soaps, Limited Spectrum Strong Odor w/Coal & Wood Tar Distillate Expensive, Inactivated by Organic Debris Unreliable at Temperatures <65° F.


Keep Pigs Warm

Cold stress is a real stress on pigs. Observing how pigs are laying and behaving in their environment will help you understand if set points are correct. Normally, in nurseries and wean-to-finish barns, we provide mats in the zone heating area. This allows us to have the room a few degrees cooler. It is important that the pigs lie in the zone heating area. The creep mats are provided so a pig can utilize an area of the room with no updraft from the pit. The mats also provide a large feeding surface for the pigs the first week after weaning. Provide adequate mat space (.3-.5 sq. ft./pig) so all pigs can lie on it.

Table 4. Air Temperature (Varies by Pig Size, Pig Health & Season)
Nursery
Week Temperature (degrees F)
1 84°
2 82°
3 80°
4 78°
5 76°
6 74°
7 72°
8 70°
Finish
Week Temperature (degrees F)
1 72°
2 71°
3 70°
4 69°
5 68°
6 67°
7 66°
8 65°
9 64°
10 64°
11 64°
12 64°
13 64°
Wean-to-Finish
Week Temperature (degrees F)
1 84°
2 82°
3 80°
4 78°
5 76°
6 74°
7 72°
8 70°
9 69°
10 68°
11 67°
12 67°
13 66°
14 66°
15 65°
16 65°
17 64°


Keep Pigs Draft-Free

Keeping pigs draft-free is accomplished by providing the right air inlet speed so incoming air gets mixed with room air before falling onto the pigs. The standard goal is 700-800 ft./min. out of the inlets. This should be measured with a high-speed air meter to make sure inlets are set properly.

Other ways that pigs can be exposed to drafts is for air to come into the facility through curtain holes, door leaks or broken inlets, or having minimum ventilation rates set too high on the controller.

Keep Pigs Hydrated

Keeping pigs hydrated with fresh, clear and cool water to drink on a daily basis is extremely important. Warm water is a common problem that I see in the early nursery phase. Flushing the water lines several times a day for the first several days until pigs are drinking well is important to maintain water freshness and keep water cool.

Check the flow rates and make sure that pigs have easy access to water. Flow rate should be ½ to 1 qt./min. and water pressure in the lines should allow the weaned pig to depress the nipple easily without getting splashed in the face with high-pressure water.

Water smell and taste is a problem in many nurseries, too — especially where antibiotics have been used routinely for water medication. Clean the lines before pigs are brought in. Adding bleach or organic acids to the water lines can work well. Many of the organic acids can be used even with pigs in the facility.

The only way to know if water is a problem is by getting in the pen and checking the temperature, flow rate, smell and taste early in the turn to make sure there are no complications that will stress the pig. Water should be tested for coliforms by sending a sample to a lab to make sure your well has not been contaminated. Review the adjacent environmental checklist in Table 5 for guidelines.

Biosecurity

Biosecurity centers around the principle that you want to keep diseases out that you don't already have.

Figure 1 on page 34 provides a schematic drawing of potential sources of enteric pathogens on the hog farm.

The first obvious rule is to never allow pigs from outside the system in without a thorough health history and specific tests to prove that they carry no new disease.

Keep people out of the barns that do not belong there. And, make sure those who do enter the barns have been away from pigs at least overnight, and have nothing with them or on them that could carry enteric pathogens.

Require outside people and chore personnel to have specific farm boots and coveralls that are only worn in the barns. Service people will need to come to the barns for repairs on occasion. Make sure that they meet the downtime and biosecurity rules for your farm. They should be away from pigs at least overnight. Do not let them bring equipment that has been in other barns. If repair equipment is needed, make sure all items are cleaned, wiped down with a disinfectant and allowed to dry before entering the barns.

Table 5. Environmental Checklist
Humidity level:
50-65% relative humidity
Zone Heating:
Provide .3-.5 sq. ft./pig of mat space
90° F first 7-14 days
Inlet speed:
700-800 ft./min.
Feed quality:
Fresh — check bins and feeders
Quality — grind or pellet
Water Quality:
Fresh
Pressure — nursery & w/f = 8-10 lbs./sq. in.
Flow — ½ - 1 qt./min.
Taste and smell


A recent study by Sandy Amass, DVM, Purdue University, clearly demonstrated how easily enteric pathogens such as F18 E. coli are moved site to site by people. Simply washing hands or both changing clothes and washing hands did not stop the spread of F18 E. coli from infected pigs to non-infected pigs. Only a complete shower followed by a change of clothes stopped the E. coli.

We often see F18 E. coli in flows of pigs with no history of F18 E. coli in the facility or flow. Never underestimate people as vectors for this disease.

Keep birds, rodents and dogs and cats out of the barn. A bird screen must be maintained. A mouse baiting program must stay current.

In addition, feed spills and bin pads should be kept clean to avoid attracting birds and rodents. This is very important in the TGE season.

Trucking biosecurity needs to be reviewed often. Make sure you understand where your trucks are being washed, the standard operating procedures of that truck wash and the status of the last pigs hauled on the truck.

Also, be certain the driver is wearing clean boots and coveralls; store on the truck in a clean area. The cab of the truck should be inspected for cleanliness. It is not uncommon in the winter months to get TGE on a nursery or finish site about five days after pig entry due to truck contamination.

The rendering box area is key to biosecurity because it connects pig farms with dead pigs from the same geographic area. It is important that all farm workers follow procedures for using the rendering box. Develop a written protocol to include these rules:

  • Only go to the dead box at the end of the day;

  • Wear disposable boots if possible or wear specific boots that do not go back into the barn. All coveralls should be laundered after going to the dead box. The equipment to remove dead pigs from the barn should not go to the dead box area; and

  • There should be a line at the dead box that the barn and the rendering truck do not cross. The rendering driver should enter on one side and pigs should be delivered to the other side.



Treatments

If you suspect that your pigs have an enteric pathogen, seek veterinary assistance and get an accurate diagnosis so treatment can be targeted to the specific disease present.

Treatments revolve around killing the pathogen, keeping the pigs hydrated and creating an environment in the gastrointestinal tract that makes it difficult for the pathogen to multiply. Remember when pigs are acutely ill, their ability to eat feed or drink water containing antibiotics is limited.

Therefore, individual animal injections are important. But it is often difficult to spot every pig with diarrhea. Do a walk-through and count the number of loose stools per pen as a guide to decide if oral antibiotics should be administered.

In general, if there are greater than 3-5 loose stools per pen of 25-50 animals, water medication is probably advised.

Oral antibiotics for enteric diseases fall into two categories:

  1. Antibiotics that are in the gut and absorbed into the body, and

  2. Antibiotics that stay within the gut.



Review this information with your veterinarian, as some enteric diseases are confined to the intestinal tract only (ileitis), while others start in the gut but end up in the entire body (salmonella). Therefore, when treating with antibiotics, select those that are absorbed into the bloodstream. I often see enteric disease being treated with an antibiotic of little benefit to the condition.

Consult your veterinarian about specific drug choices for treatment of enteric disease. In general, good injectable choices include ceftiofur, tylosin and lincomycin. Good oral choices include neomycin, gentamicin and tiamulin. For viral enteric diseases (TGE, rotavirus), antibiotics will be ineffective unless there is a secondary bacterial infection. Often electrolytes help keep the pigs hydrated.

As with any infectious process in pigs, early detection and treatment are the keys. Nothing is more important than being with the pigs twice a day, and walking the barn in a manner that allows you to see every pig.

Prevention

Prevention centers on feed-grade products and oral vaccines to help control enteric infections in swine. Feed-grade products such as high levels of zinc, probiotics, immune products and acidifiers have all been used to decrease the organisms' abilities to multiply within the gastrointestinal tract. Feed-grade antibiotics fed at specific time frames in the grow-finish period have also been beneficial at reducing clinical disease. Oral vaccination with non-pathogenic live organisms has been very successful in reducing clinical disease for salmonella, E. coli and ileitis.

Summary

Management and control strategies for enteric diseases in swine involve basic principles that are not very complex. It is important to recognize management of pig flow, sanitation, environment and biosecurity as well as strategic vaccination and medication. All can play a huge role in the health of the pig in the nursery and grow-finish systems.

But it is the ability to actually implement these tools on a daily basis by discussing them, and having written protocols, that sets many farms apart from others, and allows them to be more profitable and enjoyable to work in.

COOL Bill Ill-Conceived

Legislation to streamline the current country-of-origin (COOL) law offered by Rep. Collin Peterson (D-MN) does little to solve problems and will still cost U.S. pork producers with no apparent benefits, says National Pork Producers Council (NPPC) President Jon Caspers.

“While the Peterson bill is an admirable attempt to fix the existing COOL law, it does nothing to address the fundamental concerns that pork producers have about this legislation,” says the NPPC leader. “The fact that this bill attempts to find a solution to this burdensome and costly law demonstrates that there are problems with it.”

Peterson's HR 3083 removes the current law's audit verification section and mandates the Agriculture Department to use existing producer records for compliance verification. Peterson's bill also bans third-party audits aimed at verifying producer compliance.

Bush Resolves Trade Deadlock

President Bush announced an agreement with the Russian Federation that will benefit pork producers' bottom lines by increasing the sale of pork products from the U.S. to Russia.

“The Russian Federation has taken numerous actions during the past few years that have negatively impacted U.S. pork producers and others in U.S. agriculture,” observes Jon Caspers, president of the National Pork Producers Council. “President Bush committed to resolve these problems and he delivered.

“Our producers were really harmed by Russia's restrictions on U.S. poultry exports. Russia is the U.S. poultry industry's number one export market, and the Russian restrictions backed up the poultry supply in the U.S. and brought down the prices of U.S. pork and live hogs,” he remarks. Russian restrictions on U.S. pork imports compounded the problem.

The administration's action sets a country-specific quota that will help shield U.S pork from dumped and subsidized pork exports from Brazil and the European Union to Russia.

Feeding to Enhance Swine Health

Many breakthroughs in swine nutrition research lead to improved digestion, and at the same time, eliminate or suppress the many bacterial and viral pathogens that cause enteric infections in pigs.

Increasing nutrient digestibility and maximizing feed intake are common ways promoting efficient gain, while limiting the impact of swine enteric disease in nursery and growing pigs. The results of these efforts at Kansas State University and elsewhere reflect the need for further research to unlock some of the remaining mysteries surrounding pig enteric health challenges.

Digestion

After digestion in the stomach, further digestion and a large portion of the absorption of fat, protein, carbohydrates, vitamins and minerals occur in the small intestine. In the large intestine, there is very little direct nutrient absorption except water and electrolytes.

However, there is a large bacterial population that ferments undigested carbohydrate, fat, and protein into short chain fatty acids. Some of these fatty acids are then absorbed and utilized as an energy source. Undigested carbohydrate consisting of plant cell wall remnants, bacterial particles and other unabsorbed nutrients are then voided as fecal matter. This undigested carbohydrate is commonly termed as non-starch polysaccharides or “dietary fiber.”

Feeding Fiber

Consultants commonly recommend the addition of dietary fiber to swine diets to aid in controlling swine enteric disease. This includes using oat products in nursery diets, and wheat bran, soy hulls or dried distillers grains to control porcine proliferative enteritis (ileitis) and colitis.

It appears that there are two primary drivers of these recommendations. The first is European research from the 1960s and 1970s evaluating low-crude protein and high-insoluble fiber diets for the prevention of death loss associated with postweaning Escherichia colibacillosis (E. coli).

Unfortunately, these diets were only effective after feeding a high enough proportion of the low-crude protein and high-fiber diet to severely restrict growth rate. Intermediate levels of crude protein and fiber were not successful in preventing E. coli-associated death loss.

Still, this research is the common basis for adding fiber to the diet and lowering nutrient content.

Dietary Advances in Fiber

Since the studies were conducted, there have been many major developments in diet formulation for nursery pigs. These include the use of highly digestible lactose sources and animal proteins and the management of the negative effects of the immune response to soybean protein antigens.

Additionally, the development of segregated batch pig production and implementation of improved hygiene procedures have led to better nursery pig performance and disease control.

Recommendations to add fiber to pig diets to control enteric disease are also based on widely documented benefits of including dietary fiber in human diets. These benefits include the role fiber plays in altering the microbial population to help stimulate growth of colon cells and lymphoid tissue.

However, the average adult human intake of dietary fiber is 15 to 20 g./day, compared to a recommended intake of 30 to 35 g./day.

In contrast, a finishing pig eating a corn-soy diet is consuming approximately 250 g./day of dietary fiber. Simple corn-soybean meal-based diets should contain more than adequate amounts of fiber to stimulate growth of the enteric cells. Thus, documentation from human literature should be applied to the pig with caution.

Nonetheless, addition of fiber to swine diets continues to be a widely promoted practice to control swine enteric disease.

Fiber is defined as the plant cell wall components that are left over after enzymes break down starch, fat and protein. Thus, there is a direct, negative correlation between dietary fiber content and energy value. This correlation indicates that as fiber content increases, the ability of the pig to utilize the energy of the feedstuff decreases (Figure 1). Fiber also produces negative effects on amino acid and fat digestibility.

Fiber Research

Recent research suggests that increasing the digestibility of the diet by reducing the amount of soluble fiber also reduces the proliferation of infectious E. coli organisms. These fiber sources increase the viscosity of the digestive system, seemingly providing a microenvironment in the small intestine to allow for the proliferation of the E. coli.

Spirochete-Associated Colitis

Spirochete colitis associated with Brachyspira hyodysentariae causing swine dysentery, and Brachyspira pilosicoli causing porcine colonic spirochetosis, are known to trigger diarrhea in growing pigs. Environmental management and the use of antimicrobials have been the primary means of disease control.

But research efforts suggest dietary changes can greatly influence clinical disease associated with these spirochete (slender, undulating bacteria) organisms.

Swine dysentery challenge studies completed in Australia, utilizing highly digestible cooked rice and animal protein diets, have demonstrated a significant reduction in colonization and clinical disease. Highly digestible feedstuffs minimize readily fermentable material entering the colon.

Conversely, pigs consuming diets with higher levels of non-starch polysaccharides (hemi-cellulose, pectins, lignins) and resistant starches showed greater clinical signs of swine dysentery. These diets resulted in a greater amount of fermentable material entering the large intestine. The spiral colons of pigs on the highly digestible diets also tended to have a reduced hindgut (back part of the alimentary canal which extends from the mouth to the anus) organ mass and lumen contents. Finally, the large intestine and fecal material contained less water in the pigs fed highly digestible diets.

Disease Challenge Study

In a colonic spirochetosis challenge study, which evaluates the influence of diet on clinical disease, similar findings were demonstrated. This study compared the effect of feeding diets with varying degrees of digestibility (corn-animal protein, corn-soybean, and wheat-barley-soybean diets) to weaned pigs challenged with porcine colonic spirochetosis. The corn-soybean diet was designed to cause a delayed-type hypersensitivity reaction in the small intestine, leading to temporarily poor absorption and an increase in fermentable material into the colon. The impact on hindgut pH and volatile fatty acid production was similar to the previous studies.

The clinical disease and extent of severity of the lesions were reduced in pigs fed the more highly digestible, corn-animal protein diets. While there were no significant differences in growth rate, this experiment illustrates that dietary composition definitely has an effect on factors in the microenvironment of the colon that are conducive to disease promotion.

These evaluations indicate that the volume of rapidly fermentable material entering the hindgut leads to elevated volatile fatty acid production and a lower pH, which seems to promote spirochete growth.

These findings may indicate that other factors leading to incomplete, small intestinal digestion likely enhance the susceptibility to spirochete-associated colitis. Predisposing factors such as bacterial or viral enteritis, stress, dietary transitions or high-fiber diets may lead to an increased level of fermentable material entering the hindgut, which enhances the pig's susceptibility to spirochete colitis. It is not known if the altered hindgut environment has a direct effect on these two spirochete pathogens.

Salmonellosis

Feed has long been implicated as a possible source of salmonella contamination. Therefore, heat treatment such as pelleting has been advocated for reducing feed-related salmonella infection. Reduction in salmonella infection has been associated with feeding pelleted rations in poultry even though salmonella was not detected in raw ingredients.

However, swine survey information points to pelleted feeds as posing a significant risk for salmonella. It is not known if these results are due to delivery of contaminated feed or an effect of the pellet diet on factors that promote salmonella growth in the intestine. Current research at Kansas State University seems to indicate that in corn-based diets, there is little impact of pellet or grain particle size on salmonella shedding.

Parasitism

Recent research has indicated that a diet with high carbohydrate digestibility decreases strongyloid nematode parasite establishment, size and female ability to reproduce. In contrast, a diet high in non-starch polysaccharides provides favorable conditions for parasite establishment and sustainability.

This work is further supported by an epidemiological study indicating that in herds positive for ascarid roundworms and trichinae eggs, much higher levels of insoluble, non-starch polysaccharides and total, non-starch polysaccharides were being fed.

Soybean Meal in Young Pig Diets

The source and percentage of soybean protein in diets for early weaned pigs have been controversial subjects among swine nutritionists. The controversy is due to the implication that soy protein causes a temporary hypersensitivity in the early weaned pig.

Briefly, the hypersensitivity response occurs three to four days after exposure to adequate soy proteins. The temporary hypersensitivity results in digestive abnormalities, including disorders in digestive movement and inflammatory responses in the intestinal mucosa or mucous membrane. Villi (fingerlike projections of the intestine) are sloughed or cast off from the small intestinal mucosa; absorption abilities are reduced and susceptibility to enteric toxins and bacterial infections are increased.

Although the exact mechanisms are not known, these changes are thought to be the result of antigen-antibody complexes that initiate the pig's own immune system to produce cytokines (cells that produce immunity) and complement (proteins that destroy bacteria). The cytokines and complement are thought to directly cause the damage to the intestinal mucosa.

Most importantly, these changes result in reduced growth performance. Recovery occurs after seven to 10 days when oral immune tolerance begins to develop and, eventually, the intestinal mucosa returns to normal with little evidence of long-term damage.

One approach used successfully to reduce the negative effects of the temporary digestive problems is to carefully select high-quality, digestible protein and carbohydrate sources while increasing the amount of soybean meal in each subsequent diet. Exposing young pigs to increasing levels of soybean meal in each diet will allow them to overcome the hypersensitivity to soy protein more quickly, without causing a long-term reduction in performance.

That early exposure permits inclusion of soybean meal at higher levels in future diets without reducing growth performance. This approach has consistently proven more economical than delaying exposure to soybean meal.

Restricting Feed Intake Study

A large epidemiological study, designed to assess the risk of several factors related to nursery pig enteric disease, indicated that restricting feed intake was the most important risk factor linked to increased amounts of enteric disease in the nursery (Figure 2).

This data showed that as feed intake increased during the first week postweaning, growth rates improved and diarrhea cases declined.

As shown in Figure 2, farms for which average feed consumption was less than 0.33 lb./day in the first seven days after weaning had 33.6 times greater risk of diarrhea than those farms in which feed consumption was 0.44-0.55 lb./day in the first seven days after weaning. Also, note that farms having an intermediate level of feed consumption (0.33-0.44 lb./day) had 18.6 times greater risk for diarrhea than those consuming the higher amount of feed. Thus, farms that practiced restriction of feed intake in the first week after weaning were more likely to have enteric disease problems and slow nursery growth rates.

Proper Feed Management

The scientific evidence suggests adding fiber or restricting feed intake are contrary to a significant body of science describing the biology and epidemiology of controlling enteric disease.

However, maximizing feed intake does not mean that feeders should be left wide open with excessive amounts of feed in the feed pan. We continually observe decreased growth rate as a result of improper feeder adjustment.

In an attempt to stimulate feeding behavior, large amounts of the first diet are placed in the feeding pan. Although the intention is correct, the outcome is negative. Pigs “sort” the diet, which causes a buildup of fines in the feeding pan. These fines then lodge in the feed agitator mechanism, making it difficult for new feed to flow from the feeder. This problem is remedied by decreasing the amount of feed flow in the pan to stimulate development of feeding behavior.

Approximately 25% to 50% of the bottom of the feeding pan should be visible in the first few days after weaning. As the pigs become more accustomed to the location of the feed and adjust feeding behavior, the amount of feed in the feeding pan should be decreased rapidly to 25% or less coverage. Also, feed agitators need to be tested frequently to ensure that the buildup of fines does not prevent them from working freely.

Practical Recommendations

  • Use good veterinary diagnostics to determine if a primary pathogen is present. Some 92.9% of farms from one study with a clinical diagnosis of “non-specific colitis” actually had infections with known, enteric pathogens after proper diagnostic investigation was performed.

  • Evaluate environmental cleaning practices. Poor sanitation practices have been shown to be a significant risk factor for in-creased enteric disease.



Four Steps To Curb Feedstuffs Problems

  1. Evaluate processing techniques; grain particle size should be in the 600 to 800 micron range, which reduces the amount of undigested material entering the large intestine.

  2. Change to cereal grains with higher starch content and less non-starch polysaccharides. This change includes corn, milo or wheat from barley, oat or by-products.

  3. Change protein source from canola to soybean meal.

  4. Limit use of higher fiber containing feedstuffs such as soy hulls and wheat middlings.


Market Factors Blunt Profit Prospects

Several market factors threaten to moderate pork profit prospects for the rest of 2003 and into 2004, says Purdue University agricultural economist Chris Hurt.

“Now the outlook is for modest losses this fall and winter, with some very small profits next spring and summer,” he says. “The negative market factors include the increased flow of hogs and pork from Canada, due to the restriction of (Canadian) beef imports, and higher corn and soybean meal prices than had been anticipated a few months ago.”

Last year, Canada supplied 5.9% of total U.S. hog slaughter. This year, that figure will be closer to 6.5%, with total live imports this summer at over 8% of U.S. hog slaughter, says Hurt.

Processed pork imports from Canada this year are up 16% through summer.

Hog numbers and pork supplies will be slightly higher than earlier forecast, based on the September Hogs and Pigs report. The breeding herd was down 3%, but the summer pig crop was only down 2%. Fall farrowings will only be off 1%, while winter intentions are unchanged, says Hurt.

Hurt projects fall live hog prices at $36-40/cwt., winter prices $1 higher and spring and summer 2004 prices at $39-44/cwt.

Producer Plant Sets Opening

Meadowbrook Farms Cooperative is moving ahead with plans to open a $25 million packing plant for its 200 producer members at Rantoul, IL, in early November, says company spokesman Jim Altemus.

On Oct. 28, the cooperative will hold its annual membership meeting. At that time, producer members will have the chance to see state-of-the art equipment perform a test run of cutting and packaging pork products.

On Oct. 29, a media session is planned for 9 a.m. to 2 p.m., followed by an open house for the public, says Altemus.

The cooperative will employ 215-220 workers in its 3,000-head, single-shift, pork packing and processing facility.