4 Vaccines and Vaccinations: Production Animals

As in small animals, side-effects can occur with vaccination in cattle. These include soreness/swelling/knots at the injection site, fever, off-feed, and potentially anaphylaxis (allergic reactions). “Endotoxin stacking,” the act of giving multiple killed bacterin vaccines (often Gram negative or Gram negative-like) vaccines together, has been associated with higher incidence of adverse reactions, failed immune response, and death.To minimize vaccine risks:

• Avoid the administration of more than two killed bacterin vaccines at the same time
• Do not shake killed bacterial vaccine such as clostridial (black-leg) products
• Never vaccinate on days where cattle are heat stressed
• Store vaccines properly
  • 35-45^oF, DO NOT FREEZE, and avoid sunlight
• Administer with proper care
• Only use licensed, quality vaccines

Beef Quality Assurance Vaccination Administration Guidelines

Any injection has the ability to cause a detectable lesion at slaughter. Beef Quality Assurance programs offer guidelines in proper administration of injectable products with the goal of maintaining and increasing the quality of the end product.Some general recommendations include:

• Use vaccines labeled for subcutaneous route of administration whenever possible.
• Administer all vaccines in the neck region.
• Inject in a clean site.
• Replace needles frequently or use single use needles.
• Use an appropriately sized needle for the intended injection route.
• Use good sanitation when withdrawing vaccines.
• Use properly cleaned and maintained syringes.

 

Diseases to Vaccinate Against in Beef and Dairy Cattle

Diseases in beef and dairy cattle to vaccinate against, include:

• Bovine viral diarrhea (BVD)
• Infectious bovine rhinotracheitis (IBR)
• Parainfluenza (PI3)
• Bovine respiratory disease complex
• Leptospirosis
• Campylobacter
• Clostridial diseases
• Brucellosis

Bovine Viral Diarrhea

BVD is a common cause of respiratory and reproductive issues in the herd. It is an economically important disease in many countries. The disease is caused by the bovine viral diarrhea virus, which may cause primary disease or be part of a large complex of infections. Cows infected during pregnancy may abort, give birth to a stillborn calf, or give birth to a live calf. Calves can be infected in utero or after birth. Calves born carrying BVD virus will never clear the infection and will shed the virus continuously into the farm environment. Signs of BVD in adults are highly variable and include fever, lethargy, loss of appetite, ocular discharge, nasal discharge, diarrhea, and decreased milk production. Infected calves may have cerebellar hypoplasia; signs of this are ataxia, tremors, a wide stance, and failure to nurse.

Infectious Bovine Rhinotracheitis

IBR is a highly contagious, infectious respiratory disease that is caused by bovine herpesvirus I. It can affect young and older cattle. IBR causes acute inflammation of the respiratory tract; clinical signs include those of respiratory disease (mucosal hyperemia, erosive mucosal lesions, nasal discharge, coughing), and also conjunctivitis, abortion, and encephalitis. After the first infection, the virus is sequestered in neurons in the brain as a latent infection. At times of stress, the virus undergoes recrudescence and can be shed from the eyes and nose. Because an infected animal never clears the virus, animals that are seropositive for bovine herpesvirus 1 cannot be shipped into countries that are free of the disease and cannot be housed in artificial insemination (AI) centers. Carrier cattle should be identified and removed from the herd.

Parainfluenza

The PI3 virus infects the upper respiratory mucosa, where it is shed in aerosols (sneezing and coughing) and by direct contact. PI3 causes only respiratory disease. In mature cattle, infection is mild. The most important consequence of PI3 infection in bovine respiratory disease is that it predisposes animals to concurrent infection with IBR or bacterial respiratory pathogens.

Bovine Respiratory Disease Complex

Bovine respiratory disease complex is caused by a variety of pathogens, including the three above. Other organisms against which cattle may be vaccinated to minimize this disease complex are bovine respiratory syncytial virus (BRSV) and bacteria including Pasteurella multocida, Mannheimia haemolytica, and Histophilus (formerly Hemophilus) somnus. These pathogens interact with each other to cause disease. Disease is worsened in the presence of stressors including parasites, weaning, change of feed, variation in ambient temperature and humidity, and weather.  Clinical signs depend on age of the animal, organism(s) involved, and stage of the disease. Bovine respiratory disease is closely linked with fever; it is one of the most common causes of fever in cattle and fever may be the first sign of disease in affected cattle. Other signs include mental dullness, lack of appetite, rapid shallow breathing, and discharge from the nose and eyes (watery to purulent to bloody). Coughing will be mild and tentative early in the disease course and prominent (“honking”) later in the disease course.

Leptospirosis

Leptospirosis is a zoonotic disease, caused by bacteria of the genus Leptospira. There are many different serotypes of disease and prevalence varies with geographic location. Serovars include hardjo-bovis, pomona, canicola, icterohaemmorhagiae, and grippotyphosa. Maintenance hosts, also called reservoir hosts, carry the bacteria and are a source of exposure to other susceptible animals. Maintenance hosts for leptospirosis include cattle, pigs, dogs, raccoons, skunks, and rodents. Animals can be infected by serovars maintained by their own species (host-adapted infection) or by serovars maintained by other species (non-host-adapted infection). Leptospirosis can be transmitted either directly between animals or indirectly, through the environment. Cattle are the maintenance hosts for L. hardo-bovis; disease in cattle with this serovar is less severe but can have a significant economic impact. Cattle infected with other seorvars, especially L. pomona, suffer more severe illness. Clinical signs vary with the herd’s degree of resistance or immunity, the infecting serovar, and the age of the animal infected. Host-adapted infections in cattle can occur in animals of any age and mainly affect fertility and the renal system. Infected cattle may shed the organism in their urine for weeks to months. Non-host-adapted infection in cattle is typically due to L. pomona and mainly affects the hemolymphatic, urinary, and reproductive systems. Acute disease is characterized by hemolytic anemia, which causes red urine and jaundice. Reproductive effects include infertility, stillbirths, and abortion 1-3 months after infection. Lactating cows may suffer from mastitis, with decreased production and milk that is thick and yellow.

Campylobacter

Campylobacteriosis, formerly called Vibriosis, is caused by the bacterium Campylobacter fetus and is spread by infected bulls when they mate with susceptible cows and heifers. Once infected, a bull remains an asymptomatic carrier of the condition. Transmission is venereal; non-venereal transmission is unlikely to occur. When introduced to a herd the disease spreads rapidly because the cows and heifers have no immunity. Conception rates drop to around 40%. As immunity develops, the disease rate drops but reinfection often occurs as immunity wanes about a year after the initial infection. Conception rates in chronically infected herds are usually between 65 and 75%, with replacement heifers (newly introduced animals) being most severely affected. The infection can prevent implantation of a fertilized egg in the uterine lining, or more commonly, causes death of the developing embryo. When the embryo is lost, the cow goes back into heat and usually can be rebred successfully, since she has now developed immunity. Occasionally the disease results in permanent infertility.

Clostridial Diseases

Clostridial diseases strike cattle suddenly, often causing death before any clinical signs are seen. The bacteria that cause these diseases create very long-lived spores that are found everywhere in the environment and can easily be picked up by grazing cattle or enter the body through a wound. Bacteria may live in the gastrointestinal tract and spores also may be present in the tissues of healthy animals. Not all species of Clostridium cause disease but those that do usually are fatal. Examples include:

• C. septicum – malignant edema
• C. chauvoei – blackleg
• C. perfringens types A, B, C, and D – enterotoxemia
• C. tetani – tetanus
• C. botulinum – botulism

Contributing factors are necessary to allow the bacteria to multiply and cause disease. This may include injury or invasive procedures such as surgery, giving birth (parturition), or puncture wounds. Diet changes, overeating, and acidosis may permit clostridial organisms in the gut to multiply and cause disease. Clinical signs differ depending on the specific organism and may include sudden death in apparently healthy animals, lethargy or depression, high fever, anorexia, localized stiffness or muscle spasms, port wine colored urine, acute lameness and swelling in the hips and shoulders with a crackling sound when the skin is pressed (blackleg), or flaccid paralysis (botulism).

Brucellosis

Brucellosis is an infectious disease that spreads between animal species and between animals and humans. In cattle, the bacterium involved usually is Brucella abortus. Brucellosis is highly contagious, spreading very easily between cattle. The primary clinical sign is late-term abortion and the aborted calf, membranes, and fluids all contain large numbers of bacteria.

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    Small Ruminants

Vaccination Methods

Vaccines cannot replace good management practices. When vaccinating sheep and goats, make sure they are healthy animals, and that the injection site is clean and dry to prevent introducing infection with your injection. Make sure you have adequate handling facilities such as a properly constructed chute or pen. When vaccinating multiple animals using an automatic syringe, verify that the correct dose is being administered. Needles should be changed every 12-20 animals (generally every pen or chute-full) and anytime the needle is dull, burred, or bent. Some facilities will be part of specific disease-control programs (caprine arthritis encephalitis virus (CAE) or ovine progressive pneumonia (OPP)); in that instance, multi-dose syringes may be used but a new needle must be used for each animal. In general, 18 gauge 5/8” needles are used for adult animals and 20 gauge 1/2 to 5/8” needles are used for young animals. Make sure all animals are individually identified (tags, tattoos) and that there is a system for record keeping so you know which animals received which vaccines.

To vaccinate, part the wool if necessary, raise the skin to form a tent and insert the needle into the tent opening so that the needle is almost parallel with the neck. The site of injection is important if the animal you are vaccinating is to be used for food. Vaccines are given so as to minimize carcass and hide degradation due to abscess or scar formation. Vaccines should be given subcutaneously in the neck region or in the ventral aspect of the axillary space. The meat from these regions is of low value and pelt damage in these areas easily can be trimmed with minimal effect on value. Injection over the ribs is not optimal but it can be used if the animal cannot be restrained to allow you to use another location.

How to Vaccinate Sheep and Goats

Which vaccines are used depends on:

• History at the individual farm
• Age of the sheep or goats
• Previous disease problems
• Open or closed flock/herd status – are animals coming and going for shows, purchases, breeding?
• Geographic region
• Soil type
• Diet and flock/herd economics
• Withdrawal time (refer to the label!)

To choose vaccines, consider:

• Real and high-likelihood risks
  • Since all ruminants are at risk for Clostridium perfringens type D, toxoid against this agent ideally should be used in all sheep flocks and goat herds
  • Show animals have considerable exposure to contagious ecthyma virus (soremouth) and caseous lymphadenitis
  • Open flocks have exposure to foot rot and abortion diseases
• All animals should be vaccinated with:
  • CD-T vaccine – Clostridium perfringens is more commonly called enterotoxemia or overeating disease.  Type C primarily affects lambs and kids during their first few weeks of life.  Type D (pulpy kidney disease) affects lambs and kids that are usually over a month of age, particularly those that are creep-fed or finished on concentrate diets. Clostridium tetani is the causative agent of tetanus. CD-T toxoid is the vaccine usually used to protect healthy sheep and goats against these clostridial diseases.
• Most animals should be vaccinated against Campylobacter and Chlamydophila (abortion diseases) and contagious ecthyma (soremouth).
• Some animals should be vaccinated against contagious lymphadenitis and rabies and even more rarely, against E. coli, bluetongue virus, and Brucella ovis.
• Some people recommend use of cattle or equine vaccines in small ruminants but they are not labeled for this use and efficacy has not been well demonstrated.

Diseases in Sheep and Goats

Diseases to be vaccinated against in sheep and goats include:

• Clostridial diseases
• Abortion diseases in sheep
• Contagious ecthyma (soremouth, orf, scabby mouth or pustular dermatitis
• Caseous lymphadenitis (CLA, boils, abscesses or cheesy gland)

Clostridial Diseases

Clostridial organisms of various types are found in the soil, where they can survive for a very long time. Most clostridial organisms also survive naturally in the gastrointestinal tract of healthy animals. Sheep can be infected with various clostridial diseases (see diseases in cattle) but the most common are enterotoxemia types C and D and tetanus. Enterotoxemia type C (hemorrhagic enteritis or bloody scours) is caused by Clostridium perfringens type C and affects lambs during their first few weeks of life, causing a bloody infection of the small intestine. It is often related to indigestion and is predisposed by a sudden change in feed, for example an increase in the dam’s milk supply or beginning creep feeding as lambs are being weaned. Enterotoxemia type D (overeating disease or pulpy kidney disease) is caused by Clostridium perfringens type D and commonly strikes the largest, fastest growing lambs in the flock. It is caused by a sudden change in the feed that causes the organism, which is already present in the lamb’s gastrointestinal tract, to proliferate, causing a toxic reaction. It is most common in lambs that are on high concentrate rations but can also occur when lambs are nursing from dams that are heavy milkers. It usually affects lambs over one month of age. Sudden death may be the first sign. Other clinical manifestations include neurologic signs, seizures, and diarrhea. Tetanus is caused by Clostridium tetani, a soil inhabitant that is a prolific spore producer. This disease is usually related to tail docking and castration, although any wound can harbor the tetanus organism. Signs of tetanus occur from about 4 days to 3 weeks or longer after infection is established in a wound. The animal may have a stiff gait, lockjaw can develop, and the third eyelid may protrude across the eye. The animal usually will go down with all four legs held out straight and stiff and the head drawn back. Convulsions may occur.

Abortion Diseases 

Ewes or does that lose their lambs early in pregnancy may not return to heat because they are seasonal breeders, and so may not be bred back that season. This is a significant loss for the producer both because of decreased lamb crop and because those dams will not lactate that season. Pregnancy also may be lost late in gestation or weak or deformed lambs may be born. For many diseases causing abortion in small ruminants, there is no vaccine in the United States (for example, Q fever, toxoplasmosis, Border disease). In the United States, the most common causes of abortion in ewes are Chlamydia / Chlamydophila (enzootic abortion) and Campylobacter. Enzootic abortion is transmitted from aborting dams to other females in the flock. Ewe lambs are the most susceptible on farms where the organism is present. Abortion usually is seen late in pregnancy or lambs may be born that die shortly after birth. Campylobacteriosis (formerly called Vibriosis) causes abortion late in pregnancy or birth of stillborn or weak lambs. Infecting organisms are Campylobacter jejuni and Campylobacter fetus. Ewes are infected orally and the incubation time from ingestion to abortion is just 2 weeks.

Contagious Ecthyma (soremouth, orf, scabby mouth, or pustular dermatitis)

Soremouth is the most common skin disease affecting sheep and goats. It is a highly contagious viral infection that also can produce painful infections in humans. The virus causes scab formation on the skin, usually around the mouth, nostrils, eyes, mammary glands, and vulva. It first appears as tiny red nodules, usually at the junctions of the lips.

Caseous Lymphadenitis (CLA, boils, abscesses, or cheesy gland)

Caseous lymphadenitis is an infectious, contagious disease that primarily infects the lymphatic system, though other organs can be affected. It is caused by Corynebacterium pseudotuberculosis. Infection results in abscess formation in the lymph nodes that when cut or ruptured, discharge pus containing the bacteria in the surroundings. When the infection spreads internally, affected animals slowly lose weight and eventually become emaciated.

Vaccines for Disease in Sheep and Goats

Specific vaccines that are available are:

• CD-T (Clostridium perfringens types C and D and tetanus toxoid)
• Abortion vaccines
• Contagious ecthyma (soremouth, orf)
• Caseous lymphadenitis (CLA)
• Rabies

CD-T (Clostridium perfringens types C and D and tetanus toxoid)

Protection against type C is needed by nursing lambs and kids on all farms, regardless of management practices. Maternal antibodies will be present in colostrum if the ewe/doe was vaccinated in the 2-4 weeks prior to parturition. This passive immunity lasts in the lamb/kid for their first 50-60 days of life. Protection against type D is needed in lambs/kids fed grain or lush forage (any high-carbohydrate diet). It is associated with production of a toxin that is acutely fatal in fast-growing lambs. Tetanus toxoid is included in this product. Ewes and does should be vaccinated 8 weeks prior to the first time they give birth, and boostered at 2-4 weeks prior to parturition. Previously vaccinated ewes and does only require the vaccination 2-4 weeks prior to parturition. Offspring from vaccinated dams are vaccinated at weaning and again 3-4 weeks later. Offspring from unvaccinated dams are vaccinated as newborns (may have systemic reaction, can be treated with epinephrine) and are boostered at 3-4 weeks of age and again at weaning. All animals, including males, should be boostered at least annually; some goats may only maintain protective antibody titers for six months after vaccination.

Abortion Vaccines

In general, do not vaccinate if there are no problems on the farm or if animals are determined to be at low risk. Risk is associated with having an open flock, with animal traffic on and off the farm, with free-roaming wildlife, feeding on the ground, or with a history of abortions in the flock. Diagnosis for abortion problems is difficult and for many diseases causing abortion in small ruminants, there is no vaccine in the United States (for example, Q fever, toxoplasmosis, Border disease).

• Chlamydia / Chlamydophila (enzootic abortion) vaccine may not be effective against all strains causing abortions and regional variations in protection may exist. The label states that the vaccine should be administered 60 days prior to breeding with a booster in 30 days.
• Campylobacter (formerly called Vibrio) vaccination induces immunity for only 4-5 months. The label states that the first dose of vaccine should be given 2 weeks prior to breeding and that it should be boostered 2-3 months later. In the face of an “abortion storm,” where many abortions are occurring in the flock due to this organism, revaccination of all animals may reduce losses.

Contagious Ecthyma (soremouth, orf)

This is a live virus vaccine that will introduce a mild infection. This vaccine should only be used if this disease is present in the flock. The vaccine is given percutaneously; an area of skin in a wool-less region (inside the thigh or ear, or under the tail) is scarified in the form of an X deeply enough to cause inflammation but not so deeply as to cause bleeding. The vaccine is brushed on. The vaccinated area will scab over and does contain live virus that will be infective even after falling off the sheep. Vaccination under the tail is preferred to that inside the thigh, as vaccination on the medial thigh region may cause irritation and scabbing over the mammary glands and teats. This is a zoonotic disease so people should wear gloves and exercise caution when handling the vaccine or sheep, or picking up scabs. On farms that have a problem with this disorder, each new lamb and kid crop should be vaccinated. Lambs moving into feedlots should be vaccinated at least 14 days before shipment. Do not use this vaccine on farms that do not already have this disorder.

Caseous Lymphadenitis (CLA)

This may be a stand-alone vaccine or combined with CD-T vaccine. Vaccination decreases severity of disease but does not prevent disease. The vaccine should not be used in flocks or herds unless they have been exposed or contain affected individuals.

Rabies

This is a killed vaccine. Several products are available for sheep. No products are specifically labeled for goats but there is a recommendation in some situations that publicly displayed goats will be vaccinated. For example, goats take to a show that will be housed in a pen probably will not be vaccinated for rabies, while goats at a petting zoo that are purposefully brought to that site to interact with people will be vaccinated for rabies. Animals are vaccinated when greater than 3 months of age and then annually.

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    SWINE

Vaccination is a common preventive medicine practice on commercial swine farms. Vaccination protocols for swine typically focus upon preventing diseases of the reproductive, respiratory, and gastrointestinal tracts, and preventing multi-systemic disease. Vaccines may be applied to the reproductive herd (sows and boars), replacement females (gilts), or growing pigs, depending on when the disease challenge is expected.

Routes of administration for swine vaccines typically include IM  or oral (per os = PO). Multivalent vaccines (those containing multiple organisms) are commonly created to decrease the stress, labor, and food safety issues associated with multiple injections. Swine farm clientele expect that veterinarians will consider the costs and benefits associated with the vaccination protocols they recommend.

Diseases in Swine

Diseases to vaccinate against in swine include:

• Leptospirosis
• Erysipelas
• Porcine parvovirus (PPV)
• Porcine Reproductive and Respiratory Syndrome (PRRS)
• Mycoplasma hyopneumoniae
• Influenza
• Escherichia coli
• Rotavirus
• Porcine Proliferative Enteritis (PPE)
• Porcine Circovirus Type 2 (PCV2)
• Meningitis

Leptospirosis

As in cattle, leptospirosis is a zoonotic disease, caused by bacteria of the genus Leptospira. There are many different serotypes of disease and prevalence varies with geographic location. Worldwide, pigs are the maintenance hosts for pomona, tarassovi, bratislava, and muenchen.  Pomona causes important reproductive problems in breeding sows, spreading slowly through the herd. The skunk is a reservoir host. Once the organism is introduced into a herd, the pigs become permanent carriers with infection of the kidneys and intermittent excretion of the organism into the urine. Piglets rarely are infected. The most common manifestation is chronic low-grade disease in sows, with abortions, stillbirths, and birth of weak piglets.

Erysipelas

Swine erysipelas is caused by a bacterium, Erysipelothrix rhusiopathiae, that is found on most if not all pig farms. Up to half of the animals on a farm may carry it in their tonsils. It is excreted in saliva, feces, and urine, and so is common in the environment. It is also found in many other species, including birds, and can survive for long periods in the environment. The bacterium alone may cause disease but clinical disease is more common if there is concurrent infection with viral diseases such as porcine reproductive and respiratory syndrome (PRRS) virus and influenza. Disease is relatively uncommon in pigs under 8-12 weeks of age due to protection provided by maternal antibodies from colostrum. The most susceptible animals are growing pigs, non-vaccinated gilts, and young sows. Infected sows may show acute death in apparently healthy animals, fever, abortion, stillbirths, birth of mummified piglets, raised areas in the skin (“diamonds”) that turn red and then black, or joint stiffness. Infertility may be a presenting concern on a farm. Infected boars with high fevers have transient decrease in semen quality, reflected as sows not getting pregnant or having smaller litters. Infected growing pigs may show acute death, fever, and the characteristic skin lesion described above.

Porcine Parvovirus (PPV)

PPV is the most common and important cause of infectious infertility in pigs. Porcine parvovirus multiplies normally in the intestine of the pig without causing clinical signs. It is worldwide in its distribution. PPV can persist in the environment for many months and is resistant to most disinfectants. Infected sows show only reproductive signs of disease. Parvovirus is associated with lack of conception, birth of mummified or stillborn pigs, and birth of live pigs with low birth weight.  Sporadic disease is seen in individual females that are infected for the first time; for this reason, disease usually is seen in gilts. Once a pig is exposed, it has lifelong immunity. Reproductive problems in a herd appear about every 3-4 years if vaccination is not practiced.

Porcine Reproductive and Respiratory Syndrome (PRRS)

This is a fairly new disease; it has only been recognized in the United States since the mid-1980s and was only identified as being caused by an arterivirus in 1991. The virus has an affinity for macrophages, especially those in the lung. Up to 40% of macrophages are destroyed in a given animal, making it susceptible to other diseases. When introduced into a new herd, 90% of breeding sows will be seropositive within 4-5 months. Grower pigs shed virus for months; adult pigs shed virus for periods of time as short as 2 weeks. Nasal secretions, saliva, feces, and urine may contain virus. The virus can be airborne for up to 2 miles and can be carried between pigs and on fomites (inanimate objects) including boots, equipment, and trucks. The virus also may be carried by flies and mosquitoes. The clinical picture varies tremendously from one herd to another. As a guide, for every three herds that are exposed to PRRS for the first time, one will show no recognizable disease, the second will show mild disease, and the third will show moderate to severe disease. The reasons for this are not clearly understood. Clinical signs in sows include inappetance; fever; abortions; early farrowing with birth of mummified, stillborn, or weak pigs; prolonged return to heat after weaning of piglets; coughing; lack of milk and mastitis; lethargy; and cyanosis (blue discoloration) of the ears. This is the acute phase of the disease. Long-term, reproductive efficiency in herds in which the infection has become enzootic are associated with 10-15% reduction in farrowing rate, increased stillbirths, increased number of abortions, and inappetance in sows at farrowing. Infected piglets may show diarrhea and increase in other respiratory infections. Infected weaning and growing pigs may show other infections secondary to PRRS infection with a variety of clinical signs and mortality rate as high as 12-15%.

Mycoplasma hyopneumoniae

This is one of the most important contributors to respiratory disease in pigs. The organism damages the cilia and epithelia of the airways of the lower respiratory tract, permitting infection with other organisms, for example PRRS virus. Mycoplasma is transmitted via direct contact with infected pigs. Pigs older than 6 weeks are mainly those affected. Clinical signs include a non-productive cough, rough hair coat, and reduced growth rate and feed efficiency. With secondary bacterial infection, signs are more severe and include labored breathing, a harsher cough, fever, and prostration.

Influenza

Influenza viruses are the cause of outbreaks of acute respiratory disease. Influenza A viruses infect a wide range of avian and mammalian species, with the latter group including humans, pigs, horses, and aquatic mammals. Type A viruses are known for their ability to change their antigenic structure and create new strains. The type A viruses are further divided into serotypes, based on the antigenic nature of their surface glycoproteins hemagglutinin (H) and neuraminidase (N). Swine influenza in large herds may become endemic with intermittent bouts of disease and infertility. Different influenza strains may sequentially infect the herd. Immunity to influenza viruses is often short-lived (6 months). Outbreaks are seen throughout the year. Piglets generally are protected by maternal antibodies they receive in colostrum. Sows may show pregnancy loss secondary to fever and coughing. Weaner and grower pigs with acute illness classically are fine one day and then lying prostrate and breathing heavily the next.

Escherichia coli

Diarrhea is the most common and important disease of piglets. In a well-managed herd, there should be fewer than 3% of litters at any time requiring treatment for diarrhea and piglet mortality from diarrhea should be less than 0.5%. At birth, the gastrointestinal tract is microbiologically sterile. Organisms begin to colonize the tract quickly after birth, among them potentially pathogenic strains of E. coli. Ingestion of colostrum and later, of milk containing IgA, is vital for creation of immunity within the intestinal tract. If too many bacteria are present or if there are stressors present such as chilling or concurrent infection, piglets will succumb to disease. Periods of greatest risk are before 5 days of age and between 7 and 14 days of age. Weaning is another risk, as loss of sow’s milk and the IgA it contains allows the bacteria to attach to the villi of the small intestines. Signs may include acute death, dehydration, and sticky feces around the rectum and tail with an accompanying characteristic sour smell.

Rotavirus

This virus is widespread in pig populations, with virtually 100% seroconversion in adult stock. It is resistant to environmental changes and many disinfectants and so persists for long periods of time in the environment. Piglets are initially protected from maternal antibodies in colostrum but become susceptible to infection by about 3-6 weeks of age. Exposure does not necessarily result in disease; it is estimated that only 10-15% of diarrheas in pigs are due to primary rotavirus infection. The virus destroys the intestinal villi, preventing fluid uptake and causing watery diarrhea.

Porcine Proliferative Enteritis (PPE)

This is a disease characterized histologically by inflammation, ulceration, and hemorrhage in the intestinal tract. The causative organism, Lawsonia intracellularis, is a unique obligate intracellular organism related to anaerobic bacteria. Clinical disease is characterized as an acute form common in young adults and a chronic or necrotic form in grower pigs. Carrier animals shed the organism in their feces and susceptible pigs are exposed through the fecal-oral route. Carrier sows may infect nursing pigs as early as 6 days of age. Pigs present with pallor, weakness, and rapid death. Subacute to chronic cases occur more frequently in grower pigs, which show sporadic diarrhea, wasting, and variation in growth rate.

Porcine Circovirus Type 2 (PCV2)

This is a widespread virus and essentially all pig herds are infected. However, very few have PCV2-associated disease which can include a variety of systemic disorders including clinical signs of wasting, pneumonia, enteritis, and reproductive failure. The hallmark of PCV2 infection is depletion or inflammation of lymphoid tissue. In many cases, PCV2 infection requires a trigger such as concurrent infection (PRRS virus, Mycoplasma hyopneumoniae) or other stressors.

Meningitis

Hemophilus parasuis and Streptococcus suis are two organisms associated with inflammation of the meninges in pigs. Signs of meningitis in piglets and weaned pigs include rapid onset of recumbency, shivering, nystagmus (shaking of the eyeballs), paddling, and convulsions. In older pigs (growers and adults), muscle trembling, nystagmus, and incoordination are more common clinical signs.

Vaccines for Disease in Swine

Vaccination for Reproductive Disease

Common vaccinations include:

• Leptospirosis-Erysipelas-Parvovirus combination vaccine
  • Each of these components may be administered as individual vaccinations as well
• Porcine Reproductive and Respiratory Syndrome virus (PRRS) vaccine
  • Modified live virus vaccine typically thought to be most effective

Common uses are:

• Typically administered twice prior to the first breeding of gilts and once before subsequent gestation periods in reproductive herd (sows and boars)

Vaccination for Respiratory Disease

Common vaccinations include:

• Mycoplasma hyopneumoniae vaccine
  • Single dose and two dose versions exist
• Swine Influenza virus vaccine
  • Normally include H1N1 and H3N2 components
• Porcine Reproductive and Respiratory Syndrome virus (PRRS) vaccine

Common uses are:

• Routine vaccinations in reproductive herds to maintain respiratory disease stability
• Acclimation of disease-negative replacement females as they enter disease-positive herds
• Growing pigs at weaning or during the nursery phase to prevent significant respiratory disease during the finisher phase

Vaccination for Gastrointestinal Disease

Common vaccinations include:

• Escherichia coli vaccine
  • Multiple strains typically included in the vaccine
• Rotavirus vaccine
  • Modified live virus, only one type included in commercial vaccine
• Lawsonia intracellularis vaccine
  • A modified live vaccine that requires storage at -70°C and it administered orally following thawing and dilution

Common uses are:

• Escherichia coli and Rotavirus vaccines commonly used prior to farrowing to prevent neonatal scours in suckling piglets
• Lawsonia intracellularis vaccines administered in late nursery or early finisher (9-12 weeks of age) to prevent ileitis in finisher pigs OR for the acclimation of replacement females into breeding herds

Vaccination for Multi-Systemic Disease

Common vaccinations include:

• Porcine Circovirus Type 2 (PCV2) vaccine
  • Currently the most common vaccine used in swine
  • Considered to be highly effective in preventing a devastating disease syndrome
  • Evidence that it provides effective protection in both single and two dose programs.
• Hemophilus parasuis vaccine
  • Typically includes multiple serotypes that provide cross protection for other serotypes
• Erysipelas rhusiopathiae vaccine
  • May be delivered IM or PO
• Streptococcus suis vaccine
  • Efficacy is questionable
  • Commonly produced as an autogenous vaccine

Common uses are:

• These vaccines are often manufactured in combination type products with respiratory specific vaccines to prevent disease in replacement females or growing pigs.