Swine respiratory disease (SRD) poses a persistent threat to pork producers globally, as it is both difficult to properly treat and economically debilitating. When it comes to combating SRD, producers are not alone in determining what treatment from the SRD toolbox makes the most sense for their operation. SRD impacts swine operations differently, so producers should work closely with their veterinarian to understand the unique pathogen, host, and environmental challenges they are facing to develop a comprehensive treatment plan.
Identifying the Pathogens Causing SRD in your Herd
Understanding which pathogens are causing SRD in your herd is key to developing an effective treatment plan. Through routine diagnostic monitoring, pathogens can be detected quickly allowing for time to delay animal movements and deploy the appropriate treatment. Moreover, it can allow disease patterns to be tracked over an extended period of time. Each swine operation faces unique challenges, so developing an understanding of where your herd is at an increased risk of infection from a specific pathogen can play into future treatment planning and timing.
Primary pathogens include viruses and bacteria considered the definitive cause of disease in healthy swine. A common viral primary pathogen is porcine reproductive and respiratory syndrome virus (PRRSV). Common bacterial primary pathogens include Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae. 1
Secondary pathogens include disease agents, which normally don’t cause disease in healthy swine, to become more fatal when the immune system is weakened by concurrent infections. Common secondary pathogens, also known as opportunistic, include Pasteurella multocida, Glaesserella (Haemophilus) parasuis, and Streptococcus suis. 1
Routine diagnostic testing through polymerase chain reaction (PCR), serology, culture, and histopathology on respiratory samples such as nasal swabs, lung tissue, and oral fluids are imperative in determining the causative pathogens and identifying disease patterns.
Targeting Pathogens with the Right Treatment
As previously mentioned, each swine operation experiences unique pathogen, host, and environmental challenges. With routine diagnostics, the health history of a specific flow of pigs can be understood. However, even when the pathogen and host are known, a different barn or site may have differing water quality, ventilation systems or proximity to other pigs, to name a few. For that reason, there is no one-size-fits-all approach to managing SRD.
Any viral infections that cause SRD are best managed through vaccination prior to infection. Through vaccination, producers can greatly mitigate the risk associated with viral pathogens causing SRD and protect an operation’s economic viability.
Treating bacterial infections commonly associated with SRD requires a greater in-depth understanding of the pathogen. All bacteria have different traits requiring treatments with the correct mode of action in order to be effective. For example, a key difference is whether a bacterial cell has a thin cell wall and outer membrane (gram-negative) or a comparatively thicker wall (gram-positive) making treatment more difficult. 1 In addition to the cell wall, ribosomes, which assist in making the proteins for cell growth, and the nucleoid, which is responsible for reproduction, can be targeted. By identifying the specific bacterium, the most effective treatment with the proper mode of action can be administered, helping to prevent the spread of infection.
Customized SRD Toolbox
The SRD toolbox includes vaccines, anti-inflammatories and antibiotics. There are products in each category with different modes of action that are important for each pathogen. It is also important to consider if injectable, water soluble or feed grade is the best route of administration. The severity of clinical symptoms and how quickly clinical signs develop will play a role in deciding the treatment process. For instance, if a pig needs to be treated today, it needs to be injected. Water soluble medications are for the pigs that can wait until tomorrow, and feed medications are an option for pigs that can wait until next week. This is the time it takes for medicine to be delivered to the farm, get into the water or feed system, and consumed by the pig in a high enough quantity to have an impact on the tissues where the infection is – IF the pig is feeling well enough to get up to eat and drink. In reality, subpopulations of pigs are likely at different phases of the disease, so a tiered approach is often used when treating SRD.
Elanco offers the most comprehensive SRD toolbox available for producers. This includes tools to mitigate production loss when administered ideally prior to PRRS challenges such as Prevacent®. Elanco also has solutions like Pulmotil® AC (tilmicosin phosphate) and Pradalex® (pradofloxacin injection) for bacteria commonly associated with PRRSV like Streptococcus suis, Glasserella parasuis, Pasteurella multocida, and Mycoplasma hyopneumoniae. Pradelex® is a low-volume injectable antibiotic with a 2-day withdrawal period that allows for treatment flexibility from the nursery to the finish stage. It works by interrupting bacterial cell reproduction at the nucleoid level, inhibiting enzymes key for DNA replication and chromosome separation during cell division.
SRD’s impact on swine operations is difficult to manage and directly impacts the economic viability of swine operations globally. However, by working closely with your veterinarian to develop the proper treatment plan for your herd, SRD can be prevented and controlled. Elanco’s SRD toolbox covers all routes of administration necessary for each operation’s unique situation, whether it requires injectable, water soluble or feed grade solutions.
The labels contain complete use information, including cautions and warnings. Always read, follow and understand the label and use directions.
Pulmotil® AC (tilmicosin phosphate)
IMPORTANT SAFETY INFORMATION:
Before using this product, it is important to read the entire product insert, including the boxed human warning.
WARNING: Exposure to tilmicosin in humans has been associated with chest pain, increased heart rate, dizziness, headache, and nausea. Death has been reported following ingestion or injection of tilmicosin. Avoid direct skin and eye contact. In case of human exposure, call 1-800-722-0987 and consult a physician immediately.
- Wear overalls, impervious gloves and eye protection when mixing and handling the product. Wash hands after handling the product. Wash affected parts if skin contact occurs. If accidental eye contact occurs, immediately rinse thoroughly with water.
INDICATIONS:
- For the control of swine respiratory disease associated with Pasteurella multocida and Haemophilus parasuis in groups of swine in buildings where a respiratory disease outbreak is diagnosed.
- For the control of swine respiratory disease associated with Mycoplasma hyopneumoniae in the presence of porcine reproductive and respiratory syndrome virus (PRRSv) in groups of swine in buildings where a respiratory disease outbreak is diagnosed.
DOSAGE AND ADMINISTRATION:
- Must be diluted before administration to animals.
- Include in the drinking water to provide a concentration of 200 mg tilmicosin per liter (200 ppm).
- One 960 mL bottle is sufficient to medicate 1200 liters (320 gallons) of drinking water for pigs.
- The medicated water should be administered for (5) five consecutive days.
- Use within 24 hours of mixing with water.
- Do not use rusty containers for medicated water as they may affect product integrity.
- When using a water medicating pump with a 1:128 inclusion rate, add 1 bottle (960 mL) of Pulmotil AC per 2.5 gallons of stock solution.
CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian.
- For use only in swine. Not for injection. Injection of tilmicosin has been shown to be fatal in swine and non-human primates, and may be fatal in horses and goats.
- Swine intended for human consumption must not be slaughtered within 7 days of treatment.
- Always treat the fewest number of animals necessary to control a respiratory disease outbreak. Prescriptions shall not be refilled.
- Concurrent use of Pulmotil AC and another macrolide by any route, or use of another macrolide immediately following this use of Pulmotil AC is not advised.
- Ensure that pigs have continuous access to medicated water during the treatment period. Monitor pigs for signs of water refusal and dehydration while being treated.
The Pulmotil® AC (tilmicosin phosphate) label can be found here.
Pradalex® (pradofloxacin injection)
INDICATIONS:
- Pradalex is indicated for the treatment of SRD associated with Bordetella bronchiseptica, Glaesserella (Haemophilus) parasuis, Pasteurella multocida, Streptococcus suis and Mycoplasma hyopneumoniae in weaned swine intended for slaughter (nursery, growing, and finishing swine, boars intended for slaughter, barrows, gilts intended for slaughter, and sows intended for slaughter). Not for use in swine intended for breeding (boars intended for breeding, replacement gilts and sows intended for breeding) and in nursing piglets.
DOSAGE AND ADMINISTRATION:
- Swine: Administer once as an intramuscular injection in the neck at a dosage of 7.5 mg/kg (1.7 mL/100 lb) body weight. Do not inject more than 5 mL per intramuscular injection site.
IMPORTANT SAFETY INFORMATION:
- CAUTION: Federal law restricts this drug to use by or on the order of a licensed veterinarian. Not for use in humans. Keep out of reach of children. Avoid contact with eyes and skin. Individuals with a history of hypersensitivity to quinolones should avoid this product. Not for use in animals intended for breeding because the effects of Pradalex on swine reproductive performance, pregnancy and lactation have not been determined. Not for use in nursing piglets because safety and effectiveness have not been demonstrated. Quinolones should be used with caution in animals with known or suspected central nervous system (CNS) disorders. Mild to moderate inflammatory changes of the injection site may be seen in swine treated with Pradalex. See package insert for additional safety information.
The Pradalex® (pradofloxacin injection) label can be found here.
Prevacent®
INDICATIONS:
- This product has been shown to be effective for the vaccination of healthy pigs 2 weeks of age or older against PRRS respiratory disease; and against reproductive disease when vaccinated 6 weeks prior to breeding.
- The duration of immunity against respiratory disease is at least 26 weeks.
- The duration of immunity against reproductive disease has not been established. For more information regarding efficacy and safety data, go to productdata.aphis.usda.gov.
- Safety of this product has been demonstrated when sows or gilts are vaccinated prior to breeding or at any stage of pregnancy.
- Vaccine virus may be shed and transmitted to other populations of swine in contact with vaccinated swine.
- The duration of potential vaccine virus transmission may vary.
- Use of the vaccine in herds intended to remain PRRS virus seronegative is contraindicated.
- Introduction of vaccinated pigs into herds intended to remain PRRS virus seronegative is contraindicated.
DOSAGE AND ADMINISTRATION:
- Rehydrate with the accompanying sterile diluent.
- Shake well and draw back into the syringe the required amount.
- Administer 1 mL intramuscularly.
- The need for annual booster vaccinations has not been established for this product; consultation with a veterinarian is recommended.
IMPORTANT SAFETY INFORMATION
PRECAUTIONS:
- Store at 2°- 8°C (35°- 46°F). DO NOT FREEZE.
- Use entire contents when first opened.
- Do not mix with other products, except as specified on this label. In case of human exposure, contact a physician.
- Do not vaccinate within 21 days before slaughter.
- Inactivate unused contents before disposal.
- Anaphylactic reactions may occur. Symptomatic treatment: Epinephrine. Contains gentamicin as preservative.
The Prevacent® label can be found here.
Sources
1 Brockmeier, S., Halbur, P., et al. “Porcine Respiratory Disease Complex.” In: “Polymicrobial Diseases.” ASM Press. https://www.ncbi.nlm.nih.gov/books/NBK2481/
Pradalex, Prevacent, Pulmotil, Elanco, and the diagonal bar logo are trademarks of Elanco or its affiliates.
© 2025 Elanco or its affiliates.
PM-US-25-2292
