Postpartum dysgalactia syndrome (PDS) is a multifactorial syndrome characterized by inadequate production of milk and colostrum. Historically referred to as mastitis, metritis, and agalactia (MMA), PDS is a more encompassing definition because evidence of mastitis, metritis, or agalactia is not present in all cases. Clinical signs in sows are nonspecific and can vary but may include elevated rectal temperature, inflammation of one or several mammary glands, anorexia, and hypogalactia. Other indicators include increased piglet mortality or piglets that fail to thrive or gain weight. No definitive diagnostic tests exist because of the multifactorial nature of the syndrome. Treatment includes NSAIDs, as well as oxytocin to stimulate milk letdown. Antimicrobials might be indicated if an underlying infection (ie, mastitis or metritis) is suspected.
Postpartum dysgalactia syndrome (PDS) is defined by insufficient colostrum and milk production during the first few days after farrowing. PDS has been characterized by a combination of one or more of the following clinical signs in sows:
rectal temperature > 39.5°C (103.1°F) within the first few days post partum
inflammation of one or several mammary glands (eg, redness, edema, palpable hardening, skin congestion)
decreased appetite or anorexia
Poor piglet behavior (eg, crushing or overlying of piglets) and diarrhea, unthriftiness, slow growth, and increased mortality among piglets are usually the most common indicators that a sow is affected by PDS.
Etiology of Postpartum Dysgalactia Syndrome in Sows
Postpartum dysgalactia syndrome is a multifactorial syndrome without an exact etiological diagnosis. It has been hypothesized to occur from an unsuccessful transition from pregnancy to lactation, with three potential risk factors that could impair this transition: endotoxemia, stress, and overweight sows not eating after farrowing (1).
Endotoxemia can come from many different sources during the postpartum period, such as mastitis, metritis, or any underlying infection. Milk samples obtained from sows affected by PDS have been found to be contaminated by Staphylococcus spp, Streptococcus spp, and mostly coliforms, thereby suggesting a potential fecal route of transmission. However, it is important to note that this composition of bacteria is similar to that in milk samples from healthy sows.
Affected sows show increased cortisol concentrations, as well as inflammatory and metabolic biomarkers. Multiple studies show increased concentrations of tumor necrosis factor (TNF)-alpha, IL-6, haptoglobin, and C-reactive protein associated with PDS (2, 3). Additionally, affected sows have shown decreased lymphocyte and neutrophil counts, which can be explained by the migration of these cells to the mammary gland. Although the abnormal biomarkers can be suggestive for PDS, these changes alone are not diagnostic; there are other potential causes. Sows that are overweight tend to have a longer farrowing duration and more farrowing complications, which can lead to postfarrowing anorexia and further risk of catabolism. This, combined with the modern, hyperprolific females, can lead to an increased incidence of PDS as well, particularly in early parity females.
Clinical Findings of Postpartum Dysgalactia Syndrome in Sows
Clinical signs in sows affected with postpartum dysgalactia syndrome are highly variable and not always apparent. In many cases, the impact on the litter is the first clinical indication that there is a problem with PDS. Most cases occur during the first 3 days post partum but can occur anytime during the first week.
Mastitis can occur in all the mammary glands or be localized to a single gland. There does not appear to be a predilection for specific mammary complexes or locations. Affected sows can seem restless. They might refuse to lie down or choose to lie on their sternum instead of their side, preventing piglets from accessing the udder. They might have an elevated rectal temperature above 39.5°C (103.1°F). A history of anorexia might also be present in sows with PDS.
The impact of PDS on piglets is readily apparent, affecting their behavior and well-being. Milk ejection in affected sows is either absent or of brief duration, which causes the piglets to actively nurse for an extended time (> 5 minutes every 40–50 minutes). During the initial stages, piglets repeatedly attempt to nurse at frequent intervals, appearing to be more restless and aggressive and not settling after nursing. Unthrifty piglets, showing clinical signs of diarrhea, poor weight gain, and increased mortality rate, are also associated with PDS.
Diagnosis of Postpartum Dysgalactia Syndrome in Sows
Clinical examination of sow and piglets
Careful exclusion of other differential diagnoses
Diagnosis of postpartum dysgalactia syndrome is difficult and based on clinical signs.
Affected sows might have an elevated body temperature. An arbitrary value of > 39.5°C (103.1°F) in the period immediately post partum has been proposed to classify sows as having fever. The problem with using this cutoff is that normal postpartum sows can also have rectal temperatures above this range. Healthy sows also have increased rectal temperatures in the periparturient period, and rectal temperatures can vary considerably between sows and within sows over time.
A diagnosis of PDS must take into account the sow’s clinical presentation as well as piglets' clinical presentation. Mammary tenderness, swelling, and teat damage can be consistent with a diagnosis of lactational deficiency. Clinical signs in piglets such as diarrhea, unthriftiness, decreased growth, and higher mortality rate are often a more reliable diagnostic indicator of PDS. Postmortem examination is rarely performed.
Blood biomarkers (ie, TNF-alpha, cytokines, interleukins) have been studied as aids in the diagnosis of PDS (2). However, establishing a threshold value has proved challenging because of the large amount of pig-to-pig variation and the impact of parity and reproductive states.
Because of the uncharacteristic clinical presentation of PDS, numerous pathologies can be considered as part of the differential diagnosis. Porcine reproductive and respiratory syndrome (PRRS) virus, influenza A virus, retained pigs, metritis, cystitis, and other causes of pyrexia and lethargy in sows should be considered.
Treatment, Control, and Prevention of Postpartum Dysgalactia Syndrome in Sows
Antimicrobials and anti-inflammatories
Oxytocin
For treatment of postpartum dysgalactia syndrome, most treatment protocols indicate the administration of anti-inflammatories (eg, NSAIDs) to help with pyrexia, inflammation, and endotoxemia. The most common NSAID used in commercial farms is flunixin meglumine (2.2 mg/kg, IM, once) (4). Other anti-inflammatories have been mentioned (meloxicam, dexamethasone, ketoprofen) but require a veterinary prescription following the Animal Medicinal Drug Use Clarification Act (AMDUCA) guidelines.
Antimicrobials might be warranted if an underlying infection is suspected (eg, mastitis or metritis). Antimicrobial treatment is usually started before susceptibility testing; therefore, a broad-spectrum antimicrobial is recommended. Because sows are often culled at weaning, withdrawal times are important to consider before prescribing antimicrobial or anti-inflammatory treatment. Moreover, if antimicrobials are used long-term, a dependence on them for postpartum fevers, acute mastitis, metritis, or neonatal diarrhea can develop, leading to the potential for multiresistant bacterial infections.
Pearls & Pitfalls
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Oxytocin given parentally is generally effective in reestablishing lactation if administered 4 or 5 times at 2- to 3-hour intervals, or until lactation is reestablished. Care must be taken not to overuse parental oxytocin, because the inhibition of endogenously produced oxytocin can cause poor litter performance.
Cross-fostering the piglets from affected to healthy sows, as long as the health status of the litters is equivalent, is another effective strategy in management of PDS.
Moving sows to farrowing rooms < 4 days before the expected farrowing date, inducing farrowing, leaving sows unsupervised during farrowing, and feeding sows ad libitum both before farrowing and during the first few days of lactation might increase the risk of PDS.
At the individual sow level, younger sows (lower parity), sows with a high number of piglets born alive, sows with an increased number of stillbirths, farrowings with dystocia, and sows with a previous history of PDS or increased assistance during parturition are at an increased risk for PDS. Therefore, sows should be monitored during farrowing, but active interventions should be limited to cases of strict necessity in which the survival of the piglet is compromised.
Seasonality and induction of farrowing seem to have an inconsistent effect on risk for PDS. However, sows that are cleaner at farrowing seem to have a lower prevalence of mastitis. Washing the sows, disinfecting the farrowing rooms, and housing the sows on slatted floors can decrease the risk of mastitis.
Key Points
Postpartum dysgalactia syndrome is a multifactorial and underestimated condition of swine herds.
Diagnosis of PDS is challenging and is based on clinical signs of the sow and its litter.
Good swine management practices are essential to decrease the occurrence of PDS.
For More Information
Maes D, Farmer C. Postpartum dysgalactia syndrome in sows: a review. In: Gross JJ, ed. Production Diseases in Farm Animals. Springer; 2024:319-338.
References
Martineau GP, Le Treut Y, Guillou D, Waret-Szkuta A. Postpartum dysgalactia syndrome: a simple change in homeorhesis?J Swine Health Prod. 2013;21(2):85-93. doi:10.54846/jshap/731
Kaiser M, Jacobson M, Andersen PH, et al. Inflammatory markers before and after farrowing in healthy sows and in sows affected with postpartum dysgalactia syndrome. BMC Vet Res. 2018;14(1):83. doi:10.1186/s12917-018-1382-7
Kaiser M, Jacobsen S, Andersen PH, et al. Hormonal and metabolic indicators before and after farrowing in sows affected with postpartum dysgalactia syndrome. BMC Vet Res. 2018;14(1):334. doi:10.1186/s12917-018-1649-z
Hirsch AC, Philipp H, Kleemann R. Investigation on the efficacy of meloxicam in sows with mastitis–metritis–agalactia syndrome. J Vet Pharmacol Ther. 2003;26(5):355-360. doi:10.1046/j.1365-2885.2003.00524.x
