Urinary tract infections: A silent but serious problem for sows and their progeny

In Brief

  • Improving the health of the sow during gestation can significantly boost the success of the progeny
  • Urinary tract infections (UTIs) in sows can reduce feed intake which lowers the quality and quantity of colostrum for piglets
  • Preventing UTIs can be achieved by implementing good management practices and providing a nutritionally balanced diet
  • Acidification of sow feed can help reduce the severity and the incidence of UTIs

Medication is commonly used in swine production to maintain the health status of animals and ensure optimal production performance targets are met. But with increasingly strict restrictions on the use of medication being implemented, alternative strategies must be adopted.

It is widely accepted that the best performing animals are those that get a good start in life. But the thinking now includes one step earlier in the lifecycle: the sow, and her health during gestation and farrowing. This article investigates the impact of urinary tract infections (UTIs) in the sow during gestation, and how preventing them can promote piglet health and performance.

Stricter restrictions

Worldwide restrictions on medication use in swine production to help combat the rise of antimicrobial resistance has been a constantly evolving situation over the last two decades with tighter restrictions being implemented over time. Given the limited tools currently available in the market to safeguard piglets during their early weeks of life, it is crucial to explore alternative strategies beyond medications including therapeutic zinc oxide (ZnO). Other factors that could potentially impact piglet robustness, quality, and overall performance must be considered.

In recent years, there has been increasing interest on maternal influence, and research has demonstrated that the health of the sow during gestation, particularly around farrowing, colostrum offset and lactation, can significantly impact the success of her progeny.

Infection of the microbiome

The sow’s microbiome can act as a reservoir of infection which may lead to antimicrobial resistance transfer to her progeny. It is estimated that sows will be treated with at least one antimicrobial ingredient for an average of 3.2 days/year (Hemme et al., 2018). One of the primary reasons for antimicrobial usage is in the treatment of UTIs. Urinary tract infections can significantly impact the health and productivity of sows. Unfortunately, UTIs are often difficult to detect as they may not display any visible symptoms. Specific tests are required for diagnosis which means cases are frequently overlooked or underestimated.

UTIs in sows

Urinary tract infections are more common in older sows compared to younger ones, with the farrowing unit being particularly affected. During the transition period, significant physiological changes occur, weakening the sow's immune system and reducing protection against pathogens. Among the physiological changes are weakness of the vaginal muscle, and concentration of the urine to retain water leading to less urination. In addition, sows in farrowing crates have limited space for movement, increasing their risk of exposure to fecal matter and bacteria, raising the incidence of UTIs.

Signs of UTIs

Signs that sows are suffering with a UTI may include:

  • Insufficient milk production
  • Postpartum dysgalactia syndrome (PDS)
  • High fever
  • Yellowish discharge from the uterus
  • Weight loss
  • Sickness
  • Death in severe cases

Urinary tract infections can cause discomfort and pain in sows, resulting in reduced feed intake, weight loss and poorer milk production, leading to reduced colostrum quantity and quality for piglets.

Piglets rely on sow milk for nutrition and disease protection during the early stages of life. Reduced milk production and poor colostrum quality will negatively impact piglet health and robustness. Producers must implement measures to prevent and treat UTIs in sows as part of an overall strategy to promote the health and welfare of both sows and piglets.

Causes of UTIs in sows

Urinary tract infections in sows can arise due to various factors, including:

  • Inadequate feed intake
  • Inadequate water intake
  • Insufficient flushing of the urinary tract
  • Poor hygiene practices

The pH level of the urinary tract can also be influenced by feed ingredients, leading to increased susceptibility to bacterial growth. Common agents responsible for UTIs in sows include Escherichia coli, Actinobaculum suis, Streptococcus spp. and Staphylococcus spp.

Preventing UTIs

Prevention is essential for reducing the risk of UTIs in sows and some important factors to pay close attention to include:

  • Providing clean and sufficient feed and water
  • Providing sows with a balanced diet that meets their nutritional requirements
  • Acidification of feed
  • Ensuring proper flushing of the urinary tract
  • Maintaining good hygiene during birth assistance
  • Keeping the area behind the sow clean to reduce the risk of bacterial growth
  • Maintaining the appropriate temperature in the barn
  • Maintaining the appropriate humidity level in the barn
  • Acidification of feed can support in preventing UTIs, and benzoic acid has been shown to be an efficient acidification tool. Ultra-pure benzoic acid (VevoVitall®) with a pKa of 4.19, is not oxidized by pigs after ingestion and is largely absorbed in the gut. Upon conversion in the liver through a reaction with glycine, the resulting hippuric acid (pKa 3.8) is excreted by the kidneys and acts as a natural acidifier in the urine (Figure 1). This pH reduction is useful in reducing the incidence and severity of UTIs in sows by preventing bacterial growth and crystalluria, which are both risk factors for UTIs.

Figure 1. How benzoic acid acts as a natural acidifier in the urine (Source: dsm-firmenich, 2023)

Lowering urinary pH using benzoic acid can contribute to supporting sow health and welfare by reducing the risk of urinary tract disorders in sow herds, reducing the need for antimicrobial treatment and reducing pathogen exposure to progeny.


Urinary tract infections in sows can have a significant impact on piglet health and growth. Swine producers should take appropriate measures to prevent and treat UTIs as part of a wider strategy to promote the health and welfare of both sows and piglets.

Urinary tract infections can cause discomfort and pain in sows, resulting in reduced feed intake and weight loss, leading to poorer colostrum and milk production and quality for piglets.

Urinary tract infections in sows arise due to various factors, including inadequate feed and water intake, insufficient flushing of the urinary tract and poor hygiene practices. Prevention methods include providing clean and sufficient water and feed, ensuring proper flushing of the urinary tract and maintaining good hygiene during birth assistance.

Proper nutrition is crucial for preventing UTIs in lactating sows and acidification of feed can be effective in preventing UTIs. Additionally, benzoic acid is an efficient agent for acidifying urine which can have the effect of reducing the incidence and severity of UTIs in sows, improving the health status of the sow and consequently boosting piglet health and performance.


Hemme, M., Ruddat, I., Hartmann, M., Werner, N., van Rennings, L., Käsbohrer, A. and Kreienbrock, L. (2018). Antibiotic use on German pig farms - A longitudinal analysis for 2011, 2013 and 2014. PLoS One. 2018;13(7):e0199592. https://doi.org/10.1371/journal.pone.0199592

Published on

30 May 2023


  • Swine
  • Sows
  • Acidifiers

About the Author

Mariana Masiero - Global Swine Marketing Manager, Animal Nutrition and Health at dsm-firmenich

Mariana Masiero is Global Swine Marketing Manager at dsm-firmenich. Mariana, a Brazilian national, holds a degree from the University of São Paulo, BR, and a PhD in Animal Science focused on animal nutrition from the University of Missouri, USA. She joined Biomin®, now part of dsm-firmenich, in 2019 as a Global Product Manager for phytogenics. 


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