Understanding Metritis and Its Impact on Your Dairy Farm


What is Metritis & Its Effects?

Metritis is the inflammation of the uterus caused by infection with bacteria post-calving. Approximately 20-40% of dairy cows in a herd experience some degree of metritis¹.

Metritis is one of the biggest issues dairy farmers are facing as it negatively impacts the cow’s well-being, milk production, reproductive performance, and farm profitability.

A recent study estimated that the average cost of a metritis case is $512 on American dairy farms². Cows, who had metritis, produced about 814 kg less milk per lactation (in 305 DIM) than healthy cows². With the milk at an estimated price of $0.395/kg, there was an estimated $322 loss in milk sales per cow². Metritis treatment, being $118/cow on average, can also be costly².

Metritis often results in impaired reproductive performance, which unfortunately is the leading reason for the culling of dairy cows in Canada. As much as dairy farmers care for their cows, they cannot afford to keep them if they cannot produce milk. These cows can still provide for families through the production of beef products. In 2019, the rate for culling dairy cows due to reproductive reasons was 15.9% in Canada³. Reproductive issues that arise are delayed estrous cycle, increased number of days open, poor reproductive performance, and an increased calving-to conception-interval². All this leads to added costs, lost revenues, but most importantly, poor cow health and poor cow well-being.

What are the Risk Factors?

Risk factors increase the chances that harmful bacteria will enter the uterus, which will negatively affect their microbiome composition and result in a uterine infection.

Some risk factors are primiparous cows, unsanitary cows or environment, decreased feed intake, and complex calving situations such as a retained placenta, obstructed labour (dystocia), twins, stillbirths, etc⁴. Cows with these risk factors should be closely monitored.

What are the Signs?

There are different types of post-calving uterine infections classified by the time at which they occur and their signs⁵.

Uterine Infection

Days after Calving


Puerperal Metritis

Within 21 days after calving, most commonly within 10 days after calving

  • Enlarged uterus
  • Fetid, watery, reddish-brown discharge
  • Systemic signs of illness (decreased appetite, decreased milk production, dehydration, fever > 39.5°C or 103.1°F)

Clinical Metritis

Within 21 days after calving

  • Enlarged uterus
  • Fetid, watery, reddish-brownish, purulent (pus) or mucopurulent (mucus and pus) discharge
  • No systemic signs of illness

Clinical Endometritis

21+ days after calving

  • Purulent or mucopurulent discharge
  • No systemic signs of illness

Subclinical Endometritis

21+ days after calving

  • No clinical signs
  • Elevated number of neutrophils in cytology samples



  • Enlarged uterus
  • Accumulation of pus in the uterus
  • Corpus luteum present
  • Cervix often closed

Metritis & The Microbiome

After calving, the uterus is open and needs to return back to normal size through involution. Bacteria from the environment take advantage of this and enter the uterus to disrupt the reproductive microbiome. The bacteria grows quickly, replicates itself, and damages uterine barriers, leading to metritis. The pathogenic bacteria most commonly associated with metritis are Escherichia coli, Trueperella pyogenes, Fusobacterium necrophorum and Prevotella melaninogenicus³.

The microbiome of the reproductive tract is home to a community of diverse bacteria. A study determined that the main groups of bacteria in the reproductive microbiome are Firmicutes (64%), Bacteroidetes (27.7%), Fusobacteria (2.9%), Proteobacteria (1.8%), Tenericutes (1.3%), and Actinobacteria (1.1%)⁶. However, the reproductive microbiome of cows that are healthy and those that develop metritis are significantly different. In cows that developed metritis, there was a disruption of the reproductive microbiome. They had a decreased amount of Proteobacteria and Tenericutes, and an increased amount of Bacteroidetes, Fusobacteria, and other bacteria³. There were also greater amounts of pathogenic E. coli. This dysbiosis contributes to the development of inflammation and reproductive infections that negatively affect milk production, cow health, and reproduction.

A healthy and diverse reproductive microbiome is needed to create a strong environment and immune system that readily defends against pathogens and infections. Metritis and other uterine infections are widespread issues that greatly contribute to decreased productivity and profitability of dairy farms. To reduce the burden of metritis, farmers should strive to be more proactive through early detection and prevention. 




  1. Sheldon IM, Williams EJ, Miller ANA, Nash DM, Herath S. Uterine diseases in cattle after parturition. Vet J. 2008. doi:10.1016/j.tvjl.2007.12.031
  2. Silva T V, Risco CA, Chebel RC, et al. The economic cost of metritis in dairy herds. J Dairy Sci. 2021. doi:10.3168/jds.2020-19125
  3. Rosales EB, Ametaj BN. Reproductive Tract Infections in Dairy Cows : Can Probiotics Curb Down the Incidence Rate ? 2020:1-32.
  4. Hossein-Zadeh NG, Ardalan M. Cow-specific risk factors for retained placenta, metritis and clinical mastitis in Holstein cows. Vet Res Commun. 2011. doi:10.1007/s11259-011-9479-5
  5. Sheldon IM, Lewis GS, LeBlanc S, Gilbert RO. Defining postpartum uterine disease in cattle. Theriogenology. 2006. doi:10.1016/j.theriogenology.2005.08.021
  6. Miranda-CasoLuengo R, Lu J, Williams EJ, et al. Delayed differentiation of vaginal and uterine microbiomes in dairy cows developing postpartum endometritis. PLoS One. 2019;14(1):1-23. doi:10.1371/journal.pone.0200974

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