Metritis is an inflammation of the uterus (uterine cavity and entire uterine wall), and is generally caused by bacterial infection.
The risk factors for uterine infection include retention of the placenta, poor hygiene in the calving environment, twins, difficult calving and a poor transition diet. Retained placenta is a particularly important predisposing factor for uterine infection.¹
Metritis is characterised by an abnormally enlarged uterus, a foetid watery red-brown or purulent uterine discharge and may be associated with signs of systemic illness (decreased milk yield, dullness or other signs of toxaemia) and fever >39.5ᵒC. It occurs within 21 days after calving, but is most commonly seen in the first 10 days after calving.²
Metritis can vary in severity. Typically we grade metritis from 1 to 3, with 1 being mild and 3 being severe.²
The detection of purulent discharge uterine discharge >21 days after calving is classified as clinical endometritis. The deeper layers of the uterus are not affected by endometritis.
Metritis is a much more severe disease than endometritis and requires a different approach to treatment.
Metritis makes the cow more susceptible to ketosis, displaced abomasum and other postpartum ailments and can lead to impaired fertility – either temporary or permanent – and even, on occasions, to death.
The uterus of cows shortly after calving is usually contaminated with a range of bacteria which originate from the surface of the animal and the environment, but this is not consistently associated with clinical disease². The development of uterine disease depends on the immune response of the cow, as well as the species and number (load or challenge) of bacteria.
Elimination of this contamination will depend on uterine involution, regeneration of the endometrium, and uterine defence mechanisms.
Typically, 25–40% of animals develop clinical metritis in the first 2 weeks after calving, and disease persists in up to 20% of animals as clinical endometritis.¹ The bacteria commonly associated with uterine disease are Escherichia coli, Arcanobacterium pyogenes, Fusobacterium necrophorum and Prevotella species¹.
Some uterine discharge for about two weeks after calving is a normal sign of healthy involution and evacuation of the uterus. But when a foul-smell and fever accompany this watery vaginal discharge, metritis is usually the cause.
In addition to the discharge, symptoms include fever, decreased appetite, dehydration, depression and reduced milk production.
The use of clinical records of stillbirth, twins, retained foetal membranes, dystocia and hypocalcemia helps identify animals at risk of uterine disease, but does not provide a specific diagnosis².
The usual method of diagnosis of uterine disease is to withdraw the mucus contents of the vagina manually for examination, using a clean lubricated gloved hand after wiping the vulva using a clean paper towel. Other options are to use vaginoscopy, using autoclavable plastic or disposable foil-lined cardboard vaginoscopes, to visualise the mucus flowing out of the cervix, or to use an instrument to withdraw the vaginal contents¹.
Prompt treatment with a systemic broad-spectrum antibiotic that penetrates into the infected uterus and is active against the metritis causing bacteria as well.
Supportive treatments: rehydration therapy, NSAIDs, propylene glycol, etc.
Little progress has been made toward the control or prevention of retained placenta or uterine disease, however, based on the current understanding of these diseases, the general objective is to support and maintain the cow’s natural immunity to reduce the risk that the inevitable inflammation and bacterial contamination after calving progress to metritis³.
Use these management practices to decrease the incidence of metritis:
Appropriate transition cow management
Clean, dry calving facilities
Sanitary calving assistance
Metritis can have a profound effect on cow performance and profitability, given that the disease can cause1:
Prolonged days open, due to lower conception and oestrus detection rates
Higher insemination costs, due to repeat artificial insemination services
Increased culling rate, resulting in higher replacement costs
Greater costs for veterinary interventions
1. I. Martin Sheldon, Erin J. Williams, Aleisha N.A. Miller, Deborah M. Nash, Shan Herath. Uterine diseases in cattle after parturition. The Veterinary Journal 176, 115–121.
2. I. Martin Sheldon,, Gregory S. Lewis, Stephen LeBlanc, Robert O. Gilbert (2006) Defining postpartum uterine disease in cattle. Theriogenology 65, 1516–1530.
3. Stephen Leblanc (2012), Integrating metabolic and reproductive health in dairy cows. Keynote Lecture- XXVII World Buiatrics Congress, Lisbon.