If you go to five dairies, you may get five different definitions of metritis. Though farm teams know that metritis is an inflammation of the uterus, the clinical signs that each operation uses to make treatment decisions can widely vary.
In a broad sense, metritis involves abnormal vaginal discharge and, occasionally, also systemic symptoms such as fever or a drop in milk. But what is “abnormal” discharge, and are cows without systemic signs really that sick? Adrian Barragan, an associate research professor at Penn State, discussed those questions in an I-29 Moo University webinar.
Most people agree that abnormal discharge in the case of metritis has a red-brown color, watery viscosity, and a foul smell. Barragan highlighted a study their group did that evaluated cows with watery, red-brown discharge that either smelled or didn’t. What they found was that even without the hallmark foul smell of metritis, those cows with what looked like abnormal discharge had lower rumination and milk production just like the cows with smelly discharge. They also had higher habtoglobin levels, which is an indicator of inflammation.
“Those animals are diseased; they are sick,” he said of the cows that don’t exhibit the smell many farmers use to classify metritis.
If we have to make a definition of metritis, Barragan recommended identifying it when there is red-brown, watery discharge. There may or may not be a smell, and there may or may not be systemic signs.
Making diagnoses
Metritis has wide effects on cows. It causes pain, changes performance and behavior, and can have long-lasting reproductive implications. Barragan cited research where cows with metritis produced less milk (particularly multiparous cows), spent more time lying down (primiparous cows), were culled more often, had poorer reproductive performance, and arched their back more when rectally palpated — a signal of more inflammation and pain. “We know it definitely is affecting the welfare, and we have to do something about that,” he said.
How do we find these cases so that we can make a treatment decision? Uterine issues — metritis as well as retained placenta and pyometra — are some of the most common diseases seen on dairies, right alongside mastitis and lameness. Between direct and indirect costs, uterine disease can cost between $106 and $360 per case.
Visual observation is the least invasive method of diagnosis and effective use, Barragan encouraged. Walk your fresh pen one to two hours after feeding, when most cows should be lying down. The pressure of their organs on the reproductive system will force some of that uterine fluid out, and you can look for red-brown, watery discharge.
He noted that this method will likely not detect every case of metritis. For more thorough diagnostics, a metricheck is useful. This is a device that is put into the uterine cavity and captures a small measure of fluid to be evaluated.
Uterine ultrasound can also be used to identify uterine fluid and the thickness of the uterine wall. In cases where we already know there is a problem and need to gather more information, Barragan noted that a cytobrush or uterine lavage can be used to collect cells from the uterine lumen or wall for further analysis.
