Defining postpartum uterine disease in cattle.

Uterine function is often compromised in cattle by bacterial contamination of the uterine lumen after parturition, and pathogenic bacteria often persist, causing uterine disease, a key cause of infertility in cattle. However, the definition or characterization of uterine disease frequently lacks precision or varies among research groups. The aim of the present paper was to provide clear clinical definitions of uterine disease that researchers could adopt. Puerperal metritis should be defined as an animal with an abnormally enlarged uterus and a fetid watery red-brown uterine discharge, associated with signs of systemic illness (decreased milk yield, dullness or other signs of toxemia) and fever > 39.5 degrees C, within 21 days after parturition. Animals that are not systemically ill, but have an abnormally enlarged uterus and a purulent uterine discharge detectable in the vagina, within 21 days post partum, may be classified as having clinical metritis. Clinical endometritis is characterised by the presence of purulent (> 50% pus) uterine discharge detectable in the vagina 21 days or more after parturition, or mucuopurulent (approximately 50% pus, 50% mucus) discharge detectable in the vagina after 26 days post partum. In the absence of clinical endometritis, a cow with subclinical endometritis is defined by > 18% neutrophils in uterine cytology samples collected 21-33 days post partum, or > 10% neutrophils at 34-47 days. Pyometra is defined as the accumulation of purulent material within the uterine lumen in the presence of a persistent corpus luteum and a closed cervix. In conclusion, we have suggested definitions for common postpartum uterine diseases, which can be readily adopted by researchers and veterinarians.