Kvet Forum
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Puerperal metritis should be defined as 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 toxaemia) and fever of >39.5°C, within 21 days after parturition.
Aetiology
Puerperal metritis commonly affects cows after unhygienic manual interference to correct fetal malpresentation/malposture, after delivery of twins or a dead calf and following infectious causes of abortion (e.g. Salmonella spp.). In most of these situations there is retention of some, or all, of the fetal membranes.
Cows suffering hypocalcaemia during second-stage labour have an increased incidence of retained fetal membranes and metritis. Illness follows bacterial entry and multiplication within the uterus, with the production of toxins that are absorbed across the damaged endometrium.
The likelihood of metritis increases in proportion to the duration of manual intervention in dystocia cases.
Clinical Presentation
Acute puerperal metritis often presents 2–4 days after calving. The cow is dull and depressed, inappetent and with milk yield typically about one-third of that expected.
The cow is febrile with a rectal temperature often above 40°C; however, severely toxic cows may have a normal or subnormal temperature. Straining may be noted in those cows with retained fetal membranes.
There is often fetid diarrhoea, but no evidence of blood or mucosal casts in the faeces. The mucous membranes are congested and there are reduced ruminal sounds.
The vulva is swollen/oedematous in dystocia cases, with evidence of a red/brown fetid fluid discharge. Typically, the fetal membranes are still partially attached to the uterine caruncles. The uterus may contain up to 5–10 litres of red/brown foul-smelling fluid.
Diagnosis
The provisional diagnosis is based on history, clinical findings and elimination of other common diseases. Vaginal examination often stimulates discomfort and vigorous straining and reveals copious amounts of red-brown fetid fluid.
Differential Diagnosis
Differential diagnoses to consider for inappetent and recently calved cows could include toxic mastitis, salmonellosis, ruptured uterus if considerable difficulty is encountered during delivery of the fetus, acidosis if sudden access to concentrates post calving, peritonitis, retained twin calf, hypocalcaemia/fatty liver syndrome and displacement or torsion of the abomasum.
Treatment
Typical treatment comprises intravenous oxytetracycline and NSAIDs, with intramuscular oxytetracycline for the following 3–4 days. Ceftiofur is another commonly used antibiotic. In toxic/dehydrated cows, rapid intravenous infusion of three litres of hypertonic saline is indicated and clean drinking water must be readily available. Calcium borogluconate may be required to treat associated hypocalcaemia. Intrauterine pessaries containing antibiotics are commonly used, but there is little supporting evidence for such treatment. Uterine siphoning/lavage with saline is used by some practitioners, but it must be done with care to avoid further endometrial damage and toxin absorption. The prognosis is variable for cases of acute toxic puerperal metritis and fatalities are not uncommon despite treatment.
The farmer is advised to call a vet for a pre-breeding check 21–28 days post calving, when clinical endometritis can be treated, if present, with antibiotic wash-out or prostaglandin injection.
Almost without exception, farmers’ attitudes to overall hygiene standards during dystocia correction could be greatly improved, thereby avoiding many of the problems encountered after such interference.
Veterinarians should wash their hands in an antiseptic scrub solution and consider using arm-length disposable gloves prior to correction of all dystocia cases. Reducing dystocia by sensible sire selection and avoiding risk factors for retained fetal membranes will also reduce the risk of puerperal metritis.