Endometritis is relatively common infection of the uterus following calving. We often term cows with endometritis ‘Dirty Cows’. ‘Dirty Cows’ do not show any signs of being sick and they look like normal healthy cows. We can identify the these by using a quick, cost effective and simple method called metrichecking. 
 
As a rule, ‘at risk cows’ that have had retained foetal membranes (RFM), twins, milk fever, an assisted calving and/or a dead calf, are more likely to be ‘dirty cows’. However, when whole herds are metrichecked, up to 71% of cows that were metricheck positive, were considered ‘not at risk’. Research into prevention of endometritis is ongoing. 
 
The whole herd prevalence of metricheck positive cows can vary greatly, with some herds only have a few positive cows and others having between 25 to 50% of the herd metricheck positive. In a recent study of 100 New Zealand herds, the average metricheck positive cow prevalence was reported to be 25%. 
Endometritis results in lower conception and 6-week in calf rates, higher empty rates of up to 30% and if they do get pregnant it can take 2 to 3 weeks longer than cows without endometritis. There is a positive return on investment to whole herd metrichecking when there are more than 2% of dirty cows treated, which is probably >95% of herds in New Zealand. 
 
Traditionally we have metrichecked the whole herd in one visit around 35 days before the start of mating, to give the treated cows time to cure before mating starts. A recent New Zealand study looked at metrichecking in batches starting two to four weeks following calving. This resulted in a 9.6% improvement in the 6-week in-calf-rate and a 3% higher 12-week in-calf-rate, compared to late treated cows i.e. cows treated a month prior to mating. So there are some real positive benefits for identifying and treating cows early. 
 
The most common treatment is with an intrauterine infusion of antibiotics that has a nil milk withholding. Talk to your Vet about your plan for metrichecking this year, there are some real positive reproductive benefits from identifying and treating ‘dirty cows’ early.