These cows typically have a creamy pussy discharge when 'Metrichecked' and may outwardly look to be in good health. Even just a few flecks of pus on a 'Metricheck' device indicate that infection is present. The longer these second stage infections remain undetected the greater the chance the cow will become infertile.
Long standing uterine infections cause permanent uterine scarring. Recent trials have shown that those cows treated 1-3 weeks post calving have far better reproductive results than cows treated 4-8 weeks post calving.
The majority of uterine infections will have become undetectable 4 weeks post calving, even when using a 'Metricheck' device. The infection however remains present deep inside the uterus. These 'hard to detect' cows still have very poor fertility. Early checking will considerably increase the chance of finding these 'dirty' cows.
All 'At risk' cows (RFM's, dead calvings, assisted calvings, vaginal discharge, twins) should be treated with a 'Metricure', 2-4 weeks post calving.
The rest of the herd should be 'Metrichecked' 7-28 days post calving. Careful planning must be done to ensure calving groups can be identified for checking. A sensible rational would be to identify cows calving up to the mid point and 'Metricheck' these 1-2 weeks after this date - e.g. August the 20th-25th. The third quarter to calve is then marked again and checked 3 weeks later on about the 5th of September and the final quarter around another 3-4 weeks later on about the 5th of October.
Metricheck devices may be purchased or lent or you may use your vet to detect and treat during the same milking.