A silent burden
When it comes to what is the biggest cost for any dairy farmer, the answer will always be feed (most of the time). But here we focus on post-calving infection (and its ramifications) that silently affects next season’s in-calf rates.
Uterine infection/endometritis is a major player in pulling the in-calf rate down. It is estimated that the cost to lift the in-calf rate to more than 70% for the dairy sector is about $110 million annually.
How common is it?
In 2015, Dairy NZ and partners examined 1806 cows across 100 herds in Waikato and Canterbury 30 days before their planned start mating.
The result was 25% of the cows tested by metrichecking were positive for having an infection inside the uterus with a herd level prevalence varying between 5 and 65%.
But the most important question is which cow is more likely to be affected? Usually, farmers are focusing on checking the cows at risk – those with difficulty calving, retained membranes or metabolic issues- but when a whole herd was tested, 71% of positive cows are not withing the at-risk group.
When should metricheck be carried out?
Not too late and not too early.
A New Zealand study recommends it is not done before 2 weeks after calving as discharges may affect the scene and not too late (6 weeks plus) as the uterus and cervix close, sealing discharges inside. The recommendation is to perform it in batches 2-3 weeks after calving and one final whole herd test to check for later infections or cows that didn't respond to the initial treatment.
What is the impact of opting out?
According to Dairy NZ, the overall reproductive performance was significantly reduced for cows who scored 3 or more on metrichecking.
That can be translated to a 7% reduction in 3 weeks submission rate and 20% reduction in 1st AI conception rate.
Subsequently, 3 and 6 weeks in calf rate were 18 and 26% less than normal herd mates.
Conclusion
Endometritis is common, mostly hidden, and expensive if left undiagnosed or untreated. The estimated loss for a herd of 500 cows with 25% prevalence is about $9000 yearly.
So, don't guess which cow is dirty; check, do it in batches, and do it early.
By Mo Irsheid
