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The Dirty Cow

Guan Tan, Hamilton

As we roll into September, the city folk all start talking about the start of spring; farmers on the other hand, have had their heads down working hard through the majority of their spring calving already.  It’s definitely the busy season, with calving, milking, & calf rearing underway.  In the thick of it all, it may be painful to add another chore to the list, but mating is just around the corner as well, which invariably leads to discussions about fertility and benchmarks.

There are a variety of reasons that animals may not be getting in calf or even cycling.  Major causes range from low body condition scores & poorly grown heifers, to maiden heifers needing an extra 10 days post-calving to recover compared to older animals.  Another major factor that can still be managed is the dirty cow –animals with a post-calving uterine infection.  Endometritis is the term for such infections that are not otherwise affecting the animal enough to make them ill.

A national study completed in recent years found that when cows from 100 herds were metri-checked 30 day before mating, there was a 25% prevalence of test positive cows.  As you would expect, these animals had lower conception & in-calf rates than their healthy counterparts, with higher metri-check scores correlating to poorer reproductive performance.  Research has found that that not only do dirty cows take weeks longer to get in calf, they still have empty rates 10-30% higher than clean cows.  As such, we want to find, treat, & cure affected animals as soon as possible in order to give them the best chance of getting in calf early.

“At Risk” cows are those that stand the highest chance of developing a uterine infection.  This group includes all animals that meet any of the following criteria: late calvers, twin bearing, assisted calvings, retained membranes, metritis, mastitis, metabolic conditions, and stillborn calves.  Such animals are the primary candidates for pre-mating checks.  It is important to note that while the at risk cows are the prime suspects, plenty of cattle with no recorded health issues may also be carrying an infection (71% of test-positive animals are not considered at risk)!

Metri-checking is a quick & simple test to pick up infections.  Kiwi research corroborates that earlier detection & intrauterine treatment in affected animals leads to better reproductive outcomes.  Batch checking of animals two weeks post-calving led to almost a 10% higher in-calf rate than traditional whole herd checks, which were again much better than in-calf rates without metri-checking.  To be most cost effective, metri-checking is best performed 35/+ days before PSM, so that treated cows can cure before scheduled mating.  Please give your local Vetora clinic a call if you want to discuss metri-checking, as our vets will be happy to show you how & why it will be a worthwhile investment if just 2% of your herd is affected.