Farmers gather to hear latest on minimising endometritis

Farmers now have the tools to look for dirty cows after calving, presenting only problem cows to the vet, which makes it more cost effective to search and treat for endometritis.  Vets speaking at a farmer meeting this week explained some of the latest thinking from New Zealand and how to apply that on UK farms. 

By FW reporters

Endometritis – if you don’t look for it, you won’t find it. But those milk producers who do, can save time and money by carrying out their own post-calving checks to identify dirty cows.

Presenting only these problem cows to the vet at the routine fertility visit is more efficient and treatment is based on what is found at that check, says vet Rachel Risdon of Westpoint Veterinary Group in Cornwall. “A mix of clear mucus and white pus before 26 days calved may self cure, but from 26 days, it is definitely worth treating even if there is only some pus with clear mucus,” she told the group.

Metritis is an acute infection within the first 21 days after calving, resulting in a sick cow and a large volume of infected fluids in the uterus. Mrs Risdon explained that the majority of cows – over 90% - will have some infection in the uterus 1-10 days after calving. That’s normal and most usually self-cure within three weeks. However, some infections are persistent for many months. “Endometritis is a chronic low-grade infection of the uterus lining. There may be some discharge behind the cow, but usually no obvious symptoms. US data shows that cows with endometritis were 73% more likely to be culled for reproductive failure, while New Zealand work backed this up showing they took an average 43 days longer to get pregnant.”

Further US studies showed that almost one-third of cows have a discharge when examined internally by vaginoscope (this lets you look at the cervix). But when cows were only examined externally, just 22% of these infected cows were picked up. “So actively looking is crucial, or you will miss them,” she stressed.

Cows that develop endometritis can be predicted by looking at their calving history and labelled at-risk (see box). Finding out whether they are clean or dirty after calving is then possible by manual examination, scooping along the vagina with a gloved hand. Alternatively, Mrs Risdon suggested performing a Metricheck test. This was developed in New Zealand and is a stainless steel rod with a rubber cup at the end. It collects a sample of mucus from the vagina, near to the cervix where infection gathers. It’s fast, sensitive and can be less traumatic and cleaner than a gloved hand, she added. She recommended farmers get their vets to show them the correct technique – gentle, clean, using a clean glove and lubricant for every cow – and how to read the results.

Once dirty cows are identified, treatments are highly effective. The only licensed antibiotic – given as a washout – is cephapirin (Metricure®) which kills most of the common bacteria causing the infection. Studies have shown an improvement after treatment in 80% of cases although if infection is moderate to severe, then cows may need re-treating to be 100% clean.

RISK FACTORS FOR ENDOMETRITIS

• Difficult calving
• Twins
• Retained foetal membranes
• Milk fever
• Ketosis
• Displaced abomasum
• High milk protein %
• Caesarean
• Cows in negative energy balance

Subclinical milk fever could be the reason why some cows go on to develop endometritis, according to Sussex-based vet Rob Drysdale from Westpoint Veterinary Group talking at the same meeting. He reported that he rarely sees classic milk fever cases these days, but is finding more subclinical cases which lead to retained foetal membranes – a risk factor in endometritis.

High yielding cows, in particular, have to make a more extreme effort to mobilise body reserves of calcium after calving, going from maintenance requirements to maintenance plus 2g/litre of colostrum. Achieving a higher litre output can make them more inclined to milk fever.

“When we look closer, the subclinical form of milk fever can usually be traced back to transition cow management and ration changes which lead to low blood calcium. This affects muscle function and the uterus’s ability to push the foetal membranes out. In addition, we do see intermittent cases of left displaced abomasum (LDA),” explained Mr Drysdale.

But managing the herd to prevent this needn’t be difficult.  Something as simple as switching to a fresh silage clamp can subtly alter mineral balances, he explained. “Whole groups of dry cows can be affected. Last autumn’s mild conditions produced lots of grass and many cows weren’t switched onto a transition ration until 10 days before calving – not long enough to adjust.”