In the last number of days I’ve received a number of phone calls from farmers who have identified Mycoplasma bovis as a problem in dairy cows.

This week I visited two farmers who described to me how mastitis started to be a big problem over four weeks ago.

As normal when a mastitis case arises, one of the farmers started treating cows that had clinical signs (clots in the milk) with antibiotics tubes and injections. However, these cows were not improving, and their quarters were swollen and hard.

Eventually, about 15 cows were so badly infected and quarters were so swollen that only a watery fluid was coming out.

At that stage the farmer was at his wits’ end and didn’t know where to turn. Given the poor response to antibiotics and chronic infection, he had no choice but to separate these cows from the herd and attempt to dry them off.

During the process he consulted his Teagasc adviser regularly about potential herd health implications and talked to his local vet about the variety of drugs used that were not working.

Cost of solving the problem

The farmer estimates that, between call-outs and drug usage, he has spent over €5,000 in the space of the last four weeks trying to solve the problem.

Additional milk samples have been taken to culture the cause of the mastitis and results are due back this week. Initially, E coli mastitis was thought to be the cause of the problem, as mastitis symptoms were very similar.

About two weeks after the bad mastitis started, the farmer also began to see signs of swollen knees and fetlocks in some of his milking cows.

These cows began to move very slowly, and the farmer found it a struggle to get the cows out to a paddock close to the parlour.

He now has another seven cows with swollen joints apart from the 15 cows with very bad mastitis.

Likely cause

The thinking at the moment is that the cause of the problems on this farm is Mycoplasma bovis.

Preliminary tests have shown the presence of this bug, and more tests will probably confirm this theory later in the week.

Typically the clinical symptoms are abnormal swelling of the knees, ankles, etc. Thankfully it’s relatively uncommon, but there are sporadic cases in dairy and suckler herds each year.

Stress triggers

Some experts suggest the infection is triggered by some sort of stress for one reason or the other – maybe poor-quality feed, not enough cubicles or not enough feed space. Normal antibiotic treatment is little or no good in fighting the infection.

If diagnosed very early some anecdotal evidence suggests a combination of oxytetracycline hydrochloride and tylosin tartrate can help.

However, from talking to farmers who have experienced the infection, many say drugs are of no use.

They advise others to get cows showing symptoms of Mycoplasma bovis out into a sheltered paddock and to keep them well fed.

Vets advise that if Mycoplasma bovis is diagnosed as the cause of the mastitis infection, there is little or no option but to dry off the cows and try to fatten them for culling.

On the other hand, cows with swollen joints will improve and these cows can return to normal and go back in-calf, but it can take a number of months.

The bigger picture

When I sat down at the kitchen table on this family farm, the devastating effect of a herd health problem like this became apparent.

All family members had almost come to the conclusion that they were getting out of milking cows and moving to a beef-and-sheep enterprise.

They had built up a very significant dairy enterprise from scratch and had cared for and tended to animals all their lives.

Facing the shock of a herd health issue

All of a sudden they were landed with this massive herd health issue. They were struggling to make any sense of the matter, with new cases of incurable mastitis every day and cows unable to walk due to severe swelling of joints.

It was as if their whole livelihood was being taken from under them. The fact they didn’t know the cause or the likely endpoint of the herd health problem caused severe distress and the inability to sleep or eat, wondering what was going to happen next.

The farm in question has grown cow numbers significantly and was stocked very heavily on the grazing platform. The intention was to bring grass in from an outside farm, but given the pressures of managing large herd size a rethink is on the cards.

Help available

I contacted UCD vet Eoin Ryan to discuss the situation. He said the case in question sounds like a very bad case of Mycoplasma bovis, which can have devastating effects on a herd.

He said: “There are a number of veterinary herd health consultants who have completed training in dairy herd health in UCD.

“They are situated throughout the country and are ready and able to help farmers with severe problems like this.”