Zoetis field veterinarian Dr Greg Chambers gave vets attending this year’s Zoetis Dairy Summit an insight into the problems poor hygiene practices can inflict on cows already being treated for a mastitis infection.
“Farmers are more aware now about the need to practice best hygiene when administering teat seal, but it is fair to say many take a less than surgical approach to hygiene for mastitis treatment,” he says.
This lack of attention to detail can result in apparent treatment failure. New bacterial infections introduced while administering intramammary treatments can replace the original infection and cause even worse mastitis.
He pointed out the best practice approach was supported by both evidence and common sense.
“But it is not always that obvious that you should use good hygiene. Maybe we are taking it for granted that common sense will come into play here?
“Poor hygiene can lead to ‘superinfection’, and with it worse clinical implications than if no treatment at all was used.”
One of the most common causes of infection is the mis-insertion of antibiotic tubes. An American study showed partial insertion of antibiotic dry cow therapy syringe tips into teat canals delivered cure rates of 81% in infected cows, compared with only 56% when the syringes were fully inserted.
“Imagine if you layer poor practice and hygiene on top of that how the infection rate ramps up and the product’s performance ramps down.”
An Australian study examining the success rate for treating high somatic cell count cows during lactation highlighted this.
Of 428 high somatic cows, 214 were not treated with anything and still 2% developed clinical mastitis. The other 214 cows were treated with antibiotics and 13% developed mastitis within a week of the treatment being given.
“The treatment of those cows led to an extra 10% clinical mastitis probably caused by new infections, and highlights the need for sterility when treating them.”
He acknowledged there was not a great deal of data or trial work regarding the impact of hygiene on infection rates, possibly because the industry was assuming common sense was prevailing at treatment time.
“We as vets need to emphasise to farmers that the level of hygiene required is the same standard needed for a milk sample.”
He suspected the reason treatment standards were not what they needed to be was because treatment of cows with mastitis usually involved only a relatively small “sample” of the herd.
“Say you have 300 cows and get 40 cases of mastitis over the season, and you get a 10% increase through poor hygiene, will you notice that? Probably not.”
If the same level of infection came about through poorly administered teat seal in heifers, a farmer would “most definitely” notice it, because they would all be witnessed at around the same time.
A simple best practice process involved something similar to teat seal process – marking the animal, cleaning teat ends until swabs wiped clear, infusing with a partly inserted tube fully plunged, massaging up into the canal, then releasing cows to walk quietly from the dairy.
“It is not rocket science, and should be easy to do.”
He challenged dairy veterinarians to push on with their stewardship work on dry cow therapy, to apply it to routine mastitis treatment during lactation as well.
