Kiwis lead mastitis research
As Kiwi scientists crack a long-standing barrier to simple mastitis treatment, South Taranaki dairy farmers are taking part in a nationwide trial aimed at reducing the use of antibiotics to treat the condition.
The Taranaki Veterinary Centre is one of about half dozen clinics taking part in a study aimed at finding a way to cut back on antibiotics without negatively impacting the overall cure rate, chief executive Stephen Hopkinson said.
Fourteen farms were enrolled in the trial through TVC’s Manaia branch, and it was hoped at least 400 cases of mastitis could be studied, some treated without having a sample cultured and some using a treatment based on the results of a culture.
After treatment, all cases would be sampled and cultured to determine the exact cure rate.
The aim of the study was to see if culturing cases of clinical mastitis and selecting an antibiotic based on the culture results and the type of bacteria grown could give better cures and use fewer antibiotics.
It was hoped that by using cultures, less antibiotic would be used, cheaper antibiotics could be used with more confidence, less milk would be thrown out and there would be no negative impact on the cure rate.
Mastitis control accounts for more than 85 per cent of antibiotic use on New Zealand dairy farms, with about half administered at drying off.
Research into mastitis prevention and treatment is ongoing and the launch of a worldfirst ready to use penicillin formulation confirmed New Zealand scientists were at the forefront, Bayer dairy veterinarian Ray Castle said.
Penethaject RTU (ready to use), a form of penicillin injected into the cow’s muscle, does not need pre-mixing and is the first formulation of its kind anywhere in the world.
Castle said the product would make it easier for farmers to effectively treat clinical mastitis, a condition affecting 10 to 20 per cent of New Zealand’s five million dairy cows every year.
‘‘The active ingredient, known as penethamate, previously came in powder form and had to be mixed together with a liquid by the farmer or veterinarian to create an injectable solution,’’ he said.
‘‘Developing a pre-formulated version had been a scientific challenge for many years until scientists in Bayer New Zealand’s laboratories worked with Otago University to create a stable formulation, something that had never been achieved before.’’
Castle said penethamate was stable long term as a powder, but not as a liquid.
‘‘The challenge was to create a liquid formulation in which the active ingredient remained stable and active without caking or sticking together in clumps.’’
‘‘The whole process, including clinical trials, stability testing, registration and commercial manufacturing, took about seven years to bring to fruition. It’s a world first and something that confirms New Zealand’s position as a leader in dairy science.’’
Castle said the chemistry in Penethaject allowed antibiotic concentrations to build up in a cow’s udder. These concentrations were up to 10 times higher than those achieved by other penicillin formulations, allowing the antibiotic to directly work on the mastitis bacteria, particularly Streptococcus uberis, the most common bacteria responsible for mastitis in New Zealand.
Once the mastitis was treated, the antibiotic quickly left the milk, allowing the cow to be back in milk production, in some cases after 48 hours.