Farmers, vets and industry professionals gathered for the annual British Mastitis Conference in Worcester last week. Louise Hartley reports from the Sixways rugby stadium.
Many milk processors are now asking farmers to consider a more restrictive use of antibiotics and if European trends are adopted in the UK, Selective Dry Cow Therapy (SDCT) will have to be embraced, either voluntarily, or through policy.
Speaking to delegates at the British Mastitis Conference, Dr Karlien Supre, Flanders Milk Control Centre, Belgium, said farmers should not be afraid to adopt a SDCT programme, but stressed the importance of correct administration.
She said blanket antibiotics are sometimes used as an insurance for good udder health, especially in higher yielding herds, or to conceal poor herd management.
But on presenting the results of her research project, she said just using teat sealants on cows within a certain criteria could reduce the use of antibiotics, without having a negative impact on udder health in the next lactation.
Dr Supre conducted an 18-month project working with four dairy herds and their vets in Belgium. The herds ranged from 51-70 cows producing between 8,000-11,000kg per lactation.
Milk samples were taken 10 days before drying off, after calving and from clinical mastitis cases.
After several adaptations, the SDCT was based on the following criteria: no clinical mastitis in that lactation, daily milk yield had to be below 15kg and the SCC for the three days prior to drying off had to be less than 100 for heifers or below 150 for cows.
Farmers were asked to use an internal teat sealant on every quarter of each cow, regardless of whether antibiotics were also being used.
Dr Supre said: “Of the 240 cows dried-off, total antibiotic use reduced by just under 20 per cent and the amount of critical antibiotics [for systemic cases] reduced by 53 per cent.
“At calving, cows which were dried off without antibiotics did not have more major pathogen infections than the antibiotic treated cows. Udder health in the proceeding lactation was measured via SCC and clinical mastitis rates.
“The results of the trial showed SDCT did not hamper udder health, with no difference between cows which had been treated with antibiotics and those which had not.”
Delegates commented on how low the SCC threshold of the project was. Dr Supre said: “In another study we looked at 40 farms using SDCT.
“The farms used their own thresholds and criteria and found heifers could be dried off without antibiotics and not encounter any problems, as long as they had a SCC lower than 300.
“For adult cows however, using teat sealants alone on anything over 250 SCC was a major risk.”
Convincing some farmers to switch to SDCT on a voluntary basis would be difficult, said Dr Supre and all delegates stressed how critical it was to consult with a vet before making a SDCT plan.
“We must provide farmers with education, guidance and confidence.”
Other vets also said giving antibiotics to a low SCC cow increased the risk of them developing gram negative clinical mastitis in the next lactation, so there were several reasons why prudent antibiotic use should be considered by dairy farmers.
Dr Supre recommended using teat sealants every time a cow was dried off, even if antibiotics were not being used.
In a questionnaire of 500 dairy herds carried out by the Flanders Milk Control Centre, only half the farms used teat sealants, and half of those used them incorrectly.
Dr Supre said: “Some farmers massaged the sealant into the udder or divided one sealant tube between all four quarters, which is bad practice.
“Consult with your vet about your antibiotic and teat sealing procedures and develop your SDCT plan with them.”
Guidelines on administration from AHDB Dairy state: