OOn a dairy farm, many antibiotics are used to treat clinical mastitis. However, selective treatment of mild and moderate clinical mastitis, after diagnosis of the pathogen, can significantly reduce this use.
Treat benefits selectively
In mild and moderate udder infections with gram-negative bacteria, yeasts, fungi and mycoplasma, treatment with antibiotics is of little use. A rapid diagnosis of the pathogen therefore makes it possible not to treat such infections with antibiotics and thus to reduce the use of antibiotics. In this way, the use of antibiotics on a dairy farm can be significantly reduced. Various studies have already shown that on farms with many gram-negative udder infections, the reduction through selective treatment can amount to more than 50%! An umbrella study eventually bundled all the results of the different studies to draw a general conclusion about the effects of selective treatment.
Ready for practice?
In the last 10 years, various rapid tests for germ detection have come onto the market that make it possible to quickly determine the pathogen of an udder infection in a milk sample. Based on such a rapid determination, it can then be decided whether or not to treat the cow with antibiotics.
To increase application in practice, it is necessary to also know the disadvantages of selectively treating clinical mastitis. To get a broader picture of the effect, a team of international researchers compared the results of 13 comparable studies to form one general conclusion about the effects of selectively treating non-severe clinical mastitis.
Treat disadvantages selectively?
In the 13 studies, the cows with non-severe clinical mastitis were divided into 2 groups. One group was immediately treated with antibiotics (= blind treatment, without bacteriological examination). The other group was treated or not with antibiotics based on the results of a rapid test. In the latter group, a milk sample from the infected quarter was first examined using a rapid test for germ detection. With this test, a result can be read after 24 hours and – depending on which germ is visible – decide whether or not to treat with antibiotics.
The studies showed that selective treatment has no adverse effects on udder health. After 14 or 21 days, the pathogen had completely disappeared in a similar number of cases and the number of new infections with other bacteria was also comparable to the group of cows that were immediately administered antibiotics. In the longer term, cows from both groups were also found to contract a new udder infection equally often.
The somatic cell count in the milk was at a similar level in the different treated groups of cows. The milk production of the two groups was also not significantly different. Finally, selective treatment of clinical mastitis also did not lead to an increased culling of reformed cows.
Lower antibiotic use
By combining the results of 13 studies, it could be demonstrated that selective treatment of non-severe clinical mastitis has no adverse effects on udder health compared to conventional treatment.
Milk production, somatic cell count, relapses or new infections and culling of cows appear to be unaffected by the choice of treatment type. Selective treatment of non-severe clinical mastitis based on rapid germ detection diagnostic tests is therefore an equivalent alternative to classical treatment. It leads to a lower use of antibiotics without risks for the health of the cow or milk production.
Bron: Selective treatment of nonsevere clinical mastitis does not adversely affect cure, somatic cell count, milk yield, recurrence, or culling: A systematic review and meta-analysis. De Jong et al. Journal of Dairy Science Vol. 106 No. 2, 2023