by Gabe Middleton, DVM
As most of you have begrudgingly found, the availability of dry cow antibiotic tubes has been drastically challenged due to numerous factors. It appears as though the shortage will continue into the foreseeable future. Dairy producers should consider looking at this as an opportunity instead of a frustration. After all, this may be the future direction of the industry and may even become mandatory at some point. Europe has drastically reduced dry cow therapy and in some cases they have eliminated it. They have not seen a corresponding increase in somatic cell count.
A great option for dairies with dry cow tube supply issues is to (re)consider selective dry cow therapy. This has been discussed quite a bit in the industry over the last few years. It appears as though it’s going to gain ground out of necessity. There are a few pieces of information that a dairy needs to know to make the right treatment decisions. How do we find the cows that need the antibiotic tube? Chances are, only 10% – 20% of cows actually need treatment.
Monthly SCC using test day data is a fantastic way to determine what cows need treatment. Obviously, if she currently has a SCC above 250,000 she is considered infected. Even if the cow has had a spike in SCC during that lactation or a clinical event she should qualify for treatment as well. All cows, even ones that were not given antibiotic tubes, should be given a teat sealant and a coliform mastitis vaccine at dry off.
I have witnessed disasters as a result of selective dry cow therapy. Three days after dry off the cow is dead in the stall due to toxic mastitis. This situation certainly wipes out any savings that the program has created. Situations like this are preventable. There is a high likelihood that when someone gave that cow the internal teat sealant, she also received a dose of E. coli in the udder accidentally. Whatever person is in charge of dry off needs to be properly trained and monitored. They need to understand the importance of a clean teat end. It is best practice to use 4×4 alcohol-soaked gauze sponges to clean teat ends instead of the alcohol wipes provided in the sealant box/pail. The 4×4 sponges are more abrasive and do a much better job cleaning manure off the teat. The cow’s udder should be recently milked prior to infusion and the teats should be post-dipped afterward.
If a herd does not have monthly SCC data on individual cows, they can perform on-farm or lab-based culture of those cows prior to dry off to determine who has an infection, therefore making antibiotics therapy necessary. This process is much more cumbersome but it is certainly effective at finding the cows who need treatment.
If a dairy properly cleans teat ends, identifies what cows need treatment, post-dips cows after dry off and has a clean, dry bedding area for dry cows, there is no reason why this protocol can’t be effective at preventing new infections. I suspect some dairies that try this system out of necessity will continue with selective therapy even after tubes are more widely available.
Lastly, make sure that results are monitored. There are many ways to do so and all have some value in the analysis.
The new infection rate over the dry period metric measures last test SCC from last lactation and the first SCC in the current lactation. The goal is less than 8% – 10% for most herds. Also look at clinical mastitis rate in the first 60 days in milk; the death rate due to mastitis in the first 60 days in milk; and the survivability of the cow up to 120 days in milk.
If you measure those trends over time, it will provide insight if dry cow therapy is really even needed in the first place. Perhaps the selective approach is better and becomes the industry standard in the future.