A clinical approach to winter animal health
The blanket use of dry cow therapy looks set to be replaced by a more scientific approach based on clinical need and the availability of accurate data
Published 21/10/2015 | 02:30
'What's the best way to dry off my cows?' is not a question I get asked too often. Instead, it's likely to be 'what's the best tube?' The answer is that it depends. Every farm is different, and a good dry cow therapy for one farmer may not be for another.
A question that every farmer should ask themselves before using any dry cow therapy is why am I using this particular therapy on this particular cow at this particular time? Is it price? Withdrawal times? The one I used last year? The one the neighbour uses?
With antimicrobial resistance becoming a bigger and bigger issue, the blanket use of dry cow therapy may not be around for too much longer. The wave of opinion is that this not a prudent way to use antimicrobials, nor is it always warranted.
So as an industry we must prepare for a time when antimicrobial use at drying off will be based on clinical need and justifiable by the availability of accurate data.
The concept behind dry cow therapy is to treat existing infections that have not been cured during lactation and to reduce the number of new infections that may occur after drying off.
This is done using antibiotics and non antibiotic products (sealers).
The antibiotic tubes are used after the last milking and are designed to have a prolonged effect and enhanced penetration in the udder, to increase the chances of curing chronically embedded infections.
So how do you decide what is the most appropriate method of dry cow therapy on your farm? The minimum detail needed before any therapy is purchased is the pregnancy status of each animal. Using dry cow therapy on empty cows is an unnecessary cost if they are simply going to be culled.
As an aside, a large percentage of culled cows are mistakenly believed to be empty.
Some cows will continue to cycle normally throughout pregnancy so it is important not to rely on observation of bulling as the only method of pregnancy diagnosis.
In nearly every herd I scan for pregnancy there are cows pregnant that the farmer has observed bulling recently. Get your cows scanned early so these costly and preventable mistakes are avoided.
After scanning, you must find out what bacteria are causing the increase in cell count on your farm.
This is done by performing a culture and sensitivity test on sterile samples taken from at least 10 cows.
Using a bulk milk sample in conjunction with samples from the higher cell-count cows is the best way to do this.
This is performed before the drying-off period to provide a profile of the bugs and their respective sensitivities to various antibiotics.
Sometimes you may be dealing with single infection while other times mixed infections exist.
The most commonly used method of drying off cows is blanket therapy.
This involves using an antibiotic tube with or without a sealer on all cows regardless of days in milk or pregnancy status at the same time.
This method does have its advantages but in the post quota era where production constraints have disappeared, it will become less and less relevant.
Why dry off a later calving cow too early? A prolonged dry period, producing a fat but not fit cow at calving brings its own problems.
The method which will become more prevalent in the future will be selective therapy.
Milk recording data throughout the year will show the days in milk, milk production levels, and when combined with pregnancy status, and culture and sensitivity tests, decisions can be made to get the most favourable outcome.
Prudent use of antibiotic therapy will benefit all in the industry in the long term, but it will only be possible with accurate analysis of the relevant data.
Troubleshooting: I've vaccinated and dosed and I'm still getting problems - Why?
This is a huge contributor to the development of illness in cattle. Stress, in whatever form, decreases the immune system. Examples include abrupt weaning, sudden dietary change, but the list is endless.
The correct product
Ensure the product you are using is correct for the diseases/parasites present on your farm.
All pneumonia vaccines should be completed at least two weeks prior to housing, including boosters.
Not using the product according to manufacturer's specification causes a lot of problems. For example, the IBR live virus must be used within four hours of mixing. Accurate estimation of weight is vital when dosing for fluke and worms.
The national eradication programme is paying dividends, but BVD persistently infected (PI) cattle are still being retained on some farms. These animals are shedding massive quantities of BVD virus and will depress the immune system of in-contact stock.
Poor quality fodder or incorrect diet formulations can have a severe effect on stock. Young stock not thriving or dairy cows not milking to full potential due to nutrition imbalances can have depressed immune systems as a result.
Copper deficiency has been linked to increased incidences of pneumonia in young stock. Mineral imbalances around calving time can result in clinical and sub-clinical milk fever in dairy cows which can put severe pressure on the immune system.
Lack of air movement in sheds through poor design or overcrowding is a perfect environment for both viruses and bacteria to thrive.
All sheds should be power washed and fully disinfected before stock are housed. There are any number of disinfectants on market.
There is now an increased awareness that every farm should have a detailed herd-health plan in place. Your vet is best placed to deliver this plan as they visit your farm on a regular basis, have all the diagnostic tests at their disposal, and can put a plan in place individually tailored to your farm. Prevention is better than cure, so a minimum investment now could save a significant amount of money in the future.