How vets can help manage change to selective dry cow therapy

Change can be welcomed or resented. Everyone gets excited when they get a new car and younger people can’t wait for the latest version of their mobile phone. However, I didn’t hear too many people getting very excited about the additional bureaucratic requirements to carry on with TB testing. There will be a mixed response from farmers and vets to selective dry cow therapy.

Mary McAleese, a former president of Ireland, said there are two types of people: radiators of hope and drains. At the moment, the majority of dairy farmers are likely to fall into the drain category – they work long hours, the milk price has fallen by a third and there is no sign of when this trend is going to be reversed. It must be a very frightening time to be a dairy farmer and it’s helpful to remember this when we visit farms.

Just imagine how the farmer is feeling when you arrive on farm; if you get out of the car and are equally depressive, then you both are likely to feel pretty lousy by the time you leave. If, however, you have a positive and optimistic outlook, then you can help change the farmer’s mood and make him or her feel better – even if it’s only for a short period of time.

Antibiotic resistance

We all know, deep down, selective dry cow therapy makes sense and is what all dairy farmers should be doing. Dame Sally Davies, the senior medical officer, tells us more than 20,000 people a year die as a result of antimicrobial resistance in the UK. The golden era of new antibiotics being developed has long since passed and no new antibiotics are in the pipeline. So anything that contributes to antibiotic resistance developing has to be scrutinised, and this includes blanket dry cow therapy.

Many countries, such as Denmark and other Nordic nations, never recommended blanket dry cow therapy. Others, including the Netherlands, have been forced by their governments to reduce overall antibiotic use and use of third and fourth generation cephalosporins and fluoroquinolones – some of the critical antibiotics. They have made significant progress in the past five years, reducing use by 50% and dropping use almost totally of these antibiotics.

Blanket dry cow therapy was introduced when the majority of cows had subclinical infection. It was one of the key components of the National Institute for Research into Dairying’s five-point plan. Cell counts have fallen considerably and now it is the minority of cows that have infections at dry-off. This means the majority of cows get no benefit from receiving dry cow therapy.

Many thought antibiotic dry cow therapy prevented new dry period infections. We know from all the research work this is not the case. We also know those farmers who use an internal teat sealant reduce clinical mastitis by between 25% and 30% in the following lactation. However, while the majority of cows get antibiotic dry cow therapy, more than 50% of cows get an internal teat seal. It makes sense to try to change these percentages around so all cows get an internal sealant and only those that are infected receive antibiotics.

Selective dry cow therapy

There are a number of ways we can have a discussion with a dairy farmer about selective dry cow therapy. You could take a view that this is a forced change you do not agree with and do not think it can make any difference whatsoever to stopping antimicrobial resistance from developing. You might even be concerned it is doomed to failure and the farmer is going to end up losing cows if he drops dry cow therapy. However, selective dry cow therapy will become the norm very soon and so vets can decide to lead on this or follow.

The alternative viewpoint is to highlight the benefits from selective dry cow therapy, of which there are many. One of the greatest benefits will come from an increased use in internal teat sealants in herds that have never used these before. These herds will see a reduction in clinical mastitis in the following lactation.

All farmers should be using internal teat sealants, as we know many cows have open teats shortly after dry-off. Work in the US has shown two thirds of cows giving more than 21 litres at dry-off have open teats seven days later. At least 20% of cows have open teats six weeks after dry-off. We know there is a significant increase in risk from dry period infections immediately after dry-off and before calving. If all cows were to receive an internal teat sealant it would have a massive impact in reducing clinical mastitis, which farmers find very depressing and frustrating, and it would improve animal welfare. Lower clinical mastitis also means reduced culling and if you can prevent the toxic cases around the time of calving you can also decrease deaths and expensive and time-consuming treatments.

Research has shown when you provide antibiotic dry cow therapy to low cell count cows, the risk of Escherichia coli mastitis developing increases in the following lactation. This tells us antibiotic use in these cows is contraindicated.

Sometimes cows will calve early and, if they received antibiotic dry cow therapy, milk has to be discarded until the withdrawal period has passed. If a cow only receives an internal teat seal then early calving poses no problems in putting milk into the bulk tank. Bulk tank antibiotic residue failures have remained at a constant percentage for many years. This now is a significant cost and problem to a dairy farmer and so anything that can be done to reduce or minimise this risk must be welcomed.

There is always a risk of introducing infection through the teat end when tubing cows – especially if these have not been thoroughly disinfected prior to infusion. The teat canal is 6mm to 10mm long and is the primary defence mechanism in stopping bacteria entering the udder. If there is any damage to the teat this will increase the mastitis risk. Infusing one tube of teat sealant instead of two tubes at dry-off has to be good for the teat end and also reduces any risk of introducing mastitis into the udder.

Calves will ingest traces of antibiotics from colostrum in cows that received antibiotic dry cow therapy. This cannot be good for the gut flora. Reducing antibiotic use must, therefore, be an advantage to the future health of the gut flora of newborn calves.

The world has become paranoid about food safety. The majority of consumers are unaware about blanket antibiotic dry cow therapy and may be shocked to know antibiotics are being given to healthy animals. This could add weight to the proposal by many in the EU and elsewhere to decouple dispensing from prescribing. In many countries in the EU vets are not allowed to dispense at all and, in Denmark, vets are not allowed to profit from dispensing.

We should ensure we only target infected animals for antibiotic treatment. Many farmers will take great satisfaction in helping to protect the food safety of milk – minimising any contribution to antimicrobial resistance.

Financial saving

Finally, there is a cost saving. This saving will be a reduction in the number of antibiotic dry cow tubes used, but they can also be a saving by reducing clinical mastitis from increasing the use of internal teat sealant.

Let’s take two hypothetical herds of 100 cows. Both have culling rates of 25%, a cell count of 150 and a mastitis rate of 40 cases per hundred cows per year. Herd A has always used a combination of antibiotics and internal teat seals at dry-off. Selective dry cow therapy might reduce the percentage of cows receiving antibiotics at dry-off by 50%, or about 40 cows. This might not seem very significant and hardly worth the effort; however, let’s look at this from a different angle. Assume antibiotic dry cow costs £7 a cow. The total saving is £280, or enough to vaccinate the herd against bovine viral diarrhoea. This is a simple cost substitution with benefits.

Herd B has only been using blanket dry cow therapy. Again, there will be a saving of £280 from dry cow tubes; however, there will be increased costs of about £450 if he uses internal teat sealants on all cows at dry-off. So it appears this farmer is out of pocket by £170 by moving to selective dry cow therapy.

But it is not quite that simple. This farmer has a mastitis rate of 40 and with a 25% reduction in clinical mastitis from using teat sealants he will save 10 clinical cases in the next year. If each case of mastitis costs him £200 then the saving is going to be £2,000. So the additional £170 generates a saving of £2,000 and so is giving more than a 10-fold payback plus less mastitis disrupting milking. This is a very attractive proposition to any dairy farmer. Farmers who start to use internal teat sealants are those who will have the greatest payback and benefits from moving to selective dry cow therapy.

The role of the vet in helping farmers move to selective dry cow therapy cannot be underestimated. We all have choices; do you want to be a radiator or a drain? If you choose to be a drain then you are unlikely to be helping your dairy farmers. Positive attitude, even at difficult times like this, can have a massive impact in helping the farmer manage the change to selective dry cow therapy.