Persons attending this presentation who came to find which drug to "cure " mastitis will be sorely disappointed. The purpose of this paper is to help producers delineate a rationale for their farm to deal with a problem that every dairy must account for from time to time, some, far more frequently than others.

Many years ago, Dale Hancock surveyed dairies in northern Ohio for calf scours causative agents and found that all of the farms had the same organisms present. It was only the management practices that made the difference as to whether or not this complex disease manifested itself on a particular dairy. It is a very similar situation for mastitis. Perhaps the Fram Oil Filter ad pitch of a few years ago said it best, "you can pay me now, or you can pay me later." When it comes to treatment of mastitis, the best treatment remains a vigorous program of prevention through a host of good management practices including but not limited to good nutrition, clean, dry and comfortable environmental conditions, regular vaccination, properly functioning and maintained equipment, and good pre-milking and post-milking hygiene. Prevention is the best medicine, but even under ideal circumstances, there will be some incidence of disease.

Without records, you have no mechanism to know where you've been or where you should be going. What is normal? Your farm is NOT the same as your neighbors but there have been some data gathered to use as indicators of where a "good" dairy ought to be. You should have a goal of less than 1% of your herd treated at any given time. This means that counting the withdrawal time for an antibiotic treated mastitis case and the time needed for the milk to return to normal appearances that you would be discarding milk from not more than one cow out of a hundred milked at any given time. When reviewing your herd test SCC record data, you should see an incidence of less than 10% new infections. This would mean that based on the change in SCC, that there would be fewer than 10 new infection cases per month. Obviously, these numbers will vary significantly from herd to herd, region to region and season to season. These are not unreasonable management goals since there are many dairies that can and do achieve these benchmarks routinely. That is not to infer that they do it with little effort or expense, merely that it is achievable routinely. Utilization of records helps a producer to identify those animals that have a repeat history of mastitis infection as well as serving as a barometer of how good a job the current therapeutic treatments are at achieving desired cure or response rates. While there are countless varieties of bacteria that can cause mastitis, the vast majority of mastitis infections on dairy farms are caused by a relatively few types of bacterial families. Mastitis researchers categorize most of these bacteria into two main types - gram-positives and gram-negatives based on the type of stain that they take up when stained in the laboratory. Gram-positives will at times show some sensitivity to antibiotics whereas gram-negative bacteria tend to show frequent resistance to antibiotic therapy. Examples of the gram-positive bacteria families most often seen causing mastitis are Streptococci and Staphylococci. Examples of gram-negative bacteria most often seen causing mastitis are E. coli, Klebsiella and Aerobacter species. Often, mastitis researchers will categorize the bacteria that cause mastitis by where they commonly are found to cause mastitis infections. Streptococcus agalactiae and Staphylococcus aureus are commonly referred to as contagious mastitis organisms since they are most commonly spread at milking time via a variety of means. The E. coli and other Streptococcus species are usually referred to as environmental mastitis organisms since they are most commonly found and spread in the cow environment outside the milking area. There are many additional types of mastitis causing bacteria but when they predominate the incidence of cases that are seen, they usually indicate a specific breakdown in management that allows them to infect the cows.

With such a wide variety of bacteria that can cause mastitis in the cow, it becomes very useful to know what the specific organisms are that are causing mastitis cases on a dairy. This is best accomplished by culture of infected quarters. There are many ways to accomplish this and the usefulness and significance of mastitis culturing is very dependent on what the expectations are of the persons requesting the culturing. If the expectation is that one will find a particularly effective antibiotic to use, then sooner or later there is likely to be disappointment because as an antibiotic is employed regularly to treat all cases of mastitis, there will be a natural selection for bacteria that will be able to survive the antibiotic treatment. This fact is playing heavily in the popular press headlines these days with regard to infections in humans that have in all probability been acquired from food borne bacteria. This problem is gathering more and more momentum over time and may eventually cause removal from the market of most antibiotics that are currently legally being used for therapy. This concern may also result in few if any new antibiotics ever making it to the livestock industry because the FDA is taking steps to ensure that the public health will not be threatened by livestock sources of acquired antibiotic resistant bacteria. They are attempting to ensure this by requiring a very rigorous review and categorization of veterinary antibiotics that are similar in action to those that are important to human medicine. Such concerns are not the idle imagination of this author, rather they represent the present daily reality of measures currently underway by the FDA to deal with this concern over ensuring protection of public health.

There are three "R's" that should be employed in dealing with rational treatment of mastitis on today's dairies: Records, Response and Results. The first R, as mentioned earlier is that of records. Without records, there is no measure to employ in making the decision to treat or not to treat. There is no magic medicine now or for the foreseeable future when it comes to treating clinical mastitis, however with good records, it is possible to make an informed decision about the likely chances of an animal responding to treatment. If a cow has only put milk in the tank for seven days out of the last seventy, then she has a very low probability of responding to anything that we should decide to treat her with. That same thing applies to a fresh cow that has a record of many treatments in previous lactation(s) and is back fresh with abnormal milk again. She is probably a much better candidate for the career development course at McDonalds than as a dairy cow in your herd. A cow that has been treated many times simply multiplies in many ways the odds that you will ship a violative antibiotic residue in your bulk tank as a result of some treatment foul-up. Not to mention the costs in time, labor and aggravation of all of those individuals that are involved in the treatment of such individual cows. Good individual cow treatment records allow you as a producer to see if a cow has responded to treatment and how frequently she has such problems and whether or not the cow is a net benefit to the overall profitability of the dairy. Good herd records allow a producer to look at the herd as if it were an individual and see if there is a seasonal influence on new infections as well as to determine if it is more or less than expected. They also allow producers to decide if intervention strategies have resulted in the desired reduction and response of clinical cases as well as new infection rates. They will help producers determine if there is a particular time when cows or groups of cows are having problems, thus catching troubles perhaps before they become uncontrollable.

Response is the assessment of whether or not we have seen some change as a result of your treatment. The classic example of response might be the reduction of swelling in a clinical quarter as the result of administration of an anti-inflammatory drug. Response can be either positive, negative or both at the same time. An example of it would be if our drug therapy resulted a reduction of quarter swelling but then all of the pregnant cows that we treated aborting! Then we could have created and even worse situation than we were curing. We use response measurements to see if we are actually curing cases by eliminating culture positive quarters and if the drug treatments have been effective in returning the milk to normal.

Finally, are results. Results are what the aim of our therapies hopefully achieve, namely a return to normal health and production. Therapy carries with it many potential benefits but equally as many liabilities. It is vitally important that the major effort on a dairy is prevention by knowing what the organisms are that are causing the infections and concentrating on correcting the breakdown in husbandry, management and machines that have allowed the organism to gain entry into the cows. It is crucial that personnel that are allowed to treat animals with drugs both know and understand their role and responsibilities. The fewer people that have that authority, the less the chance of human error. Persons authorized to treat should be properly trained in infusion techniques and understand and carry out completely residue avoidance procedures, including animal identification, segregation, record keeping, and withholding time information. Most dairies would benefit greatly from a training session of all people who milk cows in evaluation of mastitis cases and what to do about them. A simple triage method that allows evaluation of just how sick the cow is and what should be done about it can pay great dividends. Knowing when and what to do with mastitis cases can help to ensure that cows get the treatment that they need and when they need it as well as seeing to it that the farm milk market is protected. If a cow is sick enough to be treated and hospitalized, does the treatment area actually help the animal to recuperate or does it add to her misery? This veterinarian has seen many treatment areas and hospital pens that in all probability have made the cow sicker rather than better. Does your pen have good cow comfort, good and functional treatment facilities, good footing, feed and water? These are simple basics that are all too often overlooked in the daily hurry to get the other chores done. It is important to remember that certain types of mastitis will respond well to lactation therapy and a few will respond to dry cow therapy but none will respond in all circumstances. Treatment choices will depend on the producers experiences as to the past effectiveness of the drug for the type of symptoms exhibited, the availability of the product, withdrawal times, and the ability to ensure residue avoidance. Supplemental treatments may help further speed along favorable response. Such products may include calcium to reduce the hypocalcemic (milk fever) symptoms that are sometimes produced with certain gram negative infections. Products to reduce shock such as corticosteroids or nonsteroidal anti-inflammatory drugs, i.e. Banamine or aspirin. Supplemental fluids both IV and orally to deal with shock and dehydration. Systemic antibiotics, keeping in mind that many of these products do not cross from the blood into the milk in high enough concentrations to be effective in destroying or inhibiting the bacteria that are causing the infection. They may however help to prevent other bacteria from establishing themselves in other organ systems resulting in concurrent diseases establishing themselves. It is important to note that cows are most prone to mastitis infections during the two weeks after dry off and for the period two weeks before calving and two weeks after calving. The immune system of the cow at calving is at the lowest effective level that it will be during her entire lactation, thus it is of paramount importance that her exposure to conditions and pathogenic bacteria that can cause infections be minimized because it simply takes less for them to establish an infection. There is no magic antibiotic for the treatment of mastitis. Even if there were one, it would eventually select for bacteria that would be resistant to it and thus lose its potency. The more an antibiotic is used, the greater the probability that it will lose its effectiveness.

This paper has not dealt with the issues of biosecurity where there has been introduced active disease process into a herd through replacement animals or expansions. Suffice it to say that introduction of new animals to a herd may present significant disease threats, including mastitis. Every farm should work with their veterinarian and health advisory team to develop meaningful and effective strategies for these circumstances. It is beyond the scope and purpose of this paper to delineate such measures.