Old ideas vs. current realities in mastitis treatment decisions -

Historically high cull cow values, along with increased scrutiny for residues in milk and meat, should have already advanced your decision process for mastitis treatment by now. A valid veterinary-client-patient-relationship requires that every dairy owner and manager regularly reviews all of the treatment protocols with their attending veterinarian and includes plans to decide which cases are worth treating.

Roger S. Thomson

Nowhere is this more important than in the parlor, where the vast majority of antibiotics are used on the typical dairy. The days of treating every chip, every flake, every garget and even every watery quarter without a plan are gone.

This article will discuss the topic of mastitis treatment decisions in two parts. Part 1 will be “Keys to mastitis prevention” and Part 2 will be “Keys to best practice treatment decisions.”

Part 1: Keys to mastitis prevention

An ounce of prevention is worth a ton of cures in the current dairy economy. Everything possible must be done to reduce the number of bacteria on your cows’ teat ends before, during and after milking.

Research at Cornell using molecular profiling of bacteria has produced some new truths about some old beliefs. For decades, we have believed there are two basic categories of mastitis-causing bacteria:

• Contagious – bacteria that primarily live in the cow’s mammary gland and spread from cow to cow by contaminating the inside of a milking liner or milker’s hands

• Environmental – bacteria that primarily live in the cow’s environment and colonize the cow’s teat end when she lays down or gets dirty while outside the parlor.

The new truth is that bacteria cannot read and some strains of contagious bacteria do not spread from cow to cow in the parlor with any significant speed. And some strains of environmental bacteria can spread from cow to cow in the parlor like a wildfire.

So what we must focus on nowadays is to prevent both contagious and environmental spread of bacteria on every dairy, every day. The fundamentals to accomplish these tasks have been proven by decades of research and are as follows:

Contagious mastitis prevention

1. Post-dip every teat after every milking with an effective product that has been National Mastitis Council (NMC) protocol tested.

- The critical reason for this step is to kill as many bacteria as possible that spread to the cow’s teat during milking.

- At least three-quarters of the entire teat must be covered with post-dip to accomplish the above goals.

2 . Dry treat every quarter of every cow.

- This will help cure chronic and subclinical infections that can spread to non-infected cows during the next lactation.

- It is difficult to identify all infected cows at dry-off by using cost-effective methods (e.g., CMT, DHI-SCC, culture).

- Since up to 50 percent of new infections start during the dry period, this is a critical step to prevent new infections.

Environmental mastitis prevention

1. Pre-dip every teat with an effective product that has been NMC protocol tested.

- Full strength pre-dip kills the most bacteria; dipping then stripping, foaming and cups with brushes reduce the amount of germicide available to kill bacteria.

- Know the “speed of kill” for the germicide in your pre-dip for maximum results.

- Formulation matters, so ask for research from your pre-dip supplier to confirm the effectiveness of their product.

2. Use a towel to dry the teat and remove as many living bacteria as possible.

- The goal is to attach the milking unit to a clean, dry, well-stimulated teat.

- Routinely culture reusable towels to guarantee their cleanliness.

- Provide milker training frequently for maximum results – be a coach, not a boss.

3. Power prep brushes and robotic milkers require careful monitoring.

- They must clean all teats all of the time.

- The germicide and sanitizer used must produce a robust kill of bacteria on the teat and on the brushes.

Part 2: Keys to best practice treatment decisions

The goals for best practice treatment decisions are simple: Pick your fights carefully and when treatment is indicated, administer the drugs based on sound pharmacologic principles.

The two most common mistakes that result in unnecessary use of antibiotics (or other drugs) to treat mastitis are treatment of chronic mastitis cases that will not respond to therapy because of abscess and scar tissue formation, and trying to treat cows infected with bacteria or other microbes that will not respond to antibiotics.

Records are essential to identify previously treated cows and ensure that these cows do not enter the drug “merry-go-round.”

Additionally, records are critical to ensure that milk from treated cows does not enter the market and that treated cows are not culled for beef before drug residues are cleared.

Culture of milk from mastitis cases is a practical means of identifying typical mastitis-causing bacteria, whether done on the farm or at a vet clinic.

This information can be invaluable for herd-level decisions regarding milking routines, bedding, vaccination programs, etc.

Depending on the farm, this may not be practical to do on every mastitis case. In particular, milk samples should be collected from previously treated cows to ensure that further use of drug therapy is well-targeted to the causative pathogen or that the pathogen is even susceptible to antibiotics.

For example, treatment of Prototheca – an algae, not a bacteria – with antibiotics would be a waste of time, money and labor.

Mastitis therapy protocols, developed in conjunction with a veterinarian, are the foundation of any decision to treat a mastitis case. Protocols are only useful if everyone on the farm complies.

In the case of farms where employees are part of the treatment team, frequent training and review of the protocols, as well as proper administration, must be included.

If the protocol states that mastitis cows are not to be treated after two rounds of therapy, then everyone on the farm has to buy into this plan.

If the protocol states that teat ends must be completely cleaned with alcohol before infusion, then this needs to be monitored and reviewed regularly.

Human nature is such that drift from prescribed protocols is common. This is where your veterinarian, as the “science officer” for the herd, can help review and train farm personnel – and re-train, and re-train, etc.

Would a good basketball coach demonstrate to his players good positioning for a rebound just once on the first day of practice and then not drill or practice this technique for the rest of the entire season?

Would a winning coach expect players to perform their part in an offensive play without understanding why they are doing it?

Just like in basketball, we shouldn’t expect optimum performance from our employee team if herd managers aren’t winning coaches. This applies to all aspects of a herd quality milk program, including therapeutic protocols. PD

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