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A fresh look at the five-point mastitis control plan

Rick Watters for Progressive Dairyman Published on 18 January 2018

There have been many different programs developed over the years targeting improved udder health and the production of high-quality milk. Some of the programs have been around for a while and others, which had soft funding sources (e.g., state budgets), have come and gone.

One mastitis control program developed in the United Kingdom during the 1960s by the National Institute for Research into Dairying (NIRD) is called “The Five-Point Mastitis Control Plan,” and it is still followed today. The five-point plan was developed with the intention of reducing both clinical and subclinical mastitis through the control of contagious mastitis-causing organisms.

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“Mastitis and Milk Quality: The Five-Point Mastitis Control Plan Revisited” is the theme of the 57th annual meeting of the National Mastitis Council (NMC), Jan. 30 – Feb. 2, in Tucson, Arizona. So we thought it would be good to refresh everyone’s memory as to what is included in the five-point plan. The five points are as follows:

  1. Treat and record clinical cases
  2. Post-milking teat disinfection
  3. Dry cow therapy
  4. Cull chronic cases
  5. Milk machine maintenance

Depending on the type of mastitis-causing organisms (contagious versus environmental), it is plausible environmental mastitis may be a larger concern than contagious mastitis on many present-day dairy farms. When we analyze the aerobic sample results from Quality Milk Production Services for 2016, it indicates that for quarter samples (clinical mastitis or high-somatic-cell-count quarters) the top five mastitis-causing organisms identified are environmental.

However, when we analyze the composite (fresh cow screening) sample results, Staph aureus is the second-most-common organism identified. This leads one to ask: How does The Five-Point Mastitis Control Plan work today in controlling mastitis? We will take a look and see how each of the five points works today.

1. Treat and record clinical cases of mastitis

The 2014 National Animal Health Monitoring System (NAHMS) report indicated 46.5 percent of farms use some sort of electronic record-keeping program, and 98 percent of farms with more than 500 cows use an electronic record-keeping program. That means 83 percent of cows in the U.S. are documented through electronic record-keeping programs.

Digging deeper, 72.5 percent of farms use a record-keeping system to document mastitis, and 94.5 percent of farms with 500 or more cows record mastitis events. Additionally, approximately 97 percent of cows with clinical mastitis are treated with an antimicrobial, with 89.4 percent treated with an intramammary antimicrobial when mastitis is identified.

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Treatment of clinical mastitis has taken on a new approach recently, with more farms following a pathogen-based treatment protocol. This brings up two points: First, treat the mastitis organism and not the signs. Second, develop treatment protocols.

Pathogen-based treatment requires collecting a milk sample from the clinical quarter and submitting it for identification. Based on the results, the cow is either treated or not treated 24 hours after the mastitis event is detected. Pathogen-based treatment means cows that are culture-negative are not treated, reducing the use of intramammary antibiotics by 30 to 40 percent.

About 45 percent of farms are using some sort of culturing program at the cow level, which indicates mastitis treatment decisions can be made at the pathogen level instead of following blanket treatment of all animals with mastitis. More dairy operations are developing protocols for the diagnosis and treatment of mastitis, with larger dairies having more on-farm protocols.

Treating and recording cases of clinical mastitis can be even more valuable with electronic records, development of protocols and the use of pathogen-based treatment.

2. Post-milking teat disinfection

Post-milking teat disinfection has always been associated with reducing the risk of contagious mastitis because, if applied properly, it provides protection against the mastitis-causing organisms in the milk residue left on the teat after milking.

Also, the disinfectant droplet at the teat end protects against invading mastitis organisms until the teat canal closes after milking, which can take 60 minutes or more. Overall, 98.6 percent of farms in the U.S. use a post-milking teat disinfectant.

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One often-overlooked aspect of post-milking teat disinfectants are the skin conditioning agents in the dip. Proper skin condition is key to reducing the risk of mastitis-causing organisms colonizing the skin of the teat. Skin condition is non-selective in that poor skin condition is a risk for both contagious and environmental mastitis.

Post-milking teat disinfection is just as important for controlling contagious mastitis as it is for controlling environmental mastitis.

3. Dry cow therapy

The dairy industry has followed the protocol of administering an intramammary antibiotic in each quarter at dry-off for years. Immediately after dry-off and just prior to calving are the two highest-risk periods for a cow to obtain a mammary infection, and blanket dry treatment has been used to cure infections and prevent new infections from occurring during the dry period.

Over 90 percent of cows are given an intramammary dry treatment at dry-off, according to the latest USDA NAHMS survey.

Recently, the idea of selective dry cow therapy has become more popular. The highest use of antibiotics on a dairy farm occurs at dry-off because each cow is administered four dry treatment tubes during the drying-off process. What if there was a way to reduce the use of antibiotics at dry-off and not increase the risk of obtaining an intramammary infection during the dry period?

The idea of identifying low-risk and high-risk cows for obtaining an intramammary infection during the period has been proposed. In brief, if a cow at dry-off has a low somatic cell count (SCC) at last test, a low SCC average for the last three test days and has only one case of mastitis during lactation, this cow may be a candidate for not receiving an intramammary antimicrobial at dry-off. The use of an internal or external teat sealant may still be prudent.

The future of dry cow therapy for all cows may become less important with improved dry cow management and the use of cow-level milk quality records.

4. Cull chronic cases

Chronic mastitis is a two-headed animal in that there is both chronic clinical and chronic subclinical mastitis. Both forms of chronic mastitis have very low cure/recovery rates. Chronic clinical mastitis is when the same mastitis-causing organism causes mastitis in the same quarter.

Subclinical chronic mastitis is when the test-day SCC is greater than 200,000 cells per milliliter at the current and previous test days.

It is advised that dairy producers who test cows for SCC focus on curing new infections to control or reduce chronic subclinical infections. It is also advised that cows with new and chronic infections have a milk sample collected and submitted for aerobic culture so you are able to manage the organism causing the new and chronic infections.

Based upon the culture results from a chronically infected cow, the producer may decide to cull the cow, cull the quarter or dry the cow off, depending on the cow’s stage of lactation and pregnancy status.

Culling chronic cows is advised when trying to prevent the spread of contagious organisms and when trying to lower the overall SCC; however, simply culling an animal from the herd will not solve your SCC issue. Culturing chronic cows is advised even if the animal will be culled from the herd. You must know what the mastitis-causing organism is in order to manage it.

5. Milk machine maintenance

If not properly maintained, milking machines can be a risk factor for causing machine-induced mastitis. In the past, it was believed milking machines and the milk routine only contributed to spreading contagious mastitis; however, we know this is not true. The milking machine, if not functioning properly, can put the cow at risk for both environmental and contagious mastitis.

There are three ways that a milking machine can increase the risk of causing mastitis. First, the milking machine can be the vector for transporting mastitis-causing organisms from one cow to the next (often referred to as contagious transmission).

Next, when the milking unit is left attached to the teats and there is no milk flow, this exposes the teats to high levels of vacuum and is referred to as overmilking.

Teats exposed to vacuum under conditions of no or low milk flow will see an increase in fluid at the end which, in the short term, leads to a longer period of time for the teat canal to close after milking. Long-term overmilking leads to hyperkeratosis.

Liner slips are the third way a milking machine could cause machine-induced mastitis. NMC has a set of guidelines for evaluating the vacuum and air flow of your milking system, and it is advised that the NMC vacuum and air flow test be completed annually on every milking system. These guidelines can quickly rule in or rule out the milking system as a risk for causing machine-induced mastitis.

Conclusion

The Five-Point Mastitis Control Plan is still relevant and can be managed to control mastitis. We can all agree there are other components we would like to add to the mastitis plan, such as the environment, milking routine, segregation of high-SCC cows and pre-dipping, to name a few.

However, if you follow the five points outlined above, you will have a good chance of reducing mastitis within your herd. Use of modern mastitis management and technologies along with the Five-Point Mastitis Control Plan will lead to improved udder health.  end mark

Rick Watters, Ph.D., is Western laboratory director and a senior extension associate with Quality Milk Production Services. Email Rick Watters

Quality Milk Production Services is a program of the animal health diagnostic center in the department of population medicine and diagnostic sciences within the College of Veterinary Medicine at Cornell University. It offers a variety of services, notably on-farm evaluations of management and equipment and whole-herd milk cultures, through its laboratories in Ithaca, Warsaw, Cobleskill and Canton, New York.

Rick Watters
  • Rick Watters

  • Western Laboratory Director and Sr. Extension Associat
  • Quality Milk Production Services
  • Email Rick Watters

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