Fine-Tuning Mastitis Control Programs
Ken E. Leslie
Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada N1G 2W1
Take Home Messages
Improvement in udder health has been a major initiative of the dairy industry for over 40 years. The thrust of these efforts has been on the implementation and use of management techniques to limit the spread of major mastitis pathogens (11). Detailed mastitis control strategies have been outlined and promoted by the National Institute for Research in Dairying (NIRD) and by the National Mastitis Council (NMC). With proper implementation, these programs result in a dramatic decrease in the prevalence of common contagious mastitis pathogens (5,14). Herds that have successfully implemented a comprehensive mastitis control program also need to develop strategies to control infection with environmental organisms, as well as utilize an effective monitoring system for new infections (11). Achievement of excellent udder health for the production of high quality milk is a realistic and important goal for all aspects of the dairy industry.
In order to be effective, a mastitis control program must be adopted through an awareness of the status of udder health in the herd. Awareness can be heightened by milk price premiums based on milk quality, and/or penalty programs for high somatic cell counts (SCC) in bulk milk. Good diagnostic systems for the assessment of udder health status of individual cows, and herds, must be available. With an awareness created, and a system of managing the data to monitor udder health status in place, a cost-effective, adaptable and successful mastitis control program can be developed.
Principles of Udder Health Management
The success of an udder health program in an individual herd will depend upon its ability to fulfill three overall principles of udder health management (1). The specific steps of a program must be designed to fulfill these basic principle's which are as follows:
Elimination of Existing Infections.The control program must attempt to eliminate prevalent infections by reducing the duration of mastitis in the currently infected cows. Antibiotic treatment during the dry period is one of the commonly recommended methods of achieving this objective.
Prevention of New Infections.Mastitis control programs should reduce the rate at which new infections occur. For example, ensuring that all teats are clean and dry prior to machine attachment, as well as making certain that the milking machine is functioning properly are highly recommended procedures for reducing the new infection rate. However, the specific recommendations for reducing new infections will greatly depend upon the most predominant type of infection in the herd.
Monitoring Udder Health Status.An ongoing program to collect and manage udder health data from individual cows, and from the whole herd, is essential to evaluate the success of the mastitis control efforts. Monitoring is crucial to determine when changes are needed in the control program. The monitoring methods should also assist with specific decision-making, such as with therapy or culling. Although actively promoted by veterinarians and Dairy Herd Improvement agencies, monitoring has not been one of the points emphasized in the recommendations from organizations such as NMC. However, as milk quality premiums, and penalty programs become more and more meaningful, the need to use a continuous method of monitoring udder health will increase.
One version of a mastitis control program that can effectively and efficiently achieve each of these three principles of udder health management includes ten distinct steps (11).
Ten Steps For An Effective Mastitis Control Program
Each of these steps includes several details (Figure 1). However, it must be emphasized that the details within each of these steps are constantly being refined with the results of current research efforts. In fact, each of the 10 steps has experienced at least one significant advance in the last two years. It must also be emphasized that the specific points within each step, that are the most meaningful to the mastitis control program on an individual farm, may vary greatly between farms. Thus, advisors on the udder health management program of a farm should continually re-assess the impact of specific steps on the effectiveness of the program for that farm.
The objective of this paper is to briefly describe some of the most notable recent innovations in each of the steps for mastitis control. Several of these advances may develop into long-term meaningful changes in the way that veterinarians and dairy producers approach the control of mastitis in their herds. Other developments may only result in minor changes in the overall scheme of mastitis control. These innovations will be listed under each step of the recommended mastitis control program (Figure 1).
Proper Maintenance and Use of Milking Equipment
Appropriate design and function of milking equipment are clearly important features of mastitis control programs (3). Milking equipment manufacturers have made great advances in both the design and function of their equipment. The impact of equipment on rates of new intramammary infection has been reviewed (15). Significant advances continue to be made in our understanding of the interactions between milking machines and mastitis. Some of the most important advances are:
Employ Proper Milking Procedures
Appropriate milking management is critical for the control of both contagious and environmental mastitis. There are a great many differences and controversies with respect to the specific milking management recommendations made throughout the world (1).
Effective Dry Cow Management
Dry cow therapy of all quarters of all cows has been an integral recommendation for mastitis control program over the past 25 years (4,11). Use of an effective long-acting antibiotic preparation has been important in the reduction of bulk milk SCC through the control of contagious mastitis pathogens. Many herds have achieved very low herd SCC levels. Thus, the prevalence of existing infections is significantly reduced. Now, some herd managers are interested in the implementation of selective dry cow therapy programs. However, more effective methods are needed to detect cows that are entering the dry period with one or more quarters infected. In addition, methods to predict which cows are susceptible to new intramammary infections in the early dry period are needed.
Appropriate Treatment of Clinical Mastitis DuringLactation
Recently, dairy producers have adopted widely different protocols for the therapy of clinical mastitis during lactation. Some producers have elected to avoid therapy with intramammary antibiotics at all. Others have continued with aggressive antimicrobial therapy of mild clinical cases, even acknowledging that coliform infections may not need treatment. There would appear to be a substantial need for the development of a therapy protocol that would allow for the selection of cases which are most appropriate for antibiotic therapy.
Culling and Biosecurity for Contagious Pathogens
Elimination of chronically infected cows (with infections such as S. aureus or Mycoplasma) is an important aspect of decreasing the risk of exposure to these pathogens. However; this action will not result in long-term changes in udder health status of the herd unless there are improvements in the other aspects of mastitis control. In addition, the economics of extensive rapid culling needs to be carefully considered (11).
In supply managed milk marketing systems, replacements need to be added to the herd to meet the quota production requirements. Whether these animals are resident replacement heifers, or purchased herd additions, they represent a dilemma for biosecurity with respect to numerous disease problems. With rapidly expanding herd sizes, particularly in the United States, there is an increased need for concern about the introduction of contagious intramammary pathogens.
Good Record Keeping
One of the most difficult aspects of udder health management has been the development and implementation of workable record systems for clinical cases. Without an accurate record of the case and therapy information, it is difficult to monitor the incidence rates of environmental infections.
Maintain A Clean Environment
There is now a great deal of evidence that the implementation of standard mastitis control procedures will result in reducing bulk milk SCC (11). However, there is no guarantee that there will also be a low rate of clinical mastitis caused by environmental pathogens. In fact, some evidence exists that an increase in clinical cases by coliform agents may result (9). It is clear that dairy producers need to be more aware of the impact of environmental management on new intramammary infections (11). Some of the issues that are of particular importance are as follows:
Monitor Udder Health Status Regularly
The monitoring of udder health status is an important principle of udder health management that was overlooked in early programs. With both bulk milk and individual cow SCC information, as well as clinical mastitis data, it is possible to develop an on-going monitoring system for udder health.
Periodic Review of Mastitis Control Program
It is imperative that udder health advisors develop a regular method of periodic systematic evaluation of the mastitis control program. Without this periodic review, it is difficult to recognize and communicate that subtle changes may be needed in the mastitis control program of a particular farm.
Making progress with the udder health of a dairy herd can be positively influenced by implementation of the health management cycle (Figure 2). This process represents a cycle activity which involves setting of farm goals for udder health status. It is fortunate that objective, useable mastitis data is readily available. Bulk milk quality information, individual cow SCC data, and clinical mastitis case incidence rates are all easily retrieved. Thus, on-going monitoring of herd performance is quite feasible (11). From these data, decisions can be made and control programs implemented (1,11). It is important to acknowledge the lag-time and variability in a particular index of udder health, in order to set a realistic horizon for improvement.
With the use of this 10 step approach to udder health management, and by an on-going process of fine-tuning the mastitis control program, production of high quality milk should be achievable on all dairy farms.
1. Proper Maintenance and Use of Milking Equipment
•Service, maintain, and regularly evaluate equipment function according to manufacturer's guidelines.
•Ensure milking system is adequately sized to handle milk and air flow.
•For synthetic rubber inflations, replace after every 1000 to 1200 milkings.
•Thoroughly wash equipment after each milking.
•Sanitize equipment prior to each milking.
2. Employ Proper Milking Procedures
•Use a warm water, sanitizing solution to wash each cow's teats for at least 30 seconds.
•Dry teats immediately following washing.
•Use single-service paper towels for each step.
•Examine foremilk in a strip-cup for abnormalities.
•In situations of a high incidence of environmental mastitis, pre-milking teat disinfection may be useful.
•Attach teat cups within 60 seconds of udder prep.
•Adjust milker during milking to prevent liner slips.
•Shut-off vacuum to the claw before removing cluster; keep machine stripping to a minimum.
•Teat dip immediately following teat cup removal.
•Milk known problem cows separately.
3. Effective Dry Cow Managment
•Reduce milk production to below 25 lb per day before drying off.
•Dry cows off abruptly and dry treat each quarter immediately following the last milking.
•Dip teats, scrub the teat-end with an alcohol swab, and use the partial insertion method of infusion.
•Treat all quarters of all cows with an approved long-acting dry-cow antibiotic product.
•Teat dip immediately following dry cow therapy.
•Teat dip for one (1) week after drying-off, and prior to calving, with a barrier product.
•Ensure that dry cow nutritional and environmental management are appropriate.
4. Appropriate Treatment of Clinical Mastitis During Lactation
•Carefully consider economics of therapy decisions.
•Collect a pre-treatment sample for culture.
•Use an appropriate therapeutic regimen; as recommended by your veterinarian.
•Prior to infusion, disinfect the teat with germicide and scrub the teat-end with an alcohol swab.
•Use the partial insertion method of infusion.
•Single-dose syringes are recommended.
•Do not treat chronic non-responsive infections.
•Observe the correct withdrawal period for the product used, as stated on the label.
•Always follow recommended storage guidelines and observe expiry dates.
5. Cull Chronically Infected Cows and Maintain Biosecurity for Contagious Pathogens
•Cull cows with a persistently high SCC (i.e. greater than 500,000 over an extended period).
•Cull cows persistently infected with Staphylococcus aureus or other chronic infections (mycoplasma, nocardia, pseudomonas, or Actinomyces pyogenes).
•If available, request to see individual cow SCC data prior to purchasing a new cow (or use CMT).
•Isolate purchased cows and milk separately, until there is assurance of the absence of mastitis intramammary infection.
6. Good Record Keeping
•Conduct the cow-side California Mastitis Test (CMT) on suspect cows, and keep a record of results.
•Record cow, quarter and therapy used for the monitoring of clinical mastitis.
7. Maintain A Clean Environment
•Ensure stalls are of adequate size and design.
•Diligent maintenance of clean dry bedding.
•Ensure ventilation system is functioning properly.
•Remove manure regularly from stalls and yards.
•Ensure proper stocking density in facilities.
•Eliminate neutral-to-earth (stray) voltage.
8. Monitor Udder Health Status Regularly
•Enroll on the DHI individual cow SCC program.
•Examine rates and distributions of high SCC cows.
•Culture clinical cases and high SCC cows.
•Use CMT as a cow-side montior.
•Monitor herd udder health using reports from the regional regulatory agency or marketing organization.
•Calculate clinical mastitis rates and distributions on a regular basis. Monitor response to therapy.
9. Periodic Review of Mastitis Control Program
•Obtain objective evaluations from veterinarian, industry field person or extension representative.
•Use a step by step approach to the review.
10. Set Goals For Udder Health Status
10. Set Goals For Udder Health Status
•Set realistic herd targets for average SCC, average Linear Score and clinical mastitis rates.
•Prioritize management changes to achieve goals.
Farm: Veterinarian: Date:
Monitor and Assess Current Status
(Time Period: )
Goals or Standards
Performance Outcome Make Decisions
(Time Period ) Take Action
Monitor Farm Performance
Effects of Others Factors
By: K.E. Leslie, Ontario Veterinary College,
Dairy Health Management Certificate Program, 1991