MASTITIS IN THE AUSTRALIAN DAIRY INDUSTRY Insert presentation date here

TABLE OF CONTENTS 1. ABOUT MASTITIS 2. A SURVEY OF MASTITIS PATHOGENS IN THE SOUTH EASTERN AUSTRALIAN DAIRY INDUSTRY 3. CLINICAL MASTITIS 4. SUBCLINICAL MASTITIS 5. ANTIBIOTIC SENSITIVITIES 6. CONCLUSION

ABOUT MASTITIS

WHAT IS MASTITIS? MASTITIS IS THE INFLAMMATION OF THE COW’S MAMMARY GLAND, USUALLY CAUSED BY BACTERIA ENTERING THE TEAT CANAL AND MOVING TO THE UDDER. THE TWO MAIN TYPES OF MASTITIS ARE CONTAGIOUS AND ENVIRONMENTAL MASTITIS. Contagious mastitis Environmental mastitis Habitat Inside udders or on teat skin The cow's environment (e.g. manure, soil) How is it spread Contamination from infected milk Contamination from infected environment; can be introduced with intramammary tubes if teat ends are not sterile when treatment occurs. When is it spread Milking time Mainly at drying-off and around calving time; most cases seen at calving or early lactation. Bacteria Commonly Staph aureus and Strep agalactiae Commonly Strep uberis, E.coli, coliforms, Pseudomonas. Many others occur occasionally.* * Source: Countdown Downunder

SUBCLINICAL VS CLINICAL MASTITIS SUBCLINICAL MASTITIS Cow – no observable changes Udder – no observable changes Milk – no observable changes but significant differences in milk composition CLINICAL MASTITIS (CHRONIC, MILD, ACUTE, SEVERE) Cow – spectrum from extremely unwell to no observable changes Udder – spectrum from hot, swollen and painful to no abnormalities Milk – displaying abnormalities from discolouration, clots, blood, clots, flakes, wateriness

IMPORTANCE OF MASTITIS CONTROL Countdown Downunder has shown that every four clinical cases of mastitis cost around $1,000 These losses occur through: Lower production Lower payments for milk due to quality Increased costs of treatment and culling

CELL COUNTS IN MILK BULK MILK CELL COUNT (BMCC) SHOWS THE CONCENTRATION OF COW BODY CELLS IN VAT MILK. BMCC is an Indirect measure of subclinical mastitis in the whole herd BMCC can provide a guide of infection levels in a herd Each 100,000 cells/mL indicates about 10% of cows are infected Guidelines Below 150,000 cells/mL Excellent mastitis cell count control 150,000 – 250,000 cells/mL Good control. Meets level for premium payment with most dairy companies 250,000 – 400,000 cells/mL Moderate mastitis control and cell count control Above 400,000 cells/mL Poor / inadequate control. Milk not considered fit for human consumption * Source: Countdown Downunder

MASTITIS TREATMENT ANTIBIOTIC DRY COW TREATMENT Dry cow treatment is used to treat existing infections and reduce the number of new infections that may occur during the dry period The most appropriate dry cow treatment strategy should be planned with a veterinarian The choice of treatment will depend on a number of factors, including the spectrum of activity, cure rates and how long the cow has been infected TEAT SEALANTS Teatseal is a non-antibiotic substance which creates a physical barrier in the teat canal to prevent new intramammary infections during the dry period and reduce the incidence of clinical mastitis in early lactation Teatseal used in combination with an intramammary dry cow antibiotic has been shown to be more effective than an intramammary antibiotic alone, reducing the rate of clinical mastitis by up to 70%

INTERNATIONAL CONTEXT THE AUSTRALIAN DAIRY INDUSTRY IS RECOGNISED FOR ITS RESPONSIBLE USE OF ANTIBIOTIC TREATMENTS Internationally, the responsible use of antibiotics to treat mastitis has proven to be a greater challenge After European policy makers expressed concern over the link between antibiotic use in livestock and antibiotic resistance in humans, the Netherlands took its own stance and, in 2012, introduced penalties for failing to reduce on-farm antibiotic use including: Targeting 50% reduction in use New farm protocols in place, aimed at prevention Antibiotics used primarily for treatment rather than prophylactically

JUDICIOUS USE JUDICIOUS USE IS IMPORTANT TO MINIMISE THE DEVELOPMENT OF RESISTANCE WHILE MAINTAINING EFFECTIVENESS TO PREVENT DISEASES Requires an understanding of pathogens involved Need to assess any changes in antimicrobial sensitivities over time

A Survey of Mastitis Pathogens in the South Eastern Australian Dairy Industry

WHY CONDUCT A MASTITIS SURVEY IN AUSTRALIA? Farmers often make the comment “We need new antibiotics to treat mastitis because the bacteria are resistant to the ones we currently have” Farmers often ask the question “Do I need different antibiotics for different stages of lactation, different ages or different regions?” Farmers will also question their vet “Is this type of bacteria the standard cause of mastitis in Australia or is something different happening on my farm?

SURVEY OBJECTIVES Determine the prevalence of clinical and subclinical mastitis pathogens in key dairy producing regions Investigate the impact that seasons, stage of lactation and lactation number have on mastitis pathogen prevalence Identify the current antibiotic sensitivity patterns for Australia’s most costly pathogens in dairy cattle Understand the relevance of currently available treatment options used in clinical and subclinical mastitis therapy 1 2 3 4

ABOUT THE SURVEY SURVEY SAMPLES Australia’s largest study into the prevalence of mastitis pathogens in local milk producing regions, including: 13 veterinary practices 65 farms 2986 clinical mastitis samples over 13 months 1038 subclinical mastitis samples All positive cultures submitted for culture and sensitivity (CLSI approved standards) All positive cultures archived SURVEY DESIGN Herd size: > 464 (210-1000) cows in milking herd Mean BMCC in previous year of 100,000-500,000 Herd testing on regular basis (minimum four tests per year) and maintain electronic herd health recording system Met acceptable animal welfare standards Project fully funded by Zoetis in 2010 Collaborated with Dairy Focus to run the survey throughout 2011 and early 2012

CLINICAL MASTITIS

OVERALL CLINICAL MASTITIS CULTURE RESULTS % of pathogens isolated

OVERALL CLINICAL MASTITIS CULTURE RESULTS OVERALL, 39.3% OF SAMPLES WERE EITHER CONTAMINATED (16.1%) OR PRODUCED NO GROWTH (23.2%) With the contaminated and no growth samples excluded the major pathogens are: 54.3% Strep. uberis 14.8% Staph. aureus 11.7% E. coli 8.9% Strep. dysgalactiae Total - 89.7%

WHAT DO THESE RESULTS MEAN AT THE FARM LEVEL? One in six samples were contaminated at the time of collection Farmers were trained and supplied with all consumables required to collect samples aseptically If contaminating bacteria are still present on the teat orifice at the time of collection - they would still be present at the time the antibiotic treatment was infused If a cow is treated with three tubes of intramammary antibiotics per case of mastitis, she will have a 50% chance of receiving a new infection due to poor hygiene! Important to treat the existing infection and not to introduce a new infection

WHAT DO THESE RESULTS MEAN AT THE FARM LEVEL? 54.3% Strep. uberis – environmental contaminant 14.8% Staph. aureus – cow associated bacteria 11.7% E. coli – environmental contaminant 8.9% Strep. dysgalactiae – cow associated bacteria The big four bacteria cause the majority of mastitis – no new super bacteria have emerged Environmental bacteria have taken over from cow-associated bacteria as the leading cause of mastitis

CLINICAL MASTITIS Stage of lactatioN

CLINICAL MASTITIS VS STAGE OF LACTATION MAJOR PATHOGENS ISOLATED DURING LACTATION OUTCOMES The stage of lactation appears to have little impact on the frequency of the major bacteria Strep. uberis was the dominant pathogen at all stages of lactation and was consistently isolated at a rate greater than 30%

CLINICAL MASTITIS GEOGRAPHICAL REGION

CLINICAL MASTITIS VS GEOGRAPHICAL REGION MAJOR PATHOGENS ISOLATED BY REGION

CLINICAL MASTITIS VS GEOGRAPHICAL REGION MINOR PATHOGENS ISOLATED BY REGION

CLINICAL MASTITIS VS GEOGRAPHICAL REGION Regional differences were minor Western District of Victoria recorded the highest incidence of Strep. uberis at 36.8%, Gippsland recorded lowest at 27.5% Except Staph. aureus was recorded at 12.7% of cultures from Gippsland, but only 4.5% of cultures from Northern Victoria E. coli was the second most likely pathogen in samples from Northern Victoria at an isolation rate of 9.7% C. bovis was isolated at a rate of around 1.5% for the mainland states, yet only a single isolate in Tasmania

CLINICAL MASTITIS NUMBER OF LACTATIONS

CLINICAL MASTITIS VS NUMBER OF LACTATIONS MAJOR PATHOGENS ISOLATED BY LACTATION NUMBER OUTCOMES Heifers produced the highest rate of Strep. uberis infections; to manage this: Maintain a clean environment for calving Introduce a teat sealant Cows had broadly similar rates of infection with the major bacteria regardless of their age – similar treatment strategies will apply to all age groups

SUBCLINICAL MASTITIS

SUBCLINICAL MASTITIS RESULTS SUBCLINICAL MASTITIS PATHOGENS ISOLATED IMPORTANT FINDINGS On a single occasion on some of the enrolled farms, a further 20-30 samples were collected from a selected group of cows that displayed a high somatic cell count in mid-to-late lactation No growth result for the subclinical mastitis samples (17.4%) was broadly similar to the rate calculated for the clinical mastitis samples (23.2%) The frequency with which a contaminated sample was submitted from cows with subclinical mastitis (40.7%) was far higher than for clinical mastitis submissions (16.1%)

CONTAMINATED SAMPLES - IMPLICATIONS WHY DO WE SEE HIGHER RATES OF CONTAMINATION WHEN COLLECTING A COMPOSITE SAMPLE FROM FOUR QUARTERS? The sterility of the four collectors is not maintained Sampling 20-30 cows rather than a single cow The sampling is conducted at the end of milking when more manure is present in the environment Sampling is seen as just ‘another job’ at the end of the milking session – a time when attention to detail may not be a priority These cows will receive DCT shortly after this sampling procedure (antibiotics +/- teat sealant) The antibiotics commonly used will not necessarily cure the environmental bacteria that may be infused into the udder if hygiene is poor Significant time and money is invested in applying DCT - the ROI is dependent on strict hygiene

SUBCLINICAL MASTITIS RESULTS SUBCLINICAL MASTITIS MAJOR BACTERIA IMPORTANT FINDINGS Staph. aureus was the organism most frequently isolated from subclinical mastitis samples (17.5%) Strep. uberis returned 141 positive cultures (13.1%) E. coli was only cultured on 10 occasions (0.9%) from the samples submitted from high ICCC cows Regional differences were minor; Staphs and Streps were the predominant organisms likely to be present in a high ICCC cow at the time of drying off Data excludes no growth and contaminated samples

ANTIBIOTIC SENSITIVITIES

CLINICAL MASTITIS SAMPLES STREP UBERIS

CLINICAL MASTITIS SAMPLES STAPH AUREUS

CLINICAL MASTITIS SAMPLES E COLI

CLINICAL MASTITIS SAMPLES STREP DYSGALACTIAE

SUBCLINICAL MASTITIS SAMPLES STAPH AUREUS

SUBCLINICAL MASTITIS SAMPLES STREP UBERIS

SUBCLINICAL MASTITIS SAMPLES STREP DYSGALACTIAE

SUBCLINICAL MASTITIS SAMPLES CLOXACILLIN SENSITIVITY

CONCLUSION

SUMMARY A RESULT THE DAIRY INDUSTRY CAN BE PROUD OF Cloxacillin has been the most commonly used antibiotic in Australia for treating mastitis over a 35 year period The Staphs and Streps responsible for the clinical cases of mastitis in this survey were all still 100% sensitive to this antibiotic – a remarkable result given the time this antibiotic has been used Australian vets and producers can confidently say they have been using antibiotics responsibly

THE FUTURE THE BACTERIA CAUSING MASTITIS IN OUR HERD IN 2013 ARE STILL HIGHLY SENSITIVE TO THE ANTIBIOTICS WE CURRENTLY HAVE REGISTERED IN AUSTRALIA Producers may need to take more care in the application of these antibiotics to improve cure rates – focus on hygiene, administration technique and ensure 100% compliance with full course of treatment The industry may need to investigate new ways of using existing antibiotics to achieve higher cure rates, for example: Extended treatment strategies Different formulations Earlier detection of clinical mastitis and prompt treatment strategies may also enhance the effectiveness of the antibiotic arsenal