What are the keys to controlling Strep uberis mastitis in dairy herds?

Transcription

1 Fat Sheet: Your Levy at Work What are the keys to ontrolling Strep uberis mastitis in dairy herds? The bateria Streptoous uberis (also known as Strep uberis) is a ommon ause of mastitis in dairy attle in many ountries around the world. Over the past two deades it has beome the leading ause of linial and sublinial mastitis in Australian and New Zealand dairy herds (J Malmo unpublished data 2010, MDougall 1998, Petrovski et al 2009). Strep uberis is passed in the faees of attle (and other ruminants) and an survive for up to 2 weeks in fresh dung or faeal-ontaminated mud or straw (Lopez-Benavides et al 2007). It is regarded as an environmental pathogen beause ows are likely to develop intramammary infetions if their udders are exposed to ontaminated material, espeially if they have damaged teat skin or open teat ends. The emergene of Strep uberis as a problem for pasturebased herds follows intensifiation of the Australian industry, with higher stoking rates inreasing ow exposure to environmental bateria. Typial hanges in farm systems that have inreased the risk of environmental infetion inlude widespread use of alving and feed pads, loafing areas and heavy traffi around water troughs, gateways and laneways. Higher yielding ows and those fed onentrate-based transition diets may also be more at risk. Many ows in the herd an beome infeted if exposed to environmental bateria at a vulnerable time: espeially in the fortnight after drying-off and the weeks either side of alving or in the hour immediately after milking. Inreasing trend in the proportion of Strep uberis isolates from milk ultures in the Maffra, Vitoria, region from 1997 to 2009 It is likely that faeal shedding by ows is needed to maintain Strep uberis in the environment. Strep uberis ontamination is ommon in laneways with medium to high traffi. Paddoks show a high degree of ontamination immediately after grazing but minimal ontamination before grazing. Typially pre-milking preparation in Australia and New Zealand does not involve washing and drying teats with an individual paper towel. This minimalist pre-milking routine probably ontributes to the inreasing prevalene of Strep uberis infetions. Aggregated data from multiple overseas studies has demonstrated more than 600 strains of Strep uberis ( Importantly Strep uberis an also spread from ow-to-ow at milking (Zadoks et al 2009). Most quarters that beome infeted have high ell ounts (often above 500,000 ells/ ml) that return to a normal ell ount within 2-3 weeks but a small perentage of ows remain hronially infeted and shed bateria in their milk (Hogan and Smith 1997). This allows the bateria to spread from ow-to-ow via the mehanisms assoiated with ontagious mastitis bateria. So despite its reputation as an environmental pathogen, ontrol of Strep uberis also requires attention to management praties that minimise milk droplet impats during milking, redue the number of bateria around the teat end and maintain healthy teats. There are a large number of strains of Strep uberis. In an Australian study, 62 different strains were found in 138 isolates from four herds, with between 10 and 26 different strains in eah herd (Phuektes et al 2001). Some strains are more able to adapt to speifi host tissues (survive in mammary epithelial ells for example) while the less host-adapted strains are rapidly eliminated by the ow s immune system (Tamilselvam et al 2006). The impliations of strain differenes on spread of infetion, treatment effiay and ontrol options are still unfolding. There is no effetive vaine on the horizon yet. Beause ows are likely to be regularly exposed to Strep uberis in the environment, mastitis management should aim to redue the likelihood of ows beoming infeted Page 1

2 rather than to eliminate the infetion from the herd. The fous of attention here is on having a dry ow strategy and drying-off proess that ensures that teat anals are sealed; a alving management plan that minimises exposure to ontamination; and milking management routines for putting teatups on lean, dry teats, and minimising exposure of suseptible ows to high traffi areas. Teat sealants provide an immediate seal to the teat anal at drying-off and are a highly effetive way of reduing the inidene of linial mastitis around the time of alving. They have been widely available in Australia sine 2003 for use in uninfeted (low ell ount) ows to protet them from infetion for the duration of the dry period. Reent experiene in Australia shows administration of antibioti Dry Cow Treatment AND teat sealant at drying-off provides signifiant further redutions in new infetion rates at alving (Runiman et al 2008). Although it is more expensive and a larger job (all quarters reeive two intramammary tubes) this pairing is now being used as a fundamental plank in the ontrol program for many herds with endemi Strep uberis problems. Farmers need to disuss treatment options and strategy with their veterinarian. To avoid problems with milk quality, it is important to instrut lients on how to use teat sealant its administration and evauation at alving. The Countdown Fat Sheet on Using teat sealants in your herd reinfores the key points. The main opportunity for the treatment and ure of Strep uberis infetions that have ourred during latation is through antibioti Dry Cow Treatments at dryingoff. The drug of hoie also needs to be disussed with the herd s veterinarian as longer-ating preparations are likely to be reommended. Treatment of linial ases during latation often removes linial symptoms although it may be diffiult to ahieve a bateriologial ure in some ases. A reent review (Zadoks 2007) examined the results from 17 field studies on treatment of linial and sublinial Strep uberis mastitis during latation. Experimental infetion studies were not inluded in this work. The field studies employed a wide range of antimirobials and treatment routes. The treatment duration varied from onventional treatments of 2-3 days to extended treatment periods of up to 8 days for sublinial infetions and longer for non-responsive linial ases. The bateriologial ure rates for linial ases with onventional treatments ranged from 50% to 90%. For untreated linial ases, the ure rate averaged 19%. Cure rates are likely to vary with the strain of Strep uberis ausing the infetion. Strep uberis infetions are normally suseptible to antimirobials suh as peniillins and ephalosporins. Marolide antibiotis (erythromyin, tylosin, tilmiosin) have the advantage of being able to penetrate intraellularly but Strep uberis often shows resistane to this drug family. After omparing different treatment regimens, Hillerton and Kliem (2002) reommended intramammary treatments not ombined with intramusular antibiotis, and that extended intramammary treatment ourses may be required. The Withholding Period for a registered antibioti treatment does not apply when the treatment ourse is extended or intramammary treatments are ombined with parenteral antibioti treatments. There is urrently no guide to what withholding period may be neessary. It may be worthwhile disussing sreening for antibioti residue with the fatory field offier. Given the relatively low ure rate it is important to remain vigilant for reurrene of linial ases of Strep uberis. In pratial terms, if a treatment regimen appears to be suessful on a farm (if no more than 2 linial ases in 10 require a seond ourse of treatment) it is worth stiking with that protool. Treatment reommendations for sublinial infetions during latation are even less ertain. Cure rates in high ell ount ows are even lower than linial ases (Zadoks 2007). Given the variable and possibly poor response to treatment the osteffetiveness of treatment of sublinial infetions during latation is questionable. In some irumstanes the only way to remove udder infetions is to ull persistently infeted ows: those that have had three or more linial ases in one latation OR ows that have had ell ounts above 250,000 ells/ml in two onseutive latations despite intervening antibioti Dry Cow Treatment. Researh priorities Researh into the benefits and pratiality of modifying pre-milking ow preparation praties in Australia and New Zealand to redue new infetion rates with Strep uberis and other environmental bateria is a HIGH priority. Little is known about the strains of Strep uberis found on Australian dairy farms. Strain typing of isolates from herds with high numbers of repeating linial ases may be worthwhile and is a MEDIUM priority. The effiay and ost-effetiveness of treatment of sublinial mastitis aused by Strep uberis during latation is not well enough understood. Further study of possible treatment options in latation is a MEDIUM priority. General approah to investigating a mastitis problem To solve a mastitis problem advisers must be onfident that they have learly defined the nature of the problem, determined the bateria involved and identified the fators on the farm that are likely to be ontributing to the problem. This usually requires oordinated input from several disiplines inluding veterinarians, milking mahine tehniians and, in the ase of Strep uberis mastitis, nutritionists. They an then help the farm team to build and implement a plan that will work. This general approah is shown in the flowhart below. Page 2

3 1. Desribe the presenting problem Desribe the problem as the farmer sees it Examine and interpret the available information and identify information gaps Make your preliminary definition of the problem Plan how to start gathering the next set of ritial information 2. Define the problem more speifially using milk ulture results Interat with a vet to determine what milk ultures are available. If adequate milk ulture results are not available, the vet should plan the detailed milk sampling strategy and organise sampling and transport of samples to the laboratory Interpret milk ultures to determine the bateria ausing the problem in the herd Consider the likely soures and modes of transmission of the bateria in the herd 3. Ativate your advisory team Identify who needs to be involved in this investigation With the advisory team, plan relevant examinations using the Investigation Master Sheet Do the tests and analyse the results 4. Collate and assess findings with the advisory team With the advisory team, ollate and assess the results using the Investigation Master Sheet Consider bouning ideas off an experiened mentor Identify further examinations, do them and assess the results Agree to the key fators ritial to resolving the problem (hek against presenting and re-defined problem) Report initial findings to the farm owner and disuss options for plan development 5. Develop a farm plan with the farm team Organise a farm meeting and involve the whole team in planning pratial ways of addressing the key areas needed to resolve the problem for this herd Summarise them on a report [e.g. Farm Mastitis Ation Plan] Ativate proesses, agree to triggers for ation and set a date for review 6. Review progress Measure progress in eah of the key areas and make a date to review overall progress Tehnote 13 (February 2003) ontains a Mastitis Investigation Pak to help the advisory team systematially ollet, ollate and prioritise information. See Desribe the presenting problem Strep uberis an ause high bulk milk ell ounts or linial ase problems in herds. All ows with linial mastitis aused by Strep uberis will (by definition) have hanges in their milk (wateriness or lots that persist for three or more squirts of milk) but only half of them will also have an enlarged, inflamed quarter. In about 10% of ases the ows develop a fever and go off their feed. The timing of the ourrene of linial ases an assist with problem definition. Intramammary infetion with environmental bateria usually ours in the first two weeks of the dry period or in the weeks around alving, espeially if there is teat end damage or oedema. Certain irumstanes during latation will predispose ows to infetion by environmental bateria. When onditions get wet, muddy and humid the risk of linial and sublinial mastitis greatly inreases, espeially if teats are not washed and dried before milking. Exposure to the bateria is higher and the teat skin and teat ends tend to be less healthy. Another time at whih ows may beome infeted is when intramammary treatments (antibioti treatments, teat sealants or other infusions) are administered without maintaining metiulous hygiene. In this situation speks of dirt on the tube or teat skin are fored through the teat orifie and teat anal into the udder. The following types of presenting problems ould be seen in herds with Strep uberis: Clinial mastitis in ows at alving or in the first 100 days of latation (even though ows may have been given antibioti Dry Cow Treatment). Clinial ases in first latation heifers before or after alving. High Individual Cow Cell Counts (greater than 250,000 ells/ml) in heifers or ows at the first or seond herd test after alving. Higher than expeted numbers of linial ases throughout the latation. A Bulk Milk Cell Count greater than 250,000 or trending up over a premium milk quality band threshold (not neessarily at the same time as linial ases of mastitis). Establishing the timing of new infetions and the rate at whih infetion is spreading an greatly failitate problem diagnosis. This an be done by generating a Countdown Mastitis Fous report through the loal herd reording organisation (or go to Clinial ase reords are a valuable aid to the diagnosis of Strep uberis problems in herds. As paperbased reords are rarely onverted to an effetive overview of the herd situation, farmers should be enouraged to enter ases on one of the ommerially available herd software pakages. This data an lead to a muh more informative Countdown Mastitis Fous report. Page 3

4 This example Mastitis Fous report inorporated herd test information with linial ase treatment and dry ow treatment reords from the on-farm herd management software. This report was generated in response to an inrease in new linial mastitis ases during and after the August and September alving period. The month by month analysis of linial ase rates (Your alving system box and Clinial mastitis box) indiates the timing and rate of new infetions. A total of 27 milk samples were olleted from linial ases during August and September. These frozen samples grew eight Strep uberis positive ultures from a total of 18 positive ulture results. Subsequent investigation revealed a hange in risk fators for new infetion from Strep uberis during the alving period on this farm. In the wet weather, traks had broken down and the feeding area had not been leaned. Page 4

5 Define the problem as Strep uberis As with any mastitis investigation, milk ulture results are required from a suffiient number of typially affeted ows to determine whether Strep uberis is the ause of the problem in the herd. Common sampling strategies inlude: Taking samples from every newly identified ase of linial mastitis (immediately before starting a ourse of treatment). Samples an be refrigerated and submitted to a laboratory within 48 hours OR frozen for up to 3-4 months (see Tehnote 4.3). The samples are immediately available for ulture should a problem start to esalate. Beause the perentage of nogrowth ultures appears to inrease markedly when samples are held frozen for longer than 1 month, PCR rapid sreening (see Moleular tests below) may be the preferred option for any samples held frozen for longer periods. Using herd reording results to identify sublinially infeted ows (ows with an Individual Cow Cell Count greater than 250,000 ells/ml). Countdown Tehnote 13 (setion C) indiates that it is important to have at least 20 effetive milk ulture results when onduting a herd mastitis investigation. Isolation of Strep uberis in around 25% or more of these samples indiates an inreased risk of udder infetions assoiated with this bateria. Moleular tests DNA tests for bovine mastitis pathogens are now ommerially available in Australia. These systems provide a rapid sreen for the presene of DNA from multiple bateria at a single test. The ompany that does the Bulk Milk Cell Count testing for most Australian herds is now offering a Pathoproof Polymerase Chain Reation sreening test to detet the presene of Strep uberis DNA in bulk milk samples. As with any vat test, are must be taken when interpreting the results. Moleular tests are highly sensitive and an detet very small numbers of bateria. The hallenge is to ensure that these bateria have ome from within the udder, not from teat skin, hands, dirt and faeal partiles or unwashed equipment. Follow-up sampling of suspet ows is strongly reommended after a sreening test. Beause Strep uberis is assoiated with ow faees in the environment it is important to ensure milk samples sent to the laboratory are taken from a stream of milk that has not touhed the teat skin or any other surfae. Fatsheet A of the Countdown Downunder Farm Guidelines for Mastitis Control provides a omprehensive desription of how to ollet milk samples aseptially. If there is any doubt about quality, have an experiened person ollet the samples. Tehnote 4.3 gives a detailed desription of sampling strategies and reasons for milk samples yielding no growth. The Vat milk tests FAQ sheet desribes some of the issues that need to be onsidered when testing bulk-tank milk sample. Ativate your advisory team Resolution of a Strep uberis issue is likely to involve the farm manager, veterinarian, milking mahine tehniian and milking staff at a minimum. Nutritionists also have an important role to play around the advie and support for management of the transition period. It is reommended that advisers use a team approah when identifying and prioritising ation around the key fators ontributing to the problem. This approah gives the best hane of suess as eah profession understands how their ontribution an progress the situation on farm. Collate and assess findings with the advisory team One Strep uberis has been onfirmed the job of the advisory team is to identify how and when ows are beoming infeted, espeially the soures of infetion and important risk fators, as these are ritial for ontrol. This is best done systematially to avoid oversights given the multifatorial and often omplex nature of herd mastitis problems. The aim of the investigation is for the team to agree to prioritise the key fators and disuss ontrol options with a farm owner. The People in Dairy resoures ontain useful information on planning the farm roles, responsibilities and workplan. See the Working Together Live Library setion of the website (www. thepeopleindairy.org.au) Develop a farm plan to ontrol Strep uberis Control programs should minimise both environmental and ow-to-ow mehanisms of spread even though one may dominate in individual herds. Key elements in the ontrol of Strep uberis mastitis are disussed in order of priority: At the time of drying off: to remove existing infetions and prevent new infetions whih tend to our early in the dry period. In the transition and alving periods: to minimise exposure of suseptible ows to faeal ontamination, maximise immunity, ensure that ows are milked as soon as possible after alving and monitor losely for signs of linial mastitis. During latation: to minimise the risk of teat end damage and redue the number of bateria on the teat skin. To get good take-up of all reommendations it is important to have the whole team on the farm understand the approah to be implemented. For Strep uberis herds this inludes milking staff and those involved in paddok work and feeding. Strep uberis does not simply disappear. A suessful ontrol program an take more than a year to ahieve beause eah ow will need to go through a full yle of the required drying-off, alving and milking management. The plan for ontrolling Strep uberis in a dairy herd requires this timeframe and it is important that the farm team have realisti expetations of progress. Page 5

6 At the time of drying-off... A good dry ow strategy and drying-off proess is the most important ontrol step to get right in Strep uberis herds. The plan must hek off all of the steps that the farm team will need to manage in the lead up to drying-off, in hoosing and using appropriate treatment strategies (antibiotis and teat sealants), and managing ows after they are dried-off (see example on page 10). Use dry ow treatments to ure existing infetions and protet ows The main opportunity to ure Strep uberis infetions that have ourred is with antibioti Dry Cow Treatment. The drug of hoie is often a longer-ating preparation. The produt to be used should be disussed with the farm s veterinarian. Strep uberis an enter the udder while the teat anal is still losing in the days after drying-off (Leigh 1999). The main objetive for prevention of infetion is to ensure that teat anals remain sealed throughout the dry period. The use of teat sealant has signifiantly improved the suess of farms in ontrolling Strep uberis mastitis. Tehnote 14 desribes the losure of the teat anal during the dry period. In herds where seletive antibioti Dry Cow Treatment is an option, inluding teat sealant in the treatment regimen for ows with Individual Cow Cell Counts under 250,000 ells/ ml should be onsidered. Tehnote 16 explains the importane of drying ows off when they are produing between 5 to 12 L per day and why it is neessary to plan for this. For herds where maiden heifers are beoming infeted, the use of teat sealants (alone) in the 2-8 weeks prior to alving an markedly redue the inidene of linial mastitis in the post-alving period (Parker et al 2007). Minimise ontamination of udders after drying-off Teat skin must be ompletely overed with teat disinfetant after drying-off treatment. Cows should be moved out of the shed to a lean area and enouraged to stand (for example by having feed available) for at least an hour so that udders don t beome ontaminated. The Teat sealants FAQ Sheet (Feb 2003) desribes the use of inert ompounds to protet uninfeted ows for the duration of the dry period. Freshly dried-off ows must go into an area with minimal faeal ontamination (not grazed for at least two weeks beforehand) for at least a week after Dry Cow Treatment. It is preferable not to transport ows immediately but if they must be transported or walked after treatment it is an additional indiation to use teat sealant. Cull persistently infeted ows If they haven t been ulled already, drying-off is the opportunity to remove ows that have had three or more linial ases during this latation or ell ounts above 250,000 ells/ml in the last two latations despite reeiving antibioti Dry Cow Treatment. These ows are likely to be arrying hroni Strep uberis infetions that may present a risk to other ows. Cheklist for Drying-off Plan STOP The udder needs a lear message to stop making milk. SEAL Eah teat needs a quik, lean seal in the teat anal. A natural seal takes days, a Teat Sealant operates immediately. HEAL The udder needs time to remove and repair milk-produing tissue, and help from antibiotis to remove infetions. Get the timing right What length dry period do you want? There are issues suh as feeding, ow ondition and time for staff holidays to onsider. You may deide to dry-off high ell ount ows early. How aurately an you estimate alving dates? Do you have preg test reords? How will you manage ows to dry off when they are produing between 5 and 12 litres per day? What s required to ensure that newly treated ows an go to a lean loation? Get everything you need ready Have you disussed the hoie of produts with your veterinarian and purhased what you need tubes, teat wipes, et? Get the administration tehnique right If a Dry Cow Treatment or Teat Sealant is administered poorly it an arry bateria into the udder. It is essential to get it right. Do you have suffiient time/people alloated? Plan to do bathes to do the job well you an only treat about 20 ows per hour. Can everyone who is involved do the job well? Provide a training session for anyone administering Antibioti Dry Cow Treatment or Teat Sealant or both. After the ows are treated... Will the ows go into a lean area for at least a week after Dry Cow Treatment. Never put them in areas that have had effluent spread. Don t transport ows immediately if you an help it. If ows must be transported or walked, will you use a Teat Sealant? What proedure will you use for heking ows for swollen quarters for the next week. Who will do it? How? When? Preferably don t bring ows bak through the shed. How will you deal with ows that leak milk? Page 6

7 In the transition and alving periods... In the period leading up to and immediately after alving it is extremely important to minimise exposure of ows udders to faeal ontamination and ensure that teat anals remain losed. Use good transition management programs to promote ow health Healthy ows spend more time on their feet and less time lying down in ontat with potentially ontaminated soil and pasture. Plan and implement a good transition feed management program to keep the inidene of milk fever at or below the target levels of 1-2%. Apply the normal post-milking teat disinfetion when the transition diet is being fed in the milking shed (MDougall et al 2010, Lopez-Benavides et al 2007). Disinfet eah teat of eah animal at eah feed. InCalf desribes a pratial approah for reduing retained foetal membranes, aidosis and milk fever at alving in the transition management fat sheet Springers: repro ready at Control udder oedema and leaking milk before alving With the advent of onentrate-based transition ow rations in the mid-1990s there has been an inrease in ows that have udder oedema and leak milk lose to alving. The same is true for heifers fed a transition onentrate ( lead feed ). Animals that drip milk prior to alving or have udder oedema (flag) have patent teat anals and are at risk of linial and sublinial infetion with environmental bateria suh as Strep uberis. If springing ows and heifers drip milk prior to alving, milk them twie a day and disinfet their teats after milking. Store olostrum from these animals (or from an alternative soure) to feed to their alves. Use the same proess for heifers displaying udder oedema even when they are not observed leaking milk. Cows and heifers with severe udder oedema may be milked more easily if they are indued to alve. Minimise faeal ontamination of alving and feeding areas Wherever ows and heifers are alved it is important to keep the area as lean as possible. Having ows in groups based on expeted alving date an assist in managing the population density of alving areas. Where possible hose paddoks with good drainage and keep them free from ows for a few weeks to minimise ontamination and ahieve some grass over before the springers arrive. For ows alving on pasture, provide a lean break of feed eah day by bak fening to stop grazing over previously ontaminated areas. Calving pads an be diffiult to manage well. Sraping dirt-based alving pads weekly, and sraping or hosing onrete alving pads daily, removes dung pats and soiled material but an also spread faeal material aross the area. Some field reports indiate an inrease in Strep uberis mastitis after dirt-based alving pads have been sraped. The alving pad an be a handy plan B area to use for a few days at a time if there are periods of very wet weather during alving. If using bedding material, maintain a fresh surfae. Sand is often preferred as it is a less favourable substrate for Strep uberis than organi materials (Leigh 1999). However, well-maintained straw bedding also does the job (fresh straw bedding has a lower baterial load than sand that is not regularly replaed for example). Setting up a routine that maintains bedding with fresh material should be a prime onsideration for farms that have moved to a total mixed ration feed system with free stall housing. A new alving area should be used if the linial mastitis rate at alving goes above 5 ases per 100 freshly alved ows per month or when there is a notieable inrease in the linial ase rate among alving ows. Maintain as lean an area as possible wherever ows and heifers are being fed prior to and after alving. Milk freshly alved ows and heifers as soon as possible Get freshly alved ows and heifers into the milking herd as soon as possible, preferably within 12 hours of alving (rather than 24 hours). Monitor losely for signs of linial mastitis by visual appraisal or quarter stripping all freshly alved ows. Strep uberis ases that are deteted early are more likely to respond to treatment. Tehnotes 4.1 and 5.2 desribe routines for heking for linial mastitis and foremilk stripping in fresh ows. During latation... The key to ontrolling Strep uberis in herds during latation is to minimise the risk of teat end damage and redue the number of bateria on the teat skin. Ensure milking mahine operation is not damaging teat skin or teat ends Damage to teat ends predisposes ows to Strep uberis infetions. Assessment of the mahine funtion during milking is essential during the investigation of a mastitis problem. Milking time observations, espeially teat soring, are also reommended on a regular (3-6 monthly basis) while ontrol measures are being implemented. Organise for a omplete AMMTA dry test. This will onfirm whether mahine settings suh as pulsation, vauum and liner shell ompatibility are adequate. Have a Countdown-trained milking mahine tehniian also ondut a milking time performane test on the plant. Have an experiened milk quality adviser ondut milking time observations to assess if teatups are frequently slipping, ows are unomfortable during milking, they milk slowly or inompletely, or teats are abnormal or are open after ups ome off. Revised Tehnote 13 (February 2003) ontains a Mastitis Investigation Pak with a reording sheet for teat ondition (Sheet I). This is available from Tehnote 9 desribes how to sore teats and interpret the findings. Mahine fators, milking management and environmental fators an all ause teat damage. Put ups on lean, dry teats Milking routines in Australia and New Zealand plae emphasis on preparing ows to promote good let down but most milking staff do not wash and dry dirty or soiled Page 7

8 teats. Cleaning and disinfeting teats prior to ups-on may redue the inidene of new infetions (Zadoks 2007). Wash all dirty or soiled teats (not udders) using low-pressure water. Teats that needed to be washed must then be individually dried with one paper towel per ow. In rotary dairies the ups on position may need to be hanged to aommodate this. Washing and drying dirty teats prior to milking means mastitis-ausing bateria are less likely to enter the teat during milking. Drying teats prevents up rawl and damage to teat ends. Washing and drying of teats is espeially important during wet, muddy, humid onditions where many ows are entering the milking shed with soiled teats. Where there is evidene of an inrease in linial mastitis aused by E oli a herd may onsider the use of pre-milking teat disinfetion. Care should be taken to only use a teat disinfetant registered for this purpose and the produt should be used aording to the manufaturer s reommendations. In all irumstanes these produts are designed to have a ertain ontat time on the teats and then be removed through wiping prior to ups being plaed on teats. In extreme situations (adverse environmental onditions or when dealing with an outbreak of linial mastitis) it is worthwhile putting an extra person into the shed to fous on ritial proedures before, during and immediately after milking. This inludes: ensuring teats are washed and dried before ups go on; stripping ows every day to detet, treat and isolate linial ases; and thoroughly applying post-milking teat disinfetion. Implement effetive post-milking teat disinfetion Post-milking teat disinfetion with emollient redues the number of bateria on the teat skin and helps maintain teat skin health between milkings, provided overage is adequate and the produt is used at the orret onentration. Use a produt that ontains emollient. Use a Ready-To-Use produt if water quality flutuates or is unertain. Chek that the volume of produt used allows 20 ml per ow per milking. Chek that the overage on individual teats is adequate. Best pratie is to over all parts of the teat skin in ontat with the liner. For herds that use automati teat sprays, onsider swithing to hand spraying when onditions are wet or muddy. Tehnote 7 desribes how to hek teat overage and other signifiant onsiderations when reviewing the post-milking teat disinfetion proedure used on farm. The milking hygiene and routines reommended in the Countdown Downunder Farm Guidelines for Mastitis Control should be established pratie on farms. Chek that all milking staff wear gloves at milking and ups-on and ups-off proedures are not ontributing to the risk of new infetion. Tehnotes 5 and 8 reap the main onsiderations here. Detet, treat and isolate linial ases as early as possible Clinial ases that are treated early have a better hane of ure. Isolation and treatment redues the hane of infetion spreading to other ows. At times of high risk strip quarters before every milking to hek for new linial infetions, hanges in milk or an abnormal quarter. Disuss ideas with the farm team about ways of making this do-able as a routine, for example stripping two teats of every ow at eah milking (front in the morning, bak in the evening). Rehek suspet ows at the next milking (ows with fleks in one or two strips before the milk hanges to normal). Milk linial ases last or use a separate luster attahed to a test buket. Strep uberis has been isolated from liners after two ows have been milked following a ow shedding the bateria (Zadoks et al 2001). Run a separate hospital herd of mastitis ases and others (suh as lame ows). Set up a mastitis treatment protool in onsultation with the farm veterinarian. Tehnote 4 explains the ritial elements of managing linial ases in fresh ows. Minimise exposure of ows to faeal ontamination Manage how ows use highly traffiked areas before and after milking. Exposing ows to medium or high traffi areas is likely to inrease new infetion rates (Zadoks 2007). Regard any area that ontains a lot of fresh faeal material (deposited within the past few days) as an infetion risk. Minimise rowding and pushing in the dairy yard as ows are waiting to be milked. Use baking gates judiiously. Fix areas in laneways and gateways that are high risk for splashing faees or at least use temporary fening to restrit aess to these areas. Set up a routine so ows don t lie down in the hour after milking. For example have feed available when ows leave the shed (on feed pads). Design feed pads for regular and easy leaning, and effetive draining. The Grains2Milk fat sheet provides information on the design of feeding areas. This is available at Review progress Conditions that predispose to environmental infetion or ow-to-ow spread of Strep uberis an (and do) hange. Regular reassessment of risk fators on every farm is neessary to ahieve mastitis ontrol. In all herds the desribed Countdown triggers provide the ability to measure the effetiveness of tailored ontrol plans. The triggers for review and re-planning are: linial mastitis ase rate during the alving period of 5 or more ases per 100 alvers linial ase rate during latation of greater than 2 ases per 100 milkers per month overall new infetion rate (based on Individual Cow Cell Count hanges) of 5 ases per 100 milkers per month. Page 8

9 These measurements are provided on a Countdown Mastitis Fous report. In all senarios, the use of ulture information from linial ases is integral to reviewing progress on farm. Key papers Hillerton JE, Kliem KE. Effetive treatment of Streptoous uberis linial mastitis to minimize the use of antibiotis. J. Dairy Si. 2002; 85: Hogan JS, Smith KL. Ourrene of linial and sublinial environmental streptoal mastitis. In: Proeedings of the symposium on udder health management for environmental streptooi, Ontario Veterinary College, Canada, Leigh JA. Streptoous uberis: A permanent barrier to the ontrol of bovine mastitis. The Veterinary Journal 1999; 157, Lopez-Benavides MG, Williamson JH, Pullinger GD, Lay-Hulbert SJ, Cursons RT, Leigh JA. Field Observations on the variation of Streptoous uberis populations in a pasture-based dairy farm. J. Dairy Si. 2007; 90: Lopez-Benavides MG, Williamson JH, Lay-Hulbert SJ. Teat spraying before alving and Streptoous uberis linial mastitis in heifers. Proeedings of the New Zealand Soiety of Animal Prodution MDougall S. Prevalene of linial mastitis in 38 Waikato dairy herds. Proeedings of the New Zealand Soiety of Animal Prodution pg 76-78, 1998 MDougall S, Compton C. Controlling mastitis in pasture based systems Proeedings of the 3rd AVA/NZVA Pan Paifi Veterinary Conferene, Brisbane 2010 Parker KI, Compton C, Anniss FM, Weir A, Heuer C, MDougall S. Sublinial and linial mastitis in heifers following the use of a teat sealant prealving. J. Dairy Si. 2007; 90: Petrovski KR, Heuer C, Parkinson TJ, Williamson NB. The inidene and aetiology of linial bovine mastitis on 14 farms in Northland, New Zealand. New Zealand Veterinary Journal. 2009; 57(2), Phuektes P, Mansell PD, Dyson RS, Hooper ND, Dik JS, Browning GF. Moleular epidemiology of Streptoous uberis isolates from dairy ows with mastitis. Journal of Clinial Mirobiology. 2001; 39: 4, Runiman DL, Malmo L, Deighton M. The use of an internal teat sealant in ombination with loxaillin dry ow therapy. J. Dairy Si. 2010; 93 : Tamilselvam B, Almeida RA, Dunlap JR, Oliver SP. Streptoous uberis internalizes and persists in bovine mammary epithelial ells. Mirobial Pathogenesis 2006; 40: Zadoks RN, Allore HG, Barkema HW, Sampimon OC, Grohn YT, Shukken YH. Analysis of an outbreak of Strept oous uberis mastitis. J. Dairy Si. 2001; 84: Zadoks RN. Soures and epidemiology of Streptoous uberis, with speial emphasis on mastitis in dairy attle. CAB Reviews: Perspetives in Agriulture, Veterinary Siene, Nutrition and Natural Resoures , No. 30 Zadoks RN, Fitzpatrik JL. Changing trends in mastitis. Irish Veterinary Journal. 2009; 62 Supplement pg 59-70, 2009 More information Contat Dairy Australia T F E enquiries@dairyaustralia.om.au Membership Hotline on freeall