Methods of Treatment

Introduction

The bovine udder has a capacity to clear itself of infection without therapy. In the case of some pathogens, like E. coli, the self-cure rates can be as high as 90% (Sandholm, 1995). The purpose of mastitis therapy is to assist the affected quarter to clear infection as rapidly as possible and to enable a quick return to normal milk production. The therapy should also be directed to alleviating pain and discomfort caused by inflammation associated with mastitis (Hillerton, 1998) except in cases of toxic mastitis where treatment of cases of toxic mastitis is an emergency and should be undertaken by a veterinary surgeon.

Treatment of toxic mastitis

Cows with toxic mastitis are often in, or at risk of endotoxic shock. Therefore treatment should include administration of supportive therapies. The cow may require administration of fluids, and the use of hypertonic saline intra-venously can be very effective in increasing the circulating blood volume, although it is imperative that the cow either drinks water herself or is given water (30- 50 litres depending on size of cow) by stomach tube following use of hypertonic saline. Additionally, the use of non-steroidal anti-inflammatories (flunixin meglumine) can relieve pain help reduce the pyrexia if present and can help combat the endotoxins. Administration of antimicrobials is also advised as the cow’s immune system will be severely compromised at this time. Above all, cows should receive plenty of nursing, including frequent turning if recumbent an frequent stripping out of the affected quarter(s) to help remove the altered milk which will contain endotoxin.


Mastitis therapy in organic dairy herds (mild to moderate cases)

The organic standards (Anon, 2005) do not limit the choice of mastitis therapy. Prompt treatment is encouraged on animal welfare grounds. The use of alternatives to antimicrobials is encouraged ‘where effective’. However, there is considerable debate over the effectiveness of homoeopathic and other alternative remedies and the use of unlicensed products in food producing species is an area of concern. Antibiotic therapy is indirectly discouraged by prolonged milk withdrawal times of up to three times the statutory period. Antibiotic use is further discouraged by stipulating that an animal may lose its organic status if it is subject to antibiotic therapy more than three times in any one year of its life (EU Regulation 1804/1999, Anon, 2005). From a practical perspective, any alternative treatment plan is likely to achieve better success if it does nt take up excessive time and can be fitted into existing management on the farm, i.e. treat during milking time (Hovi, 2004).

Surveys of organic dairy farms in the UK have found that organic farmers use significantly less antibiotics to treat clinical mastitis than conventional dairy farmers (Hovi and Roderick, 1999; Ellis, 2005). However, it was also found that frequency of antimicrobial use on organic farms varied between individual farms in both studies and depends very much on the philosophy of the individual farmer. In Danish studies, organic farmers who have recently converted from conventional production reported that antimicrobial treatment is the method with the most predictable effects and therefore one which they favour (Vaarst et al., 2003). Thus, suggesting that mastitis control in organic herds is something which takes a prolonged period to adjust to.

Homeopathy was the main alternative to antibiotic therapy on UK organic farms (Hovi and Roderick, 1999; Ellis, 2005), accounting for approximately 50% of all treatments in the study by Hovi and Roderick (1999). The range of other alternative therapies was very limited. In a Dutch study, 80% of organic farmers used antibiotics against clinical mastitis and, although 50% were using homoeopathy, the majority of farmers were doing so as an adjunct to antibiotic therapy (Smolders et al., 2005). It is evident that more support and research is needed to help organic farmers optimise udder health without recourse to antimicrobials. In particular, advice is needed to help organic producers to improve the targeting of both antibiotic and alternative treatments and to encourage the investment in time that is required when alternative therapies are used. Farmers wish minimum effort therapies (Vaarst, 2005), which is perhaps not surprising as many farmers have limited labour, but may require a fundamental re-assessment of the priorities of a farmer when choosing to farm organically.

Both organic and conventional farms used antibiotics in a similar manner, with intramammary application being the most common form of therapy. It was evident that the use of bacteriological examination to identify the mastitis pathogen or to target the antibiotic therapy was not common on either organic or conventional farms. Hovi and Roderick (1999) found the use of antibiotics in excess of the manufacturer’s recommendations was very common, but more so on conventional farms (68.5% and 18.5 % of all antibiotic treatments, respectively).

Most homoeopathic remedies used were ready-made "mastitis remedies", probably due to their ease of use and the lack of other advice and support. Advice on the use of homeopathic remedies came mostly from homeopathic pharmacies or retailers.

Alternative therapies adopted by organic farmers include frequent stripping out, cold hosing and application of udder creams and ointments, for example Uddermint™ and Golden Udder™. Notably, Hovi and Roderick (1999) found that support therapy was more common in combination with homeopathy than with antibiotics. The main reason cited for the low-level adoption of alternative measures was their incompatibility with loose housing and rapid throughput parlours. Generally, there is great interest in alternative therapy forms amongst organic farmers.

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Antibiotic therapy

The emphasis of clinical mastitis treatment has been on antimicrobial therapy since antibiotics were first introduced to production animal medicine in the 1940s (Bramley and Dodd, 1984).The main advantages of antibiotic mastitis therapy are the potential high cure rates when the treatment is well targeted and ease of use that suits modern dairy management systems. The main disadvantages are potential residues in milk, the development of antimicrobial resistance, disruption of symbiotic gut flora of the host when systemic administration is used and interference with phagocytic activity in the udder when lipid soluble intramammary preparations are used (Erskine, 1998; Paape et al., 1990; Sandholm et al., 1990).

Antibiotic therapy should be encouraged in the treatment of mastitis caused by Streptococcus agalactiae as this pathogen is zoonotic (causes disease in humans) and is easily eradicated from a herd. When this pathogen is identified in an organic herd a veterinarian should be contacted and an eradication plan should be implemented.

Antibiotic mastitis therapy should always be supervised by a veterinarian. All licenced antibiotic preparations for mastitis treatment in the UK require milk withdrawal periods twice as long as the statutory period. If the preparation is used in different manner from the manufacturer’s recommendations, a 7–day withdrawal period needs to be observed. As some certifying bodies require longer withdrawal periods for milk (up to 14 days) after antibiotic treatment, this should be checked before establishing a withdrawal and recording routine.

Alternative therapies

A multitude of mastitis therapies have been used before and after the advent of antibiotic therapy. These include the use of frequent stripping, herbal udder ointments and liniments, massage, phytotherapy, diet changes, clay therapy and homeopathy (Duval, 1995). The use of oxytocin combined with frequent stripping is a more "modern" alternative therapy (Knight et al., 1997). Most alternative therapies are aimed at helping the cow’s own defence mechanisms to clear the infection rather than attacking the pathogen directly as is the case with antibiotics.

The main advantages of these therapies are that they work together with the cow’s own defence mechanisms to clear the infection and they often do not have long withdrawal periods. However, many of these therapies are time-consuming, labour intensive and often require separation of the treated animal from rest of the herd. They are consequently poorly suited for modern cow housing and milking systems with loose housing and rapid throughput parlours. Since very few are classified as licensed medicines, there is no requirement for clinical testing. Consequently, there is little information regarding their efficacy (see below). The risk of fraudulent or ineffective products being marketed also increases in the absence of statutory monitoring. The producers should be particularly careful not to use preparations that are not licensed for intramammary use, as these can either cause damage to the udder or lead to residues in milk.

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Homeopathy and mastitis prevention and therapy

Homeopathy is widely used in the UK and in Europe, alone, or as an adjunct to other therapies (Hovi and Roderick, 1999; Ellis, 2005) and is recommended for both mastitis prevention and treatment (Macleod, 1981; Hansford, 1992; Duggeli et al., 1998). There is, however, very little evidence of the efficacy of homeopathy in either curing or preventing mastitis in dairy cows. Whilst a substantial body of anecdotal evidence about successful mastitis therapy or prevention exists (Leon et al., 1999; Andersson, 1996; Merck et al., 1989; Tiefenthaler, 1994; Tiefenthaler, 1995; May and Reinhart, 1993; Martini et al., 2001), several review papers and published experimental work have all drawn the conclusion that homeopathy has no beneficial effect or that its efficacy has not been proven (Meaney, 1995; Andersson et al., 1997; Andersson and Leon, 1999; Hamann, 1993; Jonsson and Ekman, 1996; Schutte, 1994; Stopes and Woodward, 1990; Egan, 1998; Turner, 2001; Hektoen, 2004; DEFRA, 2007). In particular homoeopathy has been reported to have a poor effect in subclinical mastitis (Walkenhorst et al., 2001) and Staph aureus treatment (Tikofsky and Zadoks, 2005), although treatment effects may be seen in cases of acute mastitis as the cow has a better chance to react against infect compared to a cow with chronic mastitis (Walkenhorst et al., 2001). The apparent lack of effect of homoeopathy may also be a reflection of the complex nature of homeopathic prescription and the lack of expertise among both the users and the researchers (Hektoen, 2001).

A detailed description of the principles of homoeopathy as well as other alternative therapies, including suggested approaches to utilising alternative therapies in cattle is given by Day (2004).

In the light of this lack of understanding of the usefulness of homeopathy and the wide-spread use of homeopathy among organic dairy farmers, the importance of good recording of all treatments, including the outcomes of the treatments, on farms that use homeopathy should be emphasised.


Milk withdrawal after alternative therapies

A survey of organic farmers in the UK found that the milk withdrawal periods observed after a case of mastitis were very short (less than 3 days) after the use of homeopathic or other alternative therapy that did not have a statutory withdrawal period (Hovi and Roderick, 1999). Studies in Denmark have also found that treatment periods on organic farms tend to be shorter than on conventional (Vaarst and Bennedsgard, 2001). It is important that milk is withdrawn from the bulk tank for an adequate period of time to prevent high SCC milk from entering the food chain. Use of cow side test for SCC levels (such as the CMT) is useful on organic farms to determine an adequate withdrawal period.

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Mastitis therapy and pain relief2.4.4 Mastitis therapy and pain

An important aspect of mastitis therapy is the alleviation of inflammation in the udder. Swelling and subsequent pain associated with clinical mastitis can cause considerable discomfort to the cow. In the light of recent research findings on subjective pain measurement in mastitic cows, pain relief should be an important objective of mastitis therapy (Fitzpatrick et al., 1998; Barrett, 2004).

Antibiotic preparations offer no immediate relief from pain. Whilst the inclusion of steroid anti-inflammatory components in intramammary preparations has very little effect on the inflammation, systemic use of non-steroidal anti-inflammatory agents, can have a beneficial effect on the inflammatory process in acute mastitis (Lohuis et al., 1989). There are a number of non-steroidal anti-inflammatory drugs (NSAIDS) now licensed for cattle and their use should be encouraged to relive pain associated with mastitis. However, these products have a relatively short duration of action (Fitzpatrick et al., 1998), requiring repeat administration over a period of days and may be associated with side effects such as abomasal ulceration, although this is not well characterised. Use of oxytocin and frequent stripping is likely to alleviate some pain by relieving the tension in the affected quarter, but no published information on its efficacy is available. Similarly, many alternative therapy forms, including udder liniments, clay therapy and cold water massage, are likely to alleviate pain by increasing circulation and reducing swelling.


Prevention and treatment of mastitis in dry cows

The efficacy of antibiotic DCT in mastitis therapy, curing chronic infections and protecting against new infections during the dry period, is widely recognised (Ziv et al., 1987). However, routine DCT of all cows, independent of their udder health status, has been criticized for potentially contributing to the development of antimicrobial resistance on farms (Huda et al., 1997). The apparent control of contagious pathogens like Str. agalactiae and S. aureus in England and Wales has been attributed to the "blanket" antibiotic use at drying-off (Booth, 1997).

Using an internal teat sealant (Orbeseal, Pfizer Ltd) can provide protection against new infections in the dry period but it is important to emphasise that this will not specifically ‘treat’ existing infections. Selection of cows for use of ITS is therefore important, as only those cows with no current infection at drying off should be considered. It is recommended that cows with a cell count of consistently <200,000 cells per ml at drying off and no previous cases of clinical mastitis should be selected. However, these criteria are difficult to meet in the field and a modification of the selection criteria, based on the knowledge of the individual farm can be utilised (see Practical Advice at the end of this chapter).

The use of antibiotic DCT in organic herds can be justified on a selective basis and as a part of planned mastitis reduction strategy. Written permission has to be sought from the certifying body, detailing why the strategy is implemented (high levels of SCC or clinical mastitis, bacteriological identification and likelihood of success of the chosen preparations etc.), how the cows are selected for treatment (identification of infection/pathogen, SCC levels in previous lactation etc.) and how antibiotic residues are prevented in milk after calving (residue testing before inclusion in the bulk, prolonged withdrawal after calving etc.).

Selection of appropriate approaches to dry cow mastitis treatment and prevention is an area where the veterinary surgeon can help the farmer as part of the herd health plan by drawing-up a farm-specific decision support tree to be used to determine which cows receive antimicrobial DCT and which cows receive an alternative approach.

For most recent information on different sector body requirements on withdrawal periods for livestock products following medicinal use please see

Withdrawal of Products following medication.

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