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).

Mastitis therapy in organic dairy herds

The organic standards (UKROFS) do not limit the choice of mastitis therapy. Prompt treatment is encouraged on animal welfare grounds. The use of alternatives to antimicrobials is encouraged. 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, UKROFS, 2000).

A survey of 16 organic dairy farms in the UK showed that organic farmers used significantly less antibiotics to treat clinical mastitis than the sample of conventional dairy farmers (Hovi and Roderick, 1999). Average use across all farms was 0.9 intra-mammary tubes per case and 4.3 tubes per case in the organic and conventional groups, respectively. Although 40% of all cases on organic farms were treated with antibiotics, 65% of these were concentrated on two farms.

Homeopathy was the main alternative to antibiotic therapy on organic farms, accounting for approximately 50% of all treatments. The range of other alternative therapies was very limited. It was evident that more support and research is needed to help organic farmers to identify and use alternatives to antibiotics. In particular, advice is needed to help organic producers to improve the targeting of both antibiotic and alternative treatments.

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. 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). therapy

The use of homeopathy increased on most survey farms during the two-year observation period. The use of ready-made, homeopathic "mastitis remedies" also increased during the survey, 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.

The number of other alternative therapies adopted by the organic survey farms was limited, with the most common being the udder liniments Uddermintä and Golden Udderä . Cold water massage was used regularly on one farm only. The main reason cited for the low-level adoption of alternative measures was their incompatibility with loose housing and rapid throughput parlours. Generally, there was great interest in alternative therapy forms amongst organic farmers and several tested various alternatives during the survey. Notably, support therapy was more common in combination with homeopathy than with antibiotics.

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, they seldom cause residue problems or have harmful side effects and they are not associated with public health risks, such as antimicrobial resistance development. 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.

Homeopathy and mastitis prevention and therapy

Homeopathy is widely used and recommended for both mastitis prevention and treatment (Macleod, 1981; Hansford, 1992; Duggeli et al., 1998). It was the main alternative or complement to antibiotic therapy in a survey of UK organic farmers (Hovi and Roderick, 1999), with over half of all treatments being homeopathic. A total of 13 out of the 16 surveyed farms used homeopathy to a lesser or greater extent, and the same number of farms used homeopathic nosodes to prevent mastitis or to control SCC levels.

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), 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). This may well be a reflection of the complex nature of homeopathic prescription and the lack of expertise among both the users and the researchers.

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). 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. A cow side test for SCC levels would be useful on organic farms to determine an adequate withdrawal period.

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).

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, particularly flunixin meglumine, can have a beneficial effect on the inflammatory process in acute mastitis (Lohuis et al., 1989). This analgesic, however, needs to be administered by a veterinary surgeon, requires a long milk withdrawal and has a very short-lived impact on pain associated with mastitis (Fitzpatrick et al., 1998). 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.

Antibiotic dry cow therapy in organic herds

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 both for not being cost-effective (Howard et al., 1990) and 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).

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.).