Risk factors for bulk milk somatic cell counts and total bacterial counts in smallholder dairy farms in the 10th region of Chile

We investigated the principal management factors that influenced bulk milk somatic cell count (BMSCC) and total bacterial count (TBC) of smallholder dairy farms in the 10th region of Chile. One hundred and fifty smallholder milk producers were selected randomly from 42 milk collection centres (MCCs). In April and May of 2002, all farms were visited and a detailed interview questionnaire on dairy-cow management related to milk quality was conducted. In addition, the BMSCC and TBC results from the previous 2 months' fortnightly tests were obtained from the MCCs. The mean BMSCC and TBC were used as the dependent variables in the analyses and were normalised by a natural-logarithm transformation (LN). All independent management variables were categorised into binary outcomes and present (=1) was compared with absent (=0). Biserial correlations were calculated between the LNBMSCC or LNTBC and the management factors of the smallholder farms. Management factors with correlations with P0.05) factors. A random MCC effect was included in the models to investigate the importance of clustering of herds within MCC. In the null model for mean LNTBC, the random effect of MCCs was highly significant. It was explained by: milk collected once a day or less compared with collection twice a day, not cleaning the bucket after milking mastitic cows versus cleaning the bucket and cooling milk in a vat of water versus not cooling milk or using ice or a bulk tank to cool milk. Other factors that increased the LNTBC were a waiting yard with a soil or gravel floor versus concrete, use of plastic buckets for milking instead of metal, not feeding California mastitis test (CMT)-positive milk to calves and cows of dual-purpose breed. The final model explained 35% of the variance. The model predicted that a herd that complied with all the management practices had a mean predicted TBC of 105 colony forming units (cfu)/ml, whereas a herd that did not comply with any of these management factors had a predicted TBC of 59 x 10(9)cfu/ml. The model of mean LNBMSCC explained 18% of the variance; the random effect of MCC was not significant. Management factors that decreased the mean LNBMSCC were: using the CMT for 1 year versus using the test for more than 1 year or not at all, absence of a concrete waiting yard, not filtering the milk or using filters other than a plastic sieve to filter the milk, milking cows with mastitis last, and sometimes or always examining the udder before milking. A herd that complied with all of these management factors had a BMSCC of approximately 46,166 cells/ml, whereas a herd that did not comply with any of the management practices above had a mean BMSCC of 2 x 10(6)cells/ml.     

Quarter,cow, and farm risk factors for intramammary infections with major pathogens relative to minor pathogens in Thai dairy cows

A cross-sectional study was carried out from May to September 2011 on 35 smallholder dairy farms in Chiang Mai, Thailand, to identify the quarter, cow, and farm factors that relate to intramammary infections (IMI) from major specified pathogens, compared to infections from minor pathogens. Data on general farm management, milking management, and dry cow management were recorded for each herd. Quarter milk samples were collected from either clinical or subclinical mastitis quarters. Dependent variables were binary data defining the specified major pathogens, including Streptococcus agalactiae (7.1 %), Streptococcus uberis (9.4 %), Streptococcus dysgalactiae (4.0 %), and other streptococci (16.7 %), as a case, and all minor pathogens as a control, in each dependent variable. The occurrence of S. agalactiae IMI was lower in first-parity cows and cows with short milking time. Cows with body condition score (BCS) <2.5 had higher occurrence of S. agalactiae IMI. The occurrence of S. uberis IMI was higher in quarters with California mastitis test (CMT) score 2, score 3, and having clinical mastitis and in farms with increasing age of vacuum system. Quarters with CMT score 3, having clinical mastitis, cow with manual milking after detaching milking cluster, and farms with high bulk milk somatic cell counts (BMSCC >500,000 cells/ml) had higher occurrence of S. dysgalactiae IMI. For other streptococci, quarters having clinical mastitis, BCS <2.5, and pulling down of milking cluster while milking increased occurrence of other streptococci IMI relative to minor pathogen IMI. These results highlight the importance of individual cow factors, milking characteristics, and BMSCC in determining the risk of IMI from major pathogens.     

Impact of Mastitis Control Measures on Milk Production and Mastitis Indicators in Smallholder Dairy Farms in Kiambu District,Kenya

Bovine mastitis and mastitis control were investigated on smallholder farms in central Kenya. After an initial observational study, a clinical trial to assess the impact of three different mastitis control strategies – (1) improved udder hygiene, (2) treatment of subclinical cases, and (3) a combination of these – was conducted on 100 randomly selected farms with 332 lactating cows. Before the implementation of control measures, the milk yield was low (mean 6.5 kg/day; median 6 kg/day) and somatic cell counts (SCC) were high, with 80% and 43% of cows having milk with SCC greater than 250×10³ cells/ml and 600×10³ cells/ml, respectively. Infectious pathogens were also commonly isolated, with 63% of cows being positive for pathogenic bacteria. Neither intervention strategy alone had any effect on mastitis indicators or milk yield. In combination, the measures had some impact, lowering the prevalence of contagious pathogens by 18%, but this was not reflected in a significantly increased milk yield, lowered SCC or reduced incidence of clinical mastitis.     

Risk factors associated with BMSCC greater than 200 000 cells/ml in dairy herds in southern Chile

A cross-sectional survey of 523 dairy farms in the south of Chile was carried out to quantify risk factors associated with bulk-milk somatic-cell count (BMSCC) >200 x 10(3)cells/ml.Questionnaires followed by one reminder were sent to 3710 dairy farms via the 11 milk-processing plants that they supplied in October 1998. The response proportion was 14.1%. The median BMSCC was 289 x 10(3) cells/ml (range: 74 x 10(3) to 1800 x 10(3)cells/ml). The median herd size was 70 cows (range: 7-616); herd size was not associated with BMSCC. The annual milk yield of 33.2% of the herds was <4000 l and 53.4% had an annual milk yield of 4 x 10(3) to 6 x 10(3) l. Clinical-mastitis records were kept by 55.3% of the farmers. Seventy-six percent of the farmers (377/499) reported <10 clinical cases of mastitis in the year prior to the questionnaire.Logistic multiple regression indicated that BMSCC >200 x 10(3)cells/ml was more likely when foremilking was practised, and when cows were collected in a yard before milking. BMSCC was less likely to be >200 x 10(3)cells/ml when teats were washed with water containing disinfectant compared with plain water; when the udder and teats were always checked before milking compared with, sometimes or never; when cows with mastitis were milked first compared with any other ordering, and when farmers recorded individual-cow somatic-cell count (ICSCC) compared with when ICSCC was not recorded.     

奶牛隐性乳房炎发病因素的研究

[目的]为了探讨奶牛隐性乳房炎的影响因素。[方法]以2009年1月至2010年1月五个大型奶牛场的5080头泌乳荷斯坦牛为试验材料,从年龄、胎次、日泌乳量、乳区等方面对其隐性乳房炎发病情况进行了调查、统计和分析,并随机选取50头患隐性乳房炎的病料,进行病原学检查。[结果]表明,试验牛群中8.5%的荷斯坦牛为临床性乳房炎阳性,45%的荷斯坦牛为隐性乳房炎阳性;并且,随着年龄、胎次、日泌乳量的不断增加,荷斯坦牛患乳房炎的几率增加;左侧乳区发病率高于右侧乳区;后侧乳区高于前侧乳区;隐性乳房炎的病原微生物主要以金黄色葡萄球菌为主。[结论]加强日常卫生管理是减少乳房炎发病的主要手段。     

Comparison between dairy cow disease incidence in data registered by farmers and in data from a disease-recording system based on veterinary reporting

Sweden has a national disease-recording system based on veterinary reporting. From this system, all cattle-disease records are transferred to the dairy industry cattle database (DDD) where they are used for several purposes including research and dairy-health statistics. Our objective was to evaluate the completeness of this data source by comparing it with disease data registered by dairy farmers. The proportion of veterinary-treated disease events was estimated, by diagnosis. Disease incidence in the DDD was compared, by diagnosis and age, with disease data registered by the farmers. Comparison was made, by diagnosis, for (i) all disease events and (ii) those reported as veterinary-treated.Disease events, defined as “observed deviations in health, from the normal” were recorded by the farmers during January, April, July and October 2004. For the diagnoses calving problems, peripartum disorders, puerperal paresis and retained placenta, incidence proportions (IP) with 95% confidence intervals (CIs) were estimated. For all other disease problems, incidence rates (IR) were used.In total, 177 farmers reported at least 1 month and 148 reported all 4 months. Fifty-four percent of all disease events in the farmers’ data were reported as veterinary-treated. For several of the most common diagnoses, the IRs and IPs for all events were significantly higher in farmers’ data than in the DDD. Examples are, in cows: clinical mastitis, cough, gastro-intestinal disorders and lameness in hoof and limb; and in young stock: cough and gastro-intestinal disorders. For veterinary-treated events only, significant differences with higher IR in the farmers’ data were found in young stock for sporadic cough and sporadic gastro-intestinal disorders. The diagnosis “other disorders” had significantly more events in the DDD than in farmers’ data, i.e. veterinarians tended to choose more unspecific diagnoses than the farmers. This result indicates that the true completeness is likely to be higher than our estimate.We conclude that for the time period studied there was differential under-reporting associated with the diagnosis, the age of the animal and whether the herd was served by a state-employed or private veterinarian.     

新疆克拉玛依地区奶牛隐性乳房炎病原菌的分离鉴定

用兰州乳房炎检测试剂(Lanzhou mastitis test,LMT)对克拉玛依规模化奶牛场进行了奶牛隐性乳房炎流行病学调查。结果显示,该地区奶牛隐性乳房炎的发病率为70.43%(543/771)。对543份阳性牛乳样品进行了病原菌的分离鉴定,结果发现,阳性乳样品中细菌分离率达89.13%(484/543),葡萄球菌、链球菌、肠杆菌和棒状杆菌为主要致病菌,且多为几种致病菌的混合感染。     

Mastitis control programme in the developing dairy industry of tropical lowland Bolivia

Mastitis is an important disease in developing dairy industries. This paper describes a commercial mastitis control programme in Santa Cruz, Bolivia, based upon the five-point mastitis control plan and bulk tank somatic cell count (BTSCC) monitoring. Twelve farms which participated on the programme for 6 years are considered. Mean annual BTSCC fell steadily from 1200000 cells/ml to 461000 cells/ml over this time. This progressive improvement was probably a result of increasing use of and attention to detail in mastitis control practices. The control of subclinical mastitis improved in both hand-milked and machine-milked herds, though hand-milked herds consistently produced milk of higher BTSCC. The mastitis programme did not appear to influence the incidence of clinical mastitis. The paper concludes that a simple mastitis programme based on the five-point plan and BTSCC monitoring can be commercially implemented and effectively control subclinical mastitis in a tropical, developing country.     

Drying off cows: a comparative study with two dry cow products

From September 1998 to September 1999, at drying off 397 cows on 73 Dutch farms were treated, with two antibiotic containing dry cow products (cloxacillin; penicillin-neomycin). Farms and cows were selected on an increased bulk milk somatic cell count (BMSCC) and individual cow somatic cell count. The objective of the trial was to compare the efficacy of both products under field conditions. Both products proved to be highly effective against streptococci and penicillin sensitive staphylococci. Because of the low incidence of infections caused by Escherichia coli and penicillin resistant staphylococci no conclusions could be drawn on differences in activity for these two pathogens. No significant differences were found between the two products in cure rate of existing infections at drying off, incidence of new infections during the dry period, incidence of clinical mastitis during the dry period and the course of the individual cow cell counts during the trial.     

奶牛乳腺炎的细菌学研究

在对山东7个地区14个奶牛场临床型和隐性乳腺炎调查的基础上采集234头临床乳腺炎病牛乳样、241个隐性乳腺炎乳样并分别做了细菌学检查,结果表明:泌乳期临床型乳腺炎病原菌以凝固酶阴性葡萄球菌、金黄色葡萄球菌、链球菌、酵母菌和棒状杆菌为主;干奶期临床型乳腺炎病原菌以大肠杆菌、链球菌、金黄色葡萄球菌、凝固酶阴性葡萄球菌和酵母菌为主;隐性乳腺炎病原菌以凝固酶阴性葡萄球菌、金黄色葡萄球菌链球菌、酵母菌、假单胞菌和棒状杆菌为主;厌氧菌在隐性乳腺炎、干奶期乳腺炎和干奶期乳腺炎乳样的捡出率分别为 5．82％,4．17%,10．16％;隐性乳腺炎、干奶期乳腺炎细菌的共感染率较高,与泌乳期乳腺炎病原菌的差异极显著(P<0．01),隐性乳腺炎与干奶期乳腺炎病原菌共感染率差异不显著(P >0．05)。     

金黄色葡萄球菌性奶牛乳房炎多价疫苗的研制和免疫效果评价

为研制用于预防金黄色葡萄球菌性奶牛乳房炎的免疫疫苗,使用4株血清型为外膜多糖336型(336PS)、荚膜多糖5型(CP5)和荚膜多糖8型(CP8)强毒力金黄色葡萄球菌试制出金黄色葡萄球菌多价疫苗,并通过抗体水平监测、攻毒保护试验以及两个牧场的田间试验对免疫效果进行了评价。抗体水平监测显示,首免后30 d即可产生较高的抗体水平,二次免疫后有效抗体水平可持续到产后210 d;人工攻毒保护试验显示,疫苗对金黄色葡萄球菌引起的临床型乳房炎的保护率为89%;田间试验结果表明,该疫苗对奶牛临床型乳房炎的保护率在75.2%～83.3%之间,对隐性乳房炎的保护率在49.9%～52.2%之间,免疫组日产奶量较对照组平均提高1.26 kg以上。上述结果表明,所试制的疫苗可以显著降低泌乳牛金黄色葡萄球菌引起的临床型和隐性乳房炎发病率并提高产奶量。     

Udder pathogens and their resistance to antimicrobial agents in dairy cows in Estonia

Background

The goal of this study was to estimate the distribution of udder pathogens and their antibiotic resistance in Estonia during the years 2007-2009.

Methods

The bacteriological findings reported in this study originate from quarter milk samples collected from cows on Estonian dairy farms that had clinical or subclinical mastitis. The samples were submitted by local veterinarians to the Estonian Veterinary and Food Laboratory during 2007-2009. Milk samples were examined by conventional bacteriology. In vitro antimicrobial susceptibility testing was performed with the disc diffusion test. Logistic regression with a random herd effect to control for clustering was used for statistical analysis.

Results

During the study period, 3058 clinical mastitis samples from 190 farms and 5146 subclinical mastitis samples from 274 farms were investigated. Positive results were found in 57% of the samples (4680 out of 8204), and the proportion did not differ according to year (p > 0.05). The proportion of bacteriologically negative samples was 22.3% and that of mixed growth was 20.6%. Streptococcus uberis (Str. uberis) was the bacterium isolated most frequently (18.4%) from cases of clinical mastitis, followed by Escherichia coli (E. coli) (15.9%) and Streptococcus agalactiae (Str. agalactiae) (11.9%). The bacteria that caused subclinical mastitis were mainly Staphylococcus aureus (S. aureus) (20%) and coagulase-negative staphylococci (CNS) (15.4%). The probability of isolating S. aureus from milk samples was significantly higher on farms that had fewer than 30 cows, when compared with farms that had more than 100 cows (p < 0.005). A significantly higher risk of Str. agalactiae infection was found on farms with more than 600 cows (p = 0.034) compared with smaller farms. The proportion of S. aureus and CNS isolates that were resistant to penicillin was 61.4% and 38.5%, respectively. Among the E. coli isolates, ampicillin, streptomycin and tetracycline resistance were observed in 24.3%, 15.6% and 13.5%, respectively.

Conclusions

This study showed that the main pathogens associated with clinical mastitis were Str. uberis and E. coli. Subclinical mastitis was caused mainly by S. aureus and CNS. The number of S. aureus and Str. agalactiae isolates depended on herd size. Antimicrobial resistance was highly prevalent, especially penicillin resistance in S. aureus and CNS.     

关于宁夏地区首次从乳房炎乳样中检出非脱羧勒克菌的研究

从宁夏部分奶牛场(牧场、养殖小区)采集94份临床型乳房炎乳样、70份隐性乳房炎乳样,并分离鉴定出4株非脱羧勒克菌,其中临床型乳房炎分离出1株、隐性乳房炎分离出3株。药敏试验结果表明,4株非脱羧勒克菌均对链霉素、氨基糖苷类、喹诺酮类、头孢类药物敏感;对磺胺类、林可胺类药物则产生不同程度的耐药性。     

Associations between the decrease in bovine clinical mastitis and changes in dairy farmers' attitude,knowledge, and behavior in the Netherlands

The aim of this study was to associate changes in dairy farmers' self-reported attitude, knowledge, and behavior with the decrease in incidence rate of clinical mastitis (IRCM). Farmer-diagnosed clinical mastitis cases were obtained from two surveys conducted before (July 2004–June 2005) and at the end (2009) of a mastitis control program in the Netherlands. Information on farmers' attitude, knowledge, and behavior was also obtained by sending the famers the same questionnaire during both surveys. Multivariable linear regression models identified that the herd level 2004 IRCM explained 28% of the variation in the decrease of IRCM. Changes in farmers' attitude and knowledge, and changes in farmers' behavior additionally explained 24% and 5%, respectively. These results suggest that the way management measures are executed may be at least as important as the fact that they are executed. No control group was available for this study because the intervention was applied at the national level. We therefore do not claim any causal relationships.     

Disposal and disease rates in 340 British dairy herds

Data derived from 340 dairy herds, mainly in southern England, between April 1998 and March 1999, showed that the average total culling rate was 22.1 per cent, with 5.6 per cent for infertility, 3.6 per cent for mastitis, 1.7 per cent for lameness, 2.0 per cent for poor milk yield, 3.7 per cent for age and 5.5 per cent for miscellaneous reasons which included death. The average annual rate of assisted calvings was 8.7 per cent, of injury 0.9 per cent, digestive disease 1.3 per cent ketosis 0.4 per cent, hypomagnesaemia 0.7 per cent, hypocalcaemia 5.3 per cent, mastitis 36.6 per cent, and lameness 23.7 per cent. There was a significant association (P<0.001) between higher rates of mastitis in cows housed in straw yards as opposed to cubicles and also between higher rates of lameness in cows housed in cubicles as opposed to yards (P<0.015). However, there were farms with low rates of mastitis in cows kept in straw yards and low rates of lameness in cows kept in cubicles. Larger herds tended to have more problems with lameness and higher bulk milk somatic cell counts (BMSCC). There was a positive association between BMSCC and mastitis rate.     

规模化奶牛场奶牛亚临床型乳房炎流行规律调查

目的 本研究旨在摸清兰考县规模化奶牛场奶牛亚临床乳房炎流行规律,为该病的防控提供参考。方法 采用加州奶牛亚临床乳房炎试验（CMT）方法对3 家规模化奶牛场的547 头泌乳奶牛进行亚临床乳房炎检测,调查该病与奶牛胎次、泌乳期和乳区的关系。结果 奶牛阳性率为20.11%,乳区阳性率为10.88%;1~2、3~4和≥5胎次的奶牛发病率分别为13.37%、20.53%和29.46%;泌乳前期、泌乳中期和泌乳后期发病率分别为15.11%、22.12%和30.89%;乳区阳性率介于8.59%~13.16%。结论 兰考县规模化奶牛场奶牛亚临床型乳房炎的发病率相对较低,与胎次、泌乳期存在正相关,与乳区无明显关系。     

Study on risk factors and their association with subclinical mastitis in lactating dairy cows in Trinidad

A cross-sectional study was conducted on dairy farms in eight milking centres in Trinidad to determine the prevalence of risk factors for mastitis and to assess their relationship to occurrence of subclinical mastitis. The California mastitis test (CMT) was used to determine the prevalence of subclinical mastitis by estimating the somatic cell counts in bulk and composite milk. Of a total of 177 dairy farms studied, 121 (68.4%), 39 (22.0%) and 17 (9.6%) practised semi-intensive, extensive and intensive management systems, respectively. A total of 129 (72.9%), 37 (20.9%) and 11 (6.2%) farms milked cows in parlours, stanchions and pasture/out-on-field, respectively. Based on sanitary practices, 40 (22.6%), 123 (69.5%), and 14 (7.9%) farms were classified as good, fair, and poor, respectively, while 76 (42.9%) and 60 (33.9%) farms reported to rarely experience and frequently experience water shortages, respectively. Amongst the 177 farms, only seven (4.0%) used machine-milking primarily, 152 (85.9%) screened for mastitis as a routine, 18 (10.2%) teat dipped, and 49 (27.7%) practised dry cow therapy. To detect mastitis, of 152 farms involved, 20 (13.2%) used the strip cup while only two (1.3%) employed the CMT. Pipe-borne water delivered directly from the hose was the only source of water to 91 (51.4%) farms while seven (4.0%) and eight (4.5%) farms used only well and surface water (ponds and rivers), respectively. Based on bulk milk samples, the farm prevalence of subclinical mastitis was 60.5% (107 of 177) with a range from 33.3% (centre 5H) to 100.0% (centre 2B). The difference was statistically significant (P < 0.01; chi 2). However, using composite milk, the farm prevalence of subclinical mastitis was 52.5% (93 of 177) with a range from 21.2% (centre 5H) to 92.9% (centre 2B) and again, the difference in prevalence was statistically significant (P < 0.001; chi 2). Subclinical mastitis was detected in 150 (45.0%) of 333 lactating cows screened and the range of prevalence was from 17.9% (centre 5H) to 56.3% (centre 1C). The difference was statistically significant (P < 0.001; chi 2). Of a total of 14 risk factors for mastitis studied which were related to animal husbandry, personnel, mastitis control and water, only two, the herd size and practice of dry cow therapy were significantly (P < 0.05; chi 2) associated with subclinical mastitis. It was concluded that the high prevalence of subclinical mastitis in Trinidad dairy herds could significantly reduce milk production with associated economic loss. Although a majority of the risk factors studied were not found to be significantly associated with the occurrence of subclinical mastitis possibly due to confounding factors, the need to eliminate or reduce these risk factors cannot be over-emphasized.     

Investigation of mastitis problems on farms.

The production of high-quality milk is a high-priority issue for dairy farmers and milk processors. The investigation of mastitis problems on dairy farms is an area of increasing demand and is an ideal way for veterinary practitioners to increase involvement in production medicine programs. Goals for the amount of clinical and subclinical mastitis should be predefined on dairy farms, and a herd investigation initiated when needed. The use of a structured approach to mastitis problems can identify risk factors for infection, result in rapid resolution of mastitis problems, and hasten the application of appropriate preventive practices.     

Clinical mastitis in dairy cattle in Ontario: frequency of occurrence and bacteriological isolates.

The objective of this study was to describe the frequency of occurrence of clinical mastitis in dairy herds in Ontario. The study group consisted of 65 dairy farms involved in a 2-year observational study, which included recording all clinical mastitis cases and milk sampling of quarters with clinical mastitis. Lactational incidence risks of 9.8% for abnormal milk only, 8.2% for abnormal milk with a hard or swollen udder, and 4.4% for abnormal milk plus systemic signs of illness related to mastitis were calculated for 2840 cows and heifers. Overall, 19.8% of cows experienced one or more cases of clinical mastitis during location. Teat injuries occurred in 2.1% of lactations. Standard bacteriology was performed on pretreatment milk samples from 834 cows with clinical mastitis. The bacteria isolated were Staphylococcus aureus (6.7%), Streptococcus agalactiae (0.7%), other Streptococcus spp. (14.1%), coliforms (17.2%), gram-positive bacilli (5.5%), Corynebacterium bovis (1.7%), and other Staphylococcus spp. (28.7%). There was no growth in 17.7% of samples, and 8.3% of samples were contaminated. Clinical mastitis is a common disease in dairy cows in Ontario; approximately 1 in 5 cow lactations have at lease one episode of clinical mastitis. There is, however, considerable variation in the incidence of clinical mastitis among farms. The majority of 1st cases of clinical mastitis occur early in lactation, and the risk of clinical mastitis increases with increasing parity. Environmental, contagious, and minor pathogens were all associated with cases of clinical mastitis.     

Economic aspects of mastitis: new developments

Good udder health is not only important for the dairy farmer but, because of increasing interest of consumers in the way dairy products are produced, also for the dairy production chain as a whole. An important role of veterinarians is in advising on production diseases such as mastitis. A large part of this advice is given around the planning of management to maintain or improve the udder health status of a farm. Mastitis is a costly disease, due to losses (a reduction of output due to mastitis) and expenditure (additional inputs to reduce the level of mastitis). Worldwide, published estimates of the economic losses of clinical mastitis range from ?1 to ?7 per cow on a farm, with large differences between farms, e.g. in The Netherlands, losses due to clinical and subclinical mastitis varied between ?7 and ?98 per cow per year. Moreover, farmers tended to underestimate these costs. This indicates that for a large proportion of farms there are many avoidable losses. In order to provide good support to farmers' decision-making, it is important to describe the mastitis setting not only in terms of disease, e.g. incidence of clinical mastitis, but also in monetary terms; and to make good decisions, it is necessary to provide the dairy farmer with information on the additional expenditure and reduced losses associated with alternative decisions. Six out of 18 preventive measures were shown to have a positive nett benefit, viz blanket use of dry-cow therapy, keeping cows standing after milking, back-flushing of the milk cluster after milking a cow with clinical mastitis, application of a treatment protocol, washing dirty udders, and the use of milkers' gloves. For those measures that included a large amount of routine labour or investment, the reduced losses did not outweigh the additional expenditure. The advisor cannot expect that measures that are cost-effective are always implemented. Reasons for this are the objectives of the dairy farmer can be other than maximisation of profit, resources to improve the mastitis situation compete with other fields of management, risk involved with the decision, economic behaviour of the dairy farmer, and valuation of the cost factors by the dairy farmer. For all decision-makers this means that, although financial incentives do have an effect on the management of mastitis, it is not always sufficient to show the economic benefits of improved management to induce an improvement of management of mastitis.