Lack of risk of transmission of caprine arthritis-encephalitis virus (CAEV) after an appropriate embryo transfer procedure

The aim of this study was to demonstrate that embryo transfer can be used to produce CAEV-free kids from CAEV-infected biological mothers when appropriate procedure is implemented. Twenty-eight goats that had tested positive for CAEV using PCR on vaginal secretions were used as embryo donors. Embryos with intact-ZP were selected and washed 10 times; they were then frozen and used for transfer into CAEV-free recipient goats. Nineteen of the 49 recipient goats gave birth, producing a total of 23 kids. Three blood samples were taken from each recipient goat, 10 days before, during, and 10 days after parturition; these were tested for CAEV antibodies using ELISA and for CAEV proviral DNA using PCR. The mothers were then euthanized. Tissue samples were taken from the lungs, udder, and retromammary and prescapular lymph nodes. The kids were separated from their mothers at birth. Seven of them died. At 4 months of age, 16 kids were subjected to drug-induced immunosuppression. Blood samples were taken every month from birth to 4 months of age; samples were then taken on days 15, 21, and 28 after the start of the immunosuppressive treatment. The kids were then euthanized and tissue samples taken from the carpal synovial membrane, lung tissue, prescapular lymph nodes, inguinal and retromammary lymph nodes, and uterus. All samples from the 19 recipient goats and 23 kids were found to be negative for CAEV antibodies and/or CAEV proviral DNA. Under acute conditions for infection this study clearly demonstrates that embryo transfer can be safely used to produce CAEV-free neonates from infected CAEV donors.     

Epidemiological studies on caprine arthritis-encephalitis virus infection in Jordan

To investigate the seroprevalence of, and risk factors for, caprine arthritis-encephalitis virus (CAEV) infection in different breeds of goats in Jordan, sera from 1100 goats from three different geographical regions in Jordan were analyzed. Prevalence of antibodies to CAEV was determined using a competitive ELISA test. A semi-structured questionnaire was used to collect information on herd health and management. Questionnaire data were tested in a multivariable logistic regression model to elucidate risk factors associated with CAEV seropositivity. In addition, the incidence of CAEV antibodies was investigated in six goat herds located in the northern part of Jordan. Out of the 69 goat herds investigated, 16 (23.2%) had antibodies against CAEV. Individual goat true seroprevalence to CAEV was 8.9%. The highest CAEV seroprevalence was observed in goats older than 3-years and younger than 6-years of age. The seroprevalence of CAEV in goats was significantly higher (P < 0.05) in the northern part of Jordan than that in central or southern parts of Jordan. The multivariable logistic regression model identified large herd size (OD = 2.0; 95% CI: 1.1, 2.7), addition of new animals to the herd (OD = 1.3; 95% CI: 0.3, 1.6) and contact with other goat herds (OD = 1.1; 95% CI: 0.9, 2.0) as risk factors for CAEV seropositivity. The incidence of CAEV seropositivity in the six herds monitored in the northern part of Jordan ranged from 2.4 to 5.3%.     

Surveillance of Mycoplasma agalactiae and Mycoplasma mycoides subsp. capri in dairy goat herds

This study was designed to monitor the presence of Mycoplasma agalactiae and Mycoplasma mycoides subsp. capri (Mmc) in 66 dairy goat herds of a genetic improvement programme in a region of Spain where contagious agalactia is endemic. Over a whole lactation period, 300 bulk tank milk and 381 milk samples from goats with clinical mastitis were subjected to polymerase chain reaction (PCR) to detect the two mycoplasma species. The presence of mycoplasmas (either species or both) was detected in 66.7% of the herds and M. agalactiae was identified in 95.45% of these positives herds. In a given infected herd, mycoplasmas were not continuously detected over the whole study period. Our findings indicate that in an endemic area, M. agalactiae and Mmc can be monitored through PCR analysis of mastitic milk and bulk tank milk (BTM) samples. Over a lactation period we recommend testing multiple BTM samples on a herd. No relationship was observed between the use of inactivated mycoplasma vaccines and the PCR detection of both mycoplasmas.     

Presence of caprine arthritis-encephalitis virus (CAEV) infected cells in flushing media following oviductal-stage embryo collection

To improve the knowledge on the risk of transmission of the caprine arthritis-encephalitis virus (CAEV) during embryo manipulations, we conducted a double-nested polymerase chain reaction (PCR) for CAEV proviral-DNA on flushing media recovered from the oviducts 48 h after the beginning of estrus and on blood from 89 donor does. Sixty-four does had negative blood and flushing media by PCR. Among the 25 CAEV infected goats (blood PCR positive), 11 were PCR flushing media positive (P < 0.01). Cell lysate from flushing media samples that were PCR positive were serially diluted 10 times at 1:100. Starting with the second 1:100 dilution all the cell lysate samples were PCR negative. The mean number of embryos recovered was not significantly different between goats with flushing media PCR positive and goats with flushing media PCR negative (6.0 +/- 5.4 versus 7.8 +/- 4.4, respectively; mean +/- S.D.) nor between goats with blood PCR positive and goats with blood PCR negative (7.0 +/- 5.0 versus 5.9 +/- 5.3; mean +/- S.D.). The presence of CAEV infected cells in oviductal flushing media from infected donor does was indicated for the first time during this study. The absence of flushing media PCR positive for goat blood PCR negative seemed to allow the use of the blood PCR test to confidently predict the absence of CAEV provirus in the oviductal fluid.     

Reproductive Failure in Goats in Norway: An Investigation in 24 Herds

Twenty-four flocks comprising 2370 breeding goats were examined. Threehundred-and-sixty-nine (15.6 %) of the goats either aborted or delivered dead kids at full term, or were barren. In 23 of the herds the rate of reproductive loss ranged from 2 % to 36 %, whereas in one herd all of 54 mated goats had live kids. A loss of ≥ 20 % was found in 9 herds comprising 799 goats. In 11 herds comprising 946 goats the rate of reproductive failure was ≤ 10 %. The incidence of reproductive failure was higher in older goats than in those in their first or second pregnancy. The causes were identified in only about 3 % of the goats that aborted. It is concluded that reproductive failure in many flocks probably is associated with non-infectious causes such as nutritional and environmental factors.     

Mycobacterium avium subspecies paratuberculosis cultured from locally and commercially pasteurized cow's milk in the Czech Republic

Between November 2002 and April 2003, 244 bottles and cartons of commercially pasteurized cow's milk were obtained at random from retail outlets throughout the Czech Republic. During the same period, samples of raw milk and of milk that was subsequently subjected to a minimum of 71.7 degrees C for 15 s in a local pasteurization unit were also obtained from two dairy herds, designated herds A and B, with low and high levels, respectively, of subclinical Mycobacterium avium subsp. paratuberculosis infection, and from one herd, herd C, without infection. Infection in individual cows in each herd was tested by fecal culturing. Milk samples were brought to the Veterinary Research Institute in Brno, Czech Republic, processed, inoculated onto Herrold's egg yolk slants, and incubated for 32 weeks. Colonies were characterized by morphology, Ziehl-Neelsen staining, mycobactin J dependency, and IS900 PCR results. M. avium subsp. paratuberculosis was cultured from 4 of 244 units (1.6%) of commercially pasteurized retail milk. M. avium subsp. paratuberculosis was also cultured from 2 of 100 (2%) cartons of locally pasteurized milk derived from infected herds A and B and from 0 of 100 cartons of milk from uninfected herd C. Raw milk from 1 of 10 (10%) fecal culture-positive cows in herd A and from 13 of 66 (19.7%) fecal culture-positive cows in herd B was culture positive for M. avium subsp. paratuberculosis. These findings confirm that M. avium subsp. paratuberculosis is present in raw milk from subclinically infected dairy cows. The culture of M. avium subsp. paratuberculosis in the Czech Republic from retail milk that had been pasteurized locally or commercially to the required national and European Union standards is in agreement with similar research on milk destined for consumers in the United Kingdom and the United States and shows that humans are being exposed to this chronic enteric pathogen by this route.     

Comparative age-related responses to serological and faecal tests directed to Mycobacterium avium paratuberculosis (Map) in French dairy goats

The objectives of the present study were to estimate sensitivity and specificity of 6 different tests directed to Mycobacterium avium paratuberculosis (faecal culture, microscopic examination, Agar Gel Immunodiffusion (AGID) and 3 commercial ELISA tests, named A, B and C) in different age categories and to assess the degree of agreement between responses thus obtained. The study was carried out in 12 French commercial dairy herds, which were selected in a population of herds with unknown paratuberculosis status. In each herd, a sample of goats without clinical signs was randomly selected according to 4 age categories. Responses of 412 goats with concomitant results for the 6 tests were analysed. In the 4 age categories, the specificity and the sensitivity of the 6 tests were estimated using Bayesian methods with conditional dependence between tests. Agreement among the results obtained for these tests was determined by calculating the kappa statistic.With the exception of AGID, the proportions of positive responses for each test differed significantly between herds (range 0–27.5%). With the exception of scopy, the proportions of positive responses for each test differed significantly between age categories. Sensitivities and specificities of the 6 tests were very different according to age categories. Specificities were higher than sensitivities. The highest values in sensitivity were obtained in goats between 2 and 3 years, with the best value for ELISA C (76.6%, 95% CI of 46.1–96.1%). In the other age categories, sensitivities of the 6 tests were too low to have practical use. Only scopy, faecal culture and ELISA B have positive responses in category 1 (goats of less than 1 year). Agreements between the different pairs of tests were low, except between the 3 ELISA tests which were in “good” or “quite good” agreement.This study showed that detection of infection with Map was efficient only in goats between 2 and 3 years, with an ELISA test. For goats in other age categories, no test was sensitive enough to detect goats infected with Map. In a Map infection control program, ELISA tests, performed on goats between 2 and 3 years, can be used to define herd status and to estimate prevalence but they should not be used at goat level to select goats for culling, due to the low positive predictive value.     

Corynebacterium Pseudotuberculosis Infection in Goats III.

Serological examinations for Gorynebacterium pseudotuberculosis in-fection were carried out in 14 known positive herds and in 1 herd that had beeni recently established through purchase of animals from different herds. Serum samples were collected sequentially on up to 4 occasions from animals during their first year of life. In most herds, these animals were examined clinically for superficial swellings once or twice during the same period. The adult goats in 8 infected herds were examined both clinically and serologically. Age distribution was similar in each of these herds. All serum samples were examined for antibodies against Gorynebac-terium pseudotuberculosis in both the bacterial agglutination test (BAT) and the hemolysis inhibition test (HIT). The proportion of kids which were seropositive in both tests de-creased to zero at 4 months of age. At the age of 11–12 months, the proportion of seropositive animals was about 50 % in the BAT and 30 % in the HIT. When examined when housed for the winter at the age of about 8 months (mean age), the prevalence of animals with superficial swellings was 7 %. At the age of about 1 year (mean age), 29 % of the examined animals had such lesions. In the recently established herd, only a few of the yearlings were seropositive. Titre values in BAT and HIT increased until 6 years of age. Anti-body titre values were significantly lower in yearlings than in older goats in both tests, P < 0.005. No significant difference in the propor-tion of goats with superficial swellings was seen at the different ages.     

The feral goats of Kielderhead Moor

Herds of feral goats are present along the high ground of the Scottish Borders at the College, Hindhope, Kielderhead Moor (the study area), Bewcastle Fell and Roan Fell.
In the study area the nannies remained solitary, or in the company of their yearlings on the steep ground below the high moor throughout the winter. After the birth of their kids in March two female herds were formed each with a herd billy which came from the two male herds which were present through the winter on the high moor. The male herds left the study area in the spring and their ranges are not known. The two female herds maintained separate ranges on the high moor until the end of August when they combined into one large herd and were joined by a strange herd of billies which had not previously been seen.
After the first three or four days of its life the kid is left in a hiding place for most of the day whilst its mother ranges widely grazing with the herd. The kids join the herd when they are about six weeks old.
The Kielderhead Moor goats had a recruitment rate of 0–29/nanny/year and the females have a further expectation of life of 3–7 years. Figures for the billies are unreliable as disappearances of males from the moor are more likely to be the result of emigration than of deaths. While the herds of nannies have fairly restricted home ranges there is some evidence to suggest that many of the billies wander freely along the Borders.
In the early part of the summer the sheep and goats are eating very similar proportions of the plants present on the moor. Later on in the season there is a divergence with the sheep eating less Calluna while the goats eat less Eriophorum , but as the Trichophorum becomes available both animals include this in their diet.     

Study on Passive Immunity:time of Vaccination in Kids Born to Goats Vaccinated Against Peste des petits ruminants

In this study,the decay of maternal peste des petits ruminants virus(PPRV) antibodies in kids born to goats vaccinated with Asian lineage IV PPR vaccine and the efficacy of passive immunity against PPRV was assessed to determine the appropriate period for vaccination in kids.Serum samples collected from kids born to vaccinated,unvaccinated and infected goats at different time intervals were tested by PPR competitive ELISA and serum neutralization test(SNT).Maternal antibodies in kids were detectable up to 6 months with a decline trend from the third month onwards and receded below the protective level by the fourth month.The kid with an SN titre of 1:8 at the time of immunization showed significant PPRV specific antibody response(percentage inhibition of 76;SN titers >1:16),when tested on 21 day post-vaccination and was completely protected from infection upon virulent PPRV challenge.Similarly,the kid with 1:8 SN titers was completely protected from PPR infection on active challenge.Therefore,PPR vaccination is recommended in kids,aged 4 months and born to immunized or exposed goats.This could be a suitable period to avoid window of susceptibility in kids to PPRV and the effort to eliminate PPR infection from susceptible populations.     

Mycobacterium avium Subspecies paratuberculosis Cultured from Locally and Commercially Pasteurized Cow's Milk in the Czech Republic

Between November 2002 and April 2003, 244 bottles and cartons of commercially pasteurized cow's milk were obtained at random from retail outlets throughout the Czech Republic. During the same period, samples of raw milk and of milk that was subsequently subjected to a minimum of 71.7°C for 15 s in a local pasteurization unit were also obtained from two dairy herds, designated herds A and B, with low and high levels, respectively, of subclinical Mycobacterium avium subsp. paratuberculosis infection, and from one herd, herd C, without infection. Infection in individual cows in each herd was tested by fecal culturing. Milk samples were brought to the Veterinary Research Institute in Brno, Czech Republic, processed, inoculated onto Herrold's egg yolk slants, and incubated for 32 weeks. Colonies were characterized by morphology, Ziehl-Neelsen staining, mycobactin J dependency, and IS900 PCR results. M. avium subsp. paratuberculosis was cultured from 4 of 244 units (1.6%) of commercially pasteurized retail milk. M. avium subsp. paratuberculosis was also cultured from 2 of 100 (2%) cartons of locally pasteurized milk derived from infected herds A and B and from 0 of 100 cartons of milk from uninfected herd C. Raw milk from 1 of 10 (10%) fecal culture-positive cows in herd A and from 13 of 66 (19.7%) fecal culture-positive cows in herd B was culture positive for M. avium subsp. paratuberculosis. These findings confirm that M. avium subsp. paratuberculosis is present in raw milk from subclinically infected dairy cows. The culture of M. avium subsp. paratuberculosis in the Czech Republic from retail milk that had been pasteurized locally or commercially to the required national and European Union standards is in agreement with similar research on milk destined for consumers in the United Kingdom and the United States and shows that humans are being exposed to this chronic enteric pathogen by this route.     

Study on passive immunity: Time of vaccination in kids born to goats vaccinated against Peste des petits ruminants

In this study, the decay of maternal peste des petits ruminants virus (PPRV) antibodies in kids born to goats vaccinated with Asian lineage IV PPR vaccine and the efficacy of passive immunity against PPRV was assessed to determine the appropriate period for vaccination in kids. Serum samples collected from kids born to vaccinated, unvaccinated and infected goats at different time intervals were tested by PPR competitive ELISA and serum neutralization test (SNT). Maternal antibodies in kids were detectable up to 6 months with a decline trend from the third month onwards and receded below the protective level by the fourth month. The kid with an SN titre of 1:8 at the time of immunization showed significant PPRV specific antibody response (percentage inhibition of 76; SN titers >1:16), when tested on 21 day post-vaccination and was completely protected from infection upon virulent PPRV challenge. Similarly, the kid with 1:8 SN titers was completely protected from PPR infection on active challenge. Therefore, PPR vaccination is recommended in kids, aged 4 months and born to immunized or exposed goats. This could be a suitable period to avoid window of susceptibility in kids to PPRV and the effort to eliminate PPR infection from susceptible populations.     

Presence of caprine arthritis-encephalitis virus (CAEV) proviral DNA in genital tract tissues of superovulated dairy goat does

Transmission of caprine arthritis-encephalitis virus (CAEV) is not completely understood and the vertical route of infection from the goat to the embryo or to the fetus needs to be investigated. This route of infection involves the presence of CAEV in the genital tract tissues. Prior studies have detected CAEV-infected cells in genital secretions and in flushing media recovered during embryo collection from infected goats. To specify the origin of these cells, we conducted a double-nested polymerase chain reaction (PCR) test on embryo flushing media and on mammary gland, mammary lymph node, synovial membrane, pelvic lymph node, uterus and oviduct tissues from 25 CAEV-infected (blood PCR positive) embryo donor goats for the presence of CAEV proviral DNA.The presence of proviral DNA was found in 22 of 25 mammary gland samples, 14 of 25 uterus samples, and in 16 of 25 oviduct samples. Nineteen of 25 goats had at least one positive genital tract sample. Flushing media from 11 goats were PCR positive. All goats with positive-flushing media were oviduct positive. Of this group of does, except for 1 of the 11, infection of flushing media correlated with infection of almost all the other tissues examined. The frequency of positive tissues for flushing media-positive goats (61/66; 92%) was significantly higher than that for flushing media-negative goats (50/84; 60%) (P<0.01).This study demonstrated the presence of CAEV-infected cells in the goat genital tract. The presence of CAEV-infected cells in the uterus and oviducts suggests potential for vertical transmission of CAEV from doe to embryo or fetus.     

Evaluation of a contract breeding management program in Ohio dairy herds: test day summary and economic measures

A field study was conducted to assess the impact of a contract breeding program that was offered by a breeding co-operative and featured tail chalking and daily evaluation of cows for insemination by co-operative technicians; dairy employees no longer handled estrous detection and insemination activities. From early 2002 until mid-2004, herd-level test day summary records related to production and reproduction were obtained for 32 herds identified as well-managed client herds of the breeding co-operative. Using analyses that controlled for other predictors and random herd-level effects, average days to first service were less by 13 days (P=0.0037) and estrous detection rate was greater by 12% (P=0.0011) for program than for non-program herds. Although first service conception rate was slightly less and the program herds used 0.34 more services per conception (P=0.1488) than non-program herds, the program herds averaged 16 fewer days before pregnancy (P=0.028). Test day summary information and representative estimates of feed, milk, and semen prices were used in a spreadsheet-based model to estimate a partial budget annuity value for an average cow in each herd on each test day. Value of an average cow from a contract herd did not significantly differ from a non-contract herd, even though the analyses suggested an economic benefit for the program herds; the modeling did not, however, account for costs of the program implementation. Additional analyses did not find any significant associations between technician and on days to first service, first service conception rate, estrous detection rate, services per conception, or days open.     

Prevalence and risk factors of caprine arthritis encephalitis virus infection (CAEV) in Northern Somalia

The aim of the present study was to determine seroprevalence and the risk factors associated with caprine arthritis encephalitis virus infection (CAEV) in Northern Somalia (Somaliland). A total of 1198 serum samples were collected from 34 randomly selected goat herds of two major districts of Somaliland namely, Togdheer (Burao) and Waqoyi Galbed (Hergiesa). Serum samples were examined for CAEV antibodies using competitive enzyme linked immunosorbent assay (cELISA). A total of 72 goats were found seropositive with overall seroprevalence of 6.0%. On animal level, multivariate logistic regression showed that there was a significant association between CAEV infection and age (P < 0.01; OR: 16.282; CI 95%, 5.87–25.17), rearing with sheep (P < 0.001; OR: 4.158; CI 95%, 1.47–11.715), and herd size (P < 0.05; OR: 1.22; CI 95%, 0.93–2.17). However, on the herd level, herd size (P < 0.05; OR: 1.96; CI 95%, 0.51–1.76) and rearing with sheep (P < 0.05; OR: 13.31; CI 95%, 1.30–13.24) were the risk factors.The result of the present study indicates that CAEV infection exists in the goat herds in Somaliland. It also provides an overview about the risk factors associated with the disease at the examined localities.     

Social hierarchy in the domestic goat: effect on food habits and production

Outside the scientific world, the effect of social behaviour on production is little taken into account, but the importance of this relationship has been sufficiently proven in some animal species. Nevertheless, there are scarce works that emphasise the importance of behaviour in the production of the goat. The main objective of this paper is to determine if there is a stable hierarchy of dominance in a flock of goats fed in pasture, and if this hierarchy influences somehow the diet selected in the pasture and in its production of milk and meat. The study was carried out in a flock of goats in semi-extensive grazing management. The interactions observed in the pasture during the supplementary feeding and during the milking were written down. This allowed us to determine the dominance rank. The diet was determined in the pasture by the direct observation method. The production of milk was measured daily. The meat production consisted on the weight of the kids in their first day of life and after a month. Among the most prominent results, the following should be indicated: (a) Within the herd, a clearly established, quite stable and linear hierarchic order exists. (b) The most aggressive animals are those that occupy the highest positions within the social hierarchy. (c) Age, large size and horns seem to be the physical factors that most favor dominance. (d) When more forage becomes available, differences appear in the diet chosen by dominant and subordinate animals, that is, they become more selective. In the months of greater shortage, these differences in feeding disappear, and they become more generalist. (e) The production of animals is affected by dominance. However, contrary to what might otherwise be thought, it is the middle range of goats that are the most productive.     

Effects of an experimental Trypanosoma congolense infection on the reproductive performance of West African Dwarf goats

Thirty-six West African Dwarf (WAD) goats were used to assess the effects of an experimental Trypanosoma congolense infection on their reproductive system. Estrous cycles were synchronised and when confirmed pregnant (n = 31), the does were randomly allocated into control and trypanosome-infected groups. After infection, the animals were carefully observed till parturition. Trypanosome infection caused an increase of rectal temperature, a significant drop in PCV (infected: 23.3 +/- 0.3%; control: 28.5 +/- 0.4%; P < 0.0001) and abortions in 27.8% of the infected does. Kids born from infected does had a lower birth weight than kids born from control goats (0.9 +/- 0.1 kg versus 1.6 +/- 0.1 kg; P < 0.0001). Eight out of 13 kids (61.5%) that were born alive from infected does died during their first week of life. Plasma pregnancy-associated glycoprotein (PAG) and progesterone concentrations were lower in the infected animals than in the controls. In general, PAG concentration in does which aborted dropped before abortion. Our results revealed that artificial T. congolense infection affected reproductive performance of WAD goats with abortions, premature births and perinatal losses being observed. Neither transplacental transmission of T. congolense nor histopathological lesions of the placenta could be demonstrated.     

Evaluation of Two PCR Tests for Coxiella burnetii Detection in Dairy Cattle Farms Using Latent Class Analysis

Different tests performed on bulk tank milk samples (BTM) are available to determine the C. burnetii status of herds. However, these tests, which are based on the detection of either antibodies directed against C. burnetii (ELISA) or bacterial DNA (PCR), have limitations. A currently disease-free herd infected in the past may continue to test positive with ELISA due to the persistence of antibodies in animals that were infected and that subsequently cleared the infection. Infectious herds can also be misclassified using PCR because of the absence of bacteria in the BTM when the test is performed. Recently, PCR has been used for bacterial DNA detection in the farm environment, which constitutes the main reservoir of C. burnetii. The objectives of this study were to assess and compare the sensitivities and specificities of one commonly used PCR test in BTM (PCR BTM) and of a PCR applied to environmental samples (PCR DUST) in dairy cattle farms. BTM and dust samples were collected (using environmental swabs) in 95 herds. The evaluation of the performance of the 2 tests was conducted using latent class models accounting for within herd disease dynamics. Parameter estimation was carried out using MCMC, within a Bayesian framework. Two types of priors were used for the specificity of PCR DUST. A model with a uniform prior on 0–1 fitted the data better than a model with a uniform prior on 0.95–1. With the best model PCR DUST had a lower sensitivity than PCR BTM (0.75 versus 0.83) and a specificity of 0.72. The moderately low value for the specificity of PCR DUST suggests that the presence of bacteria on farm is not always associated with persistent infections and shedding of bacteria in milk.     

A robust method for bacterial lysis and DNA purification to be used with real-time PCR for detection of Mycobacterium avium subsp. paratuberculosis in milk

A possible mode of transmission for the ruminant pathogen Mycobacterium avium subsp. paratuberculosis (MAP) from cattle to humans is via milk and dairy products. Although controversially, MAP has been suggested as the causative agent of Crohn's disease and its presence in consumers' milk might be of concern. A method to detect MAP in milk with real-time PCR was developed for screening of bulk tank milk. Pellet and cream fractions of milk were pooled and subjected to enzymatic digestion and mechanical disruption and the DNA was extracted by automated magnetic bead separation. The analytical sensitivity was assessed to 100 organisms per ml milk (corresponding to 1-10 CFU per ml) for samples of 10 ml. The method was applied in a study of 56 dairy herds to compare PCR of farm bulk tank milk to culture of environmental faecal samples for detection of MAP in the herds. In this study, 68% of the herds were positive by environmental culture, while 30% were positive by milk PCR. Results indicate that although MAP may be shed into milk or transferred to milk by faecal contamination, it will probably occur in low numbers in the bulk tank milk due to dilution as well as general milking hygiene measures. The concentration of MAP can therefore be assumed to often fall below the detection limit. Thus, PCR detection of MAP in milk would be more useful for control of MAP presence in milk, in order to avoid transfer to humans, than for herd prevalence testing. It could also be of value in assessing human exposure to MAP via milk consumption. Quantification results also suggest that the level of MAP in the bulk tank milk of the studied Danish dairy herds was low, despite environmental isolation of MAP from the herds.