Infection In Dairy Cattle Research Articles

Seroprevalence survey of Aino virus infection in dairy cattle of Fukuoka, Japan in 1990.

The seroprevalence and seroconversion to Aino virus infection were epidemiologically analyzed in Fukuoka Prefecture, by a cohort study, in 1990. Serum samples (872) were taken from 436 cattle of 128 farms in five different districts at twice sampling with four month-intervals and were tested by a serum neutralizing test with Aino virus. In the first sampling (May-July), 38.3% of sera and 40.6% of farms tested were positive and 33.3% of cattle and 40.6% of farms were sero-converted during the period of September-November in 1990. Significant differences were found in seroprevalence of farms and seroconversion of cattle/farms among five districts; there was, however, a highly significant correlation between seroprevalence and seroconversion of farm. Consequently, five districts of Fukuoka Prefecture were classified into four epidemic areas according to seroprevalence and seroconversion factors of a principal component analysis.

Effect of vaccination with a recombinant Bm86 antigen preparation on natural infestations of Boophilus microplus in grazing dairy and beef pure and cross-bred cattle in Brazil

Current methods for the control of the cattle tick Boophilus microplus infestations are not effective and the parasite remains a serious problem for the cattle industry in tropical and sub-tropical areas. Recent advances have introduced the possibility for the immunological control of the parasite through the use of recombinant vaccines. Recently, it was shown that the recombinant vaccine Gavac™ (Heber Biotec S.A.) is able to control B. microplus populations in artificially infected grazing dairy cattle in Cuba. To assay the effect of the vaccine on a different B. microplus strain and under different ecological conditions, we conducted a trial in Brazil on grazing dairy and beef pure and cross-bred cattle under natural infestation conditions. A farm in the northeast of the state of Sao Paulo was selected and two groups of animals per breed were included in the experiment and were maintained grazing on separate but similar pastures. For each breed, one group was vaccinated with the vaccine Gavac and the second group was not vaccinated and was employed as a control. In vaccinated cattle, during 36 weeks of experiment, the average infestation rate was maintained below 78 ticks per animal while average infestation peaks (mean ± S.E.) of 144 ± 44 ticks per animal (for dairy cross-bred cattle) and 195 ± 42 ticks per animal (for beef cross-bred cattle) were recorded in the control groups. Tick infestation rates showed statistical significant differences ( p=0.04) between both experimental groups throughout the experiment. These results clearly showed, as in the Cuban study, that the vaccine controlled tick numbers in successive generations in the field.

Use of bovine myeloperoxidase as an indicator of mastitis in dairy cattle

Bovine myeloperoxidase (MPO) is a heme protein consisting of both large and small polypeptide subunits. In mammals the role of MPO in defending against microbes is well documented. To evaluate the potential of using MPO in the diagnosis of udder infections in dairy cattle we developed a specific enzyme immunoassay for bovine MPO in milk. Antibodies against bovine MPO were produced using the purified enzyme. The ELISA utilizes two specific antibodies: one that is anti-MPO monoclonal and one that is anti-MPO polyclonal. For a total of 141 milk samples the correlation coefficient between the somatic cell count and MPO concentrations determined using the ELISA was 0.91. The ELISA showed good precision and accuracy in measuring MPO in milk, with a total variation of ca. 10%. The recoveries of known amounts of MPO from milk were satisfactory. Thus the stability of the enzyme in milk was judged to be good. Microorganisms were isolated in ca. 85% of the milk samples with elevated concentrations of MPO. Microorganisms were not isolated from more than 90% of non mastitic milk samples with low somatic cell counts where MPO was not detectable using ELISA. The results clearly show that the quantitative analysis of the amount of MPO in mastitic milk can be used to detect intramammry infections in dairy cattle.

Salmonella dublin Infections in Cattle in California

Salmonellosis is a commonly encountered disease of cattle. Of the many serotypes of Salmonella known to exist, Salmonella typhimurium and S. dublin are the two most frequently isolated from cattle. Salmonella dublin is isolated commonly from cattle in states west of the Rocky Mountains. Reports of isolations of S. dublin from states east of the Rockies are increasing.2,4 Salmonella dublin is also isolated commonly in Europe and South Africa. Unlike S. typhimurium, which shows no special affinity for a particular host, S. dublin is host-adapted for cattle. While other animal species can be infected with S. dublin, cattle account for approximately 96% of the isolations from animals. This host-adaptation for cattle has special implications regarding epidemiology and control measures. The purpose of this presentation is to give an overview of the current spectrum of S. dublin infections in dairy cattle in California.

Diagnosis of paratuberculosis in dairy cattle, using enzyme-linked immunosorbent assay for detection of antibodies against Mycobacterium paratuberculosis in milk

Summary An elisa containing lipoarabinomannan (lam) antigen was used to detect antibodies in milk and serum for diagnosis of Mycobacterium paratuberculosis infection in dairy cattle. In experiment 1, milk and serum samples were obtained from 25 cows, and subjected to lam elisa testing immediately, and after 1 year of storage at −70 C. Milk samples, with and without a commonly used chemical preservative, were tested. There was no significant difference in lam elisa results between fresh and frozen samples or between preserved and unpreserved milk samples. In experiment 2, milk samples were collected daily from 30 cows over a 14-day period. The day-to-day coefficient of variation was 0.19 for milk lam elisa and was 0.15 for serum lam elisa, with no statistically significant time effect detected. In experiment 3, single milk, serum, and fecal samples were obtained from 764 cows. The fecal samples were cultured for M paratuberculosis to identify infected cows, and the serum and milk samples were subjected to lam elisa testing. Results were compared, using the area under the receiver operating characteristic curves. The milk lam elisa had specificity (± 95% confidence limits) of 87 ± 8.1% when the cutoff was set at 50% sensitivity, and specificity of 83 ± 9.1% when sensitivity was set at 60%. The area under the receiver operating characteristic curve was 0.85 ± 0.03 for the milk elisa and 0.75 ± 0.02 for the serum elisa. In this population of cattle, the milk lam elisa had comparable accuracy to serum lam elisa, although the milk lam elisa was slightly less reproducible (higher coefficient of variation).

Antibodies to bovine viral diarrhoea virus in beef cattle

Abstract Infection of cattle with bovine viral diarrhoea virus (BVD virus) is common throughout the world(1) and the prevalence of neutralising antibodies to the virus reported from surveys ranges from about 40% to 90%(2)(3)(4). The first isolation of BVD virus in New Zealand was reported in 1967(5) and, since that time, evidence of widespread infection in dairy cattle has been presented(6). Whilst the diseases associated with BVD viral infection have been well recognised in dairy herds, there has been a belief that infection of beef herds is less common. Based on this belief has been the fear that the growth of the dairy beef industry could lead to the introduction of BVD virus into an essentially naive beef population with disastrous results such as those reported by MacNeil and van der Oord(7). We decided therefore to sample beef cattle submitted to abattoirs throughout New Zealand for serological evidence of prior exposure to BVD virus.

Evaluation of a Dairy Herd Improvement Association test to report chronic intramammary infections in dairy cattle

This study evaluated the accuracy of a Dairy Herd Improvement Association test compared with bacterial culture to report the prevalence of chronic intramammary infections in dairy cattle. The Association classification considers a cow to have a chronic intramammary infection when her linear score is 4 or greater for more than one test in a lactation. The threshold level of linear score 6 minimized the sum of the misclassification errors. The Association test was not sensitive or specific enough compared with bacterial culture to classify individual cows accurately.

Theileria sergenti infection in dairy cattle.

[in Japanese]

Evaluation of Methods for the Diagnosis of Streptococcus agalactiae Intramammary Infections in Dairy Cattle

The sensitivity, specificity, and positive and negative predictive values were compared for six methods of collecting or culturing milk samples for the diagnosis of chronic Streptococcus agalactiae intramammary infection. Cows in four dairy herds were cultured three times in 2 wk to determine infection status. At the second sample period, individual quarter and composite milk samples were taken before and immediately after milking, and two volumes of milk from the composite samples were streaked on culture plates. The Sensitivity, specificity, and predictive values for these cultures ranged between 95 and 100% for all diagnostic methods, and no significant differences were found between methods. The results indicate that when either quarter or composite samples are collected before or immediately after milking, 95 to 100% of S. agalactiae culture-positive cows will be infected with S. agalactiae in herds with a prevalence of S. agalactiae between 35 and 55%. A similar proportion of culture-negative cows will be uninfected.

A cross-sectional study of bluetongue virus and Mycoplasma bovis infections in dairy cattle: I. the association between a positive antibody response and production efficiency

In a cross-sectional study of bluetongue virus (BTV) and Mycoplasma bovis (M. bovis) infections, a sample of 572 California dairy cows was tested for the presence of antibodies to answer the question: Is it possible to identify and to assess quantitatively the associations between positive antibody test and production? Serum samples collected from these cows during December 1986 were tested for the presence of antibodies to BTV and M. bovis using the enzyme-linked immunosorbent assay (ELISA). Data on milk production were extracted from individual cow sheets of the California Dairy Herd Improvement Association (DHIA) record-keeping system and interfaced with percentage ELISA results for analysis. Univariate and multivariate statistical analyses, using the chi 2 test for categorical variables or Student's t-test for continuous variables and multiple logistic regression respectively, were carried out to evaluate for possible associations between positive antibody tests to each agent and each production variable of interest. Complete data on all variables studied were obtained for 289 (50.5%) cows for M. bovis and 423 (74%) cows for BTV. For cows with complete data on all variables, estimates of the point prevalence of antibodies to BTV and M. bovis were 70.5% and 66.1%, respectively. Results of this study indicated that Guernsey cows were more likely to have a positive BTV test than Holstein cows and that cows in higher lactations were more likely to test positive to BTV ELISA than those in lower lactations (p less than 0.05). Because all cows except those on one farm were Holstein, our confidence in the effect of breed is limited. The association between lactation number and BTV seropositive test may be an age factor identified earlier in the study. For M. bovis, the results of the analysis indicated that seropositive cows were more likely to produce less milk, on a mature equivalent basis (ORadj = 0.96, p = 0.034), and that they had less extended 305 day milk production potential (ORadj = 0.90, p less than 0.0001) than seronegative cows.

A cross-sectional study of bluetongue virus and Mycoplasma bovis infections in dairy cattle: II. The association between a positive antibody response and reproduction performance

In a cross-sectional study to determine the possible relationship between a positive antibody test to bluetongue virus (BTV) or Mycoplasma bovis infections and reproductive performance of dairy cows, data were collected on 572 California dairy cows during December 1986 for analysis. Serum samples were tested using an enzyme-linked immunosorbent assay (ELISA). Data on reproduction variables were extracted from the individual cow sheets of the California Dairy Herd Improvement Association records and interfaced with the serological results for analysis. Similar data analyses for both BTV and M. bovis were performed to identify and quantitatively assess the association of the reproduction variables and each agent. These associations were evaluated unconditionally using the chi 2 for categorical variables and Student's t-test for continuous variables. Logistic regression analysis was used to determine if reproduction variables with significant unconditional associations remained significant when adjusted for the effects of possible confounding factors. Both the BTV and M. bovis ELISA antibody titres indicated exposure to the agents. The results of the multiple logistic regression analyses indicated that cows seropositive for BTV were significantly older at first calving (p less than 0.03). For M. bovis, seropositive cows were more likely to have longer intervals from calving to last service and longer intervals from calving to pregnancy diagnosis than seronegative cows (p less than 0.05). The other reproduction variables examined were not significantly associated with ELISA seropositivity.

Seasonal prevalence of thermophilicCampylobacterinfections in dairy cattle and a study of infection of sheep

A total of 273 rectal swabs from dairy cows were cultured for Campylobacter jejuni/coli. The isolation rate was 17/72 (24%), 33/106 (31%) and 11/95 (12%) during summer, autumn and winter respectively. Approximately half of the isolates were C. jejuni and the other half C. coli. The isolates recovered from dairy cows were typed by bacterial restriction endonuclease DNA analysis (BRENDA) and compared with those of sheep. Seventeen different BRENDA patterns were produced by the isolates from dairy cows and six from 27 isolates of sheep. Of these 21 different BRENDA patterns only two were common to sheep and cattle.

Possible role of leptospires of the Pomona serogroup in sporadic bovine abortion in the south west of England.

An investigation of a small outbreak of abortion in mixed-age cows in a dairy herd in Somerset produced circumstantial evidence that a leptospire belonging to the Pomona serogroup was the causative agent. Although the initial epidemic involved more than 30 per cent of the herd, agglutination titres did not persist in the majority of animals and bacteriological monitoring produced no evidence that this leptospire could establish endemic infection in dairy cattle. An isolate recovered from the kidney of a cow which aborted was found to be similar to mozdok, a serovar maintained by free-living species in continental Europe, and it is probable that free-living species also maintain the Pomona serogroup organisms that have been isolated in England. Clinical disease caused by infection of domestic stock with Pomona serogroup organisms other than pomona has not been recognised in other countries but this may be because of the presence of endemic infection with pomona, a serovar that causes a very similar clinical and serological response.

Leptospirosis: I. Clinical investigation of the infection in dairy cattle in the Waikato district of New Zealand

An investigation was made into the prevalence of leptospiral infection in cattle. An area 50 km radius was selected in a region where leptospirosis was reputedly common. Farmers volunteered 250 herds with 39 500 cows for testing and 7 500 animals were selected and sampled. Twenty-nine cows (0.4%) on 14 (5.6%) of the farms had leptospiruria at the first examination. Leptospirae were cultured from the urines of nine of these animals and all were Leptospira interrogans serovar hardjo. Serologically 12.5% of cows had titres of 1:200 or greater to hardjo and 3.5% titres of 1:200 or greater to pomona. In the Spring of 1977, there was evidence of clinical leptospirosis in calves associated with only one of the herds and no clinical leptospirosis in the 250 lactating herds, although leptospiral titres were found in 88% of them. This indicated that clinical disease was much less common than infection. We concluded that leptospirosis was of minor economic importance in dairy cattle, although it could be significant in individual herds, and a health hazard to farm workers.

A Working Model for the Evaluation of Different Immunological Traits as Indicators of Resistance to Infection in Dairy Cattle

In order to determine the relative value of different immunological traits as indicators of resistance to infection, an analysis was performed based on records of immunological traits in young bulls and “health card” records of clinical mastitis in their half sisters. The correlation analysis suggested that young bulls with high levels of serum immunoglobulin have half sisters with low mastitis frequency. A significant positive correlation was found between the antibody response peak against human serum albumin and susceptibility to mastitis. The results of this analysis should not be considered conclusive as the data were limited. Further work is required on a larger body of material. The model described here may be considered for future use as it enables immediate selection of animals.

Acute Trypanosoma vivax infection in dairy cattle in Coast Province, Kenya.

In an outbreak of a fatal haemorrhagic disease in exotic dairy cattle (Friesian, Guernsey, Ayrshire and Jersey) on 2 farms in the Coast Province of Kenya, and investigation was conducted to establish the aetiological agent involved. Blood and lymph node smears made from clinically sick cattle indicated infection with Trypanosoma vivax. Five calves were then experimentally inoculated with heparinised blood from cows naturally infected with T. vivax. All calves had a high T. vivax parasitemia, marked depression and fever; 2 developed blood-tinged diarrhoea 6 and 7 days were treated with isometamidium chloride while others were left untreated. Cases of abortions, bloody diarrhoea and deaths dropped markedly in the treated animals whereas they continued to occur in the untreated animal.

LEPTOSPIRA INTERROGANS SEROVAR HARDJO INFECTION OF CATTLE

A survey of normal cattle in the Southern Victorian statistical divisions revealed that microscopic agglutination titres to L. hardjo occur at high frequency and are distributed throughout the cattle population. These titres are difficult to interpret as they may represent recent or old exposure, with or without disease. L. hardjo infection of dairy cattle was studied in 4 herds using the microscopic agglutination and complement-fixation tests. Statistical comparisons of individual titres obtained indicated that the sensitivity of the complement-fixation test was satisfactory for diagnostic purposes, but the test was unable to differentiate between current or past infections.

The Role of Dairy Cattle in the Epidemiology of Q Fever in Idaho

As a result of comprehensive studies of Q fever in southern California, the disease in man was shown to be associated with infected dairy cattle (Beck et al, 1949; Bell et al, 1950). Seropositive cows were found to eliminate C. burnetii in their milk and placentas but the latter was considered to be the chief source of environmental contamination (Huebner et al, 1948; Luoto and Huebner, 1950). Direct occupational contact with infected dairy cattle or their raw products, residence near contaminated premises, and household use of raw milk

Brucella Abortus Infection in Dairy Cattle in Singapore

Brucella Abortus Infection in Dairy Cattle in Singapore