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Biomedical subjects

B Poutrel

Publications and source records attributed to B Poutrel.

At least 73 records · Page 4Linked to original sources
PubMed1983

Physiological and pathological factors influencing bovine serum albumin content of milk.

Concentrations of albumin from bovine blood serum were measured by radial immunodiffusion of 480 milk samples. Content in milk was not affected by content in serum, lactation number, or location of quarters. Bovine serum albumin concentrations in milk increased at the end of lactation (270 days) compared to the beginning (30 days) and at midlactation (150 days). Uninfected quarters had a mean concentration of serum albumin of .193 mg/ml. This was less than means for quarters infected by minor pathogens (.242 mg/ml) and by major pathogens (.284 mg/ml). Distributions of concentrations related to infection status, however, overlapped substantially. Somatic cell count was correlated .53 with concentrations of blood serum albumin in milk. About 32% of quarters infected by major pathogens had fewer than 500 x 10(3) cells/ml, whereas 47.5% of them had serum albumin content less than .2 mg/ml. For subclinical infections, concentration of serum albumin markedly increased when somatic cells were more than 1,000 x 10(3) cells/ml.

Animals↗
PubMed1983

Physiological and pathological factors influencing bovine immunoglobulin G1 concentration in milk.

Bovine immunoglobulin G1 concentration was determined by radial immunodiffusion in 349 milk samples of uninfected quarters, 95 of infected quarters, and 118 blood serum samples from 42 Holstein-Friesian cows taken at days 30, 150, and 270. In lactation, immunoglobulin G1 concentration in milk was not affected by immunoglobulin G1 concentration in blood serum or location of quarters. The immunoglobulin G1 concentrations increased at the end of lactation and in samples collected from cows beyond the third lactation. Uninfected quarters had a mean immunoglobulin G1 concentration of .46 mg/ml. This was less than means from quarters infected by minor or major pathogens. Quarter infection by Staphylococcus aureus resulted in an increase of immunoglobulin G1 concentration in blood serum (9.22 to 11.3 mg/ml). When Corynebacterium bovis was persistent throughout the lactation, immunoglobulin G1 concentration in blood serum was increased (11.26 mg/ml). There was no correlation between somatic cell count and immunoglobulin G1 concentration in uninfected quarters. There was a slight correlation between bovine serum albumin and immunoglobulin G1 concentration in identical quarters (.23). Infection of quarters increased in varying degrees the correlation between immunoglobulin G1 concentration and bovine serum albumin concentration or somatic cell count in milk.

Animals↗
PubMed1983

Cell content of goat milk: California mastitis test, Coulter counter , and fossomatic for predicting half infection.

The mean cell count of goat milk collected in early and midlactation from udder halves free of infection was 1404 X 10(3) cells/ml and 614 X 10(3) cells/ml estimated by Coulter Counter and Fossomatic. Arithmetic means of cell count by Fossomatic method for samples within California Mastitis Test scores were similar to results from cow milk. Results by the three methods were closely correlated .7. Means of cell counts were 2858 X 10(3) cells/ml and 1293 X 10(3) cells/ml by Coulter Counter and Fossomatic methods for udder halves harboring coagulase-negative staphylococci and 8946 X 10(3) cells/ml and 4804 X 10(3) cells/ml for halves infected by major pathogens. Of the thresholds examined, 1000 X 10(3) cells/ml was most satisfactory for both Coulter Counter and Fossomatic methods, because it detected about 80% of major infections and gave an acceptable proportion of errors.

Animals↗
PubMed1983

Comparative evaluation of commercial latex agglutination and coagglutination reagents for groups B, C, and D mastitis streptococci.

A total of 144 strains of mastitis streptococci (groups B, C, and D) were grouped by conventional technique (Lancefield precipitin test) latex agglutination (LA), and coagglutination (CA). The LA correctly grouped 98% and the CA grouped 100% of strains on the test when the instructions of the manufacturers were followed. Sensitivity of both tests was improved for strains belonging to group D when extracts from colonies grown on sheep blood agar plates were used for grouping. Nonspecific reactions between groups C and B were observed only with one kit of LA reagents, whereas cross-reactions were recorded with all groups when CA reagents were used.

Agglutination Tests↗
PubMed1983

[Attempts at preventing experimental Staphylococcus aureus mastitis by immunization and intramammary insertion of a polyethylene device (Stérilait)].

The susceptibility of lactating cows to experimental challenge with two strains of Staphylococcus aureus was investigated 30 days after calving. These cows were previously immunized during the dry-period and udder quarters were fitted at drying-off with a polyethylene intramammary device (IMD). Incidence of infection recorded in device-fitted quarters and control quarters was not significantly different. There was no difference between IMD-fitted and control quarters in milk yield, contents in butterfat and protein. Lactose mean concentration was significantly decreased in milk collected from quarters fitted with polyethylene loop (P less than 0.05). The somatic cell counts in milk from quarters depended on: a) fraction collected, b) time of sampling, c) presence of intramammary loop, d) result of experimental challenge. Milk somatic-cell counts determined at mid-lactation for fractions collected before udder stimulation and total milk in IMD fitted quarters were greater than for control quarters (P less than 0.05). In general, these differences were greater in quarters which were experimentally infected than uninfected quarters. The count in total milk collected at mid-lactation for uninfected device-fitted quarters averaged 720 000 cells/ml.

Animals↗
PubMed1982

Lactoferrin and transferrin in bovine milk in relation to certain physiological and pathological factors.

Mean transferrin and lactoferrin concentrations in whey samples from 376 uninfected quarters of 42 Holstein X Friesian cows on the 30th, 150th and 270th days of lactation were respectively 0.030 and 0.080 mg/ml. The mean transferrin concentration in serum was 4.63 mg/ml. Lactation number and location of quarters did not influence milk lactoferrin and transferrin values. Lactoferrin concentration increased significantly (P less than 0.01) in uninfected quarters from 0.03 to 0.06 and to 0.15 mg/ml on the three successive sampling times. Transferrin whey concentration increased significantly (P less than 0.01) only in late lactation, from 0.025 (30th and 150th days of lactation) to 0.035 mg/ml (270th day of lactation). Lactoferrin concentration increased significantly (P less than 0.01) in quarters infected by major pathogens (41 samples) whereas minor pathogen infections (61 samples) caused no significant increase. The correlation coefficients between milk lactoferrin and transferrin concentrations and somatic cell-count were 0.42 and 0.65 respectively.

Age Factors↗
PubMed1982

Predicting the probability of quarter infection (by major pathogens) from somatic cell concentration.

The herd factor did not significantly affect distributions of somatic cell counts of 6,560 milk samples (collected in 3 herds) within an infection status. Minor-infections distribution for a herd was closer to that of healthy quarters than that of major infections. About 35% of the quarters infected by major pathogens had counts less than 400,000 cells/ml. Statistical analysis by conditional probability indicated that herd major-infection level should be taken into account to predict the probability of quarter infection by major pathogens. Discrimination with a good reliability between presence and absence of pathogens, as estimated by a single somatic cell count, is possible only in herds with high major-infection level.

Age Factors↗
PubMed1982

Dynamics of nonclinical bovine intramammary infections with major and minor pathogens.

Udder infections were recorded in 3 herds throughout a lactation period with bacteriologic examination being done at 3-week intervals. New infection rates and levels of infection at calving differed significantly (P less than 0.001) between herds, but persistence of infection did not. Of the 324 infections, 80.5% lasted up to drying off. Of quarters infected with major pathogens, 16.8% eliminated their infection (63% became reinfected); 20.8% of quarters infected with minor pathogens eliminated their infection (43% became reinfected). Significant differences in persistence of infections, quarter clearing rate (defined as the rate at which infected quarters become and remain noninfected) and ability to give way to and to take place of a preexistent infection, did not occur between Corynebacterium bovis and major pathogens. Though 66% of coagulase-negative staphylococci infections persisted up to drying off, they disappeared more frequently (P less than 0.01).

Animals↗
PubMed1981

Lysostaphin disk test for routine presumptive identification of staphylococci.

The sensitivity of the lysostaphin disk test was evaluated for routine differentiation of staphylococci from micrococci. Lyophilized paper disks impregnated with 10 micrograms of lysostaphin were placed on a Mueller-Hinton agar plate inoculated with 10 species of staphylococci and 7 species of micrococci. After 16 h of incubation at 37 degrees C, a circular zone of growth inhibition was noted for all staphylococci species tested. By contrast, all the micrococci species were resistant. The activity of the impregnated disks was not diminished by storing them at 4 degrees C for 3 months. With disks impregnated by 10, 6.6, 5, and 2.5 micrograms of lysostaphin, diameters of the growth inhibition zone for S. aureus Cowan 1 NCTC 8530 strain were proportional to the logarithm of the quantity of lysostaphin present in each disk.

Bacteriological Techniques↗
PubMed1981

California Mastitis test guide of selective dry cow therapy.

California Mastitis Test scores and bacteriological analysis of quarter foremilk samples from 133 cows of three herds were used to determine which quarters or cows to treat in a selective dry cow therapy program. Effect of score, week of the test, and type and number of intramammary infections were examined. Score was independent of the type of intramammary pathogen infection. When all positive reactions were considered, approximately 80% of the infections by major pathogens were diagnosed on a single milk sample taken at either 8 or 4 wk before drying off. At 8 and 4 wk, 13 and 23% of samples from uninfected quarters or quarters infected with minor pathogens had positive reactions. Selective treatment of all cows that had one or more positive quarters led to treatment of twice as many quarters than if only positive quarters were treated. The most discriminating, simplest, and economic method of selective treatment was one test on quarter foremilk samples collected 8 wk before the expected dry-off and dry treatment of all positive mammary quarters.

Animals↗
PubMed1980

Protective effect in the lactating bovine mammary gland induced by coagulase-negative staphylococci against experimental Staphylococcus aureus infections.

The susceptibility of quarters preinfected either experimentally with Staphylococcus epidermidis or Staphylococcus xylosus or naturally by other coagulase-negative staphylococci was measured after challenge with two different strains of Staphylococcus aureus. The proportion of infected control quarters (95%) was raised significantly higher than that of those preinfected by the coagulase-negative staphylococci (24.5%). Differences were observed in the frequency of superinfection of the quarters according to the strain of the preinfective coagulase-negative staphylococcus, duration of preinfection and somatic cell count at the time of challenge. The protective mechanism against Staph. aureus induced by preinfection with coagulase-negative staphylococci is discussed.

Animals↗
PubMed1979

Evaluation of three rapid tests for identification of Staphylococcus aureus isolated in bovine milk.

In order to develop a routine and rapid method for the identification of Staphylococcus aureus isolated from bovine milk, three tests were evaluated with 200 strains isolated from different regions. Tests were performed with colonies isolated from the initial agar plate medium. Clumping factor reations were positive with 93.5% of the strains, beta hemolysin with 76% and protein A with 56% of them. It was found the three tests were never all negative for any particular strain. A scheme for rapid identification is proposed.

Agglutination Tests↗
PubMed1978

Induced staphylococcal infections in the bovine mammary gland.

In a study to develop and define a practical model of bovine mastitis caused by Staphylococcus aureus, induced infections were attempted in 203 bovine mammary glands of 41 cows, using 12 strains of S aureus. Approximately 100 colony-forming units of S aureus in saline solution were injected after milking, and milk samples were collected daily from test glands for 14 days to monitor the progress of infections and inflammatory responses. Relationships were examined for cow-related factors and for various characteristics of the strains of S aureus used to the development of a persistent intramammary infection. A dairy cow that was useful in this model was defined as follows: (1) the 2nd to 7th month in the 1st to 5th lactation; (2) producing milk from all mammary glands that contained less than 6 x 10(5) somatic cells/ml; and (3) having mammary glands that were free of any primary mastitis pathogen, as well as micrococci and Corynebacterium bovis. From the present study, it was not possible to define clearly a strain of S aureus which would be useful in the model, but 5 strains of S aureus were identified as being capable of producing persistent subacute infections with a high degree of repeatability.

Animals↗