Biomedical subjects

J W Pankey

Publications and source records attributed to J W Pankey.

At least 37 records · Page 2Linked to original sources

PubMed1992

Increased susceptibility to intramammary infection following removal of teat canal keratin.

Influence of teat canal keratin on susceptibility to intramammary infection was investigated in lactating Jersey cows. In each of two replicate trials, keratin was removed from the left teats of 20 cows immediately before milking. Immediately after milking, all teats were exposed to bacterial challenge by immersion in a suspension of Streptococcus agalactiae (5 x 10(7) cfu/ml). Bacterial challenge was repeated after the next four milkings. Foremilk samples were obtained for 8 d after keratin removal to determine infection status. A mammary quarter was classified as infected based solely upon the bacteriological criteria outlined by the National Mastitis Council. The rate of infection in quarters from which keratin was removed was greater than that in control quarters. Infection rates were 26.3% for keratin-removed quarters and 8.3% for control quarters in trial 1 and 13.5 and 0%, respectively, in trial 2. When more stringent criteria (recovery of greater than 100 cfu of S. agalactiae/ml in three or more successive milk samples and a SCC of greater than 10(6)) were used to identify a subset of infections that were clearly intramammary, infection rates were 9.3% for keratin-removed quarters and 1.4% for control quarters. Thus, partial removal of keratin from the teat canal compromised the ability of the teat to prevent passage of bacterial pathogens from the external environment into the mammary gland.

Animals↗

PubMed1991

Lipid composition of teat canal keratin collected before and after milking from Holstein and Jersey cows.

In three experiments, keratin was collected from individual teats of 40 Holstein and 20 Jersey cows immediately before and after milking. In Experiments 1 and 2, keratin collected from teats of 20 Holstein cows before milking was compared with keratin collected after milking. In Experiment 3, keratin was collected from two teats of 20 Jersey and 20 Holstein cows before milking and compared to the other two teats of the same cows after milking. All three experiments yielded similar results. In Holsteins, keratin weight before milking was 1.6 times greater than keratin weight after milking (3.1 vs. 1.9 mg). In Jerseys, only small amounts of keratin were removed during milking (3.5 mg before vs. 3.1 mg after) In Holsteins and Jerseys, neutral lipid concentration was 1.6 times greater after milking than before, suggesting that when keratin was removed during milking, only moderate amounts of lipid were removed. In Holsteins, total lipid collected per teat was similar before or after milking (59.2 vs. 48.5 micrograms). Results demonstrate that keratin collected after milking had a different lipid composition than keratin collected before milking.

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PubMed1991

Mastitis prevalence in primigravid heifers at parturition.

Prevalence of intramammary infection was determined for 382 primigravid heifers within 3 d postpartum on 11 Vermont dairy farms. Data collected during a 5-yr period are summarized. Duplicate quarter milk samples were cultured on tryptose-blood agar plates containing .1% esculin. Intramammary infections were diagnosed in 45.5% of the heifers and 18.7% of quarters. Staphylococcus species were the most prevalent bacteria isolated: they appeared in 25.4% of the heifers and 12.1% of quarters. Only 2.6% of the heifers were diagnosed with Staphylococcus aureus; 22.8% had udder infection caused by other staphylococcal species. Environmental mastitis pathogens, coliforms, and streptococci other than Streptococcus agalactiae were isolated from 14.9% of the heifers and 4.8% of quarters. The prevalence of mastitis among these primigravid heifers at parturition indicates a need to improve methods of diagnosis and control programs.

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PubMed1990

Evaluation of a chlorous acid-chlorine dioxide teat dip under experimental and natural exposure conditions.

A postmilking teat dip containing chlorous acid-chlorine dioxide was evaluated by experimental challenge and in two herds under natural exposure. The test product had an efficacy of 78.9% against Staphylococcus aureus and 52.5% against Streptococcus agalactiae in the experimental challenge trial. The product was compared with a 1% iodine product in a 15-mo natural exposure study. Post-dipping with chlorous acid-chlorine dioxide reduced incidence of udder infection by major mastitis pathogens 36.1% when data were combined from the two herds. The 1% iodine and the chlorous acid-chlorine dioxide products were not equivalent for major mastitis pathogens; the test product was more effective. Incidence of udder infection by environmental mastitis pathogens was reduced 36.8% in both herds combined. Efficacy of the two teat dips was equivalent for environmental pathogens.

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PubMed1989

Premilking udder hygiene.

Incidence of intramammary infection is highly correlated to the number of mastitis pathogens on the teat end at milking. The objective of premilking teat sanitation is to reduce the microbial population in order to minimize the probability of mastitis. Milking time hygiene is extremely important due to the potential interaction between milking machine functions and microflora of teat skin. Current recommended procedures for premilking udder preparation range from water hose wash, manual drying, wet paper towel wash plus paper towel dry, to predipping alone plus paper towel dry. Regardless of udder cleaning procedure, manual drying of teats is a significant factor in reduction of total bacteria counts. Predipping with iodine-based sanitizers, .1 to .25% iodine concentration, reduced intramammary infection with environmental pathogens 51% compared with good udder preparation in a field trial on four commercial dairy farms. Infections by coagulase-negative staphylococci were not reduced by predipping. Effective premilking udder hygiene is essential for the production of high quality milk. Bacteria, preincubation and pasteurized milk counts are reduced. Sediment is minimized. Incidence of mastitis is reduced. Proper udder hygiene procedures should be practiced at every milking.

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PubMed1987

Field trial evaluation of premilking teat disinfection.

Efficacy of premiliking teat disinfection (predipping) with good udder preparation was compared with good udder preparation alone on four well-managed, commercial dairy farms. Three teat dip formulations containing iodophor were used for predipping. Predipping reduced the rate of intramammary infection with major mastitis pathogens approximately 54%. Infection rate with esculin-positive streptococci and coliforms was reduced more than 51%. Udder infections with coagulase-negative staphylococci were not controlled by predipping.

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PubMed1987

Effects of teat dipping on intramammary infections by staphylococci other than Staphylococcus aureus.

Effects of intramammary infections in herds 1) either not teat dipping or postmilking teat dipping with either 2) linear dodecyl benzene sulfonic acid, 3) chlorhexidine, or 4) iodophor containing products were determined. Duplicate quarter foremilk samples were collected once from all lactating cows in 16 herds, four for each practice. Mean percentage of quarters infected with Staphylococcus species other than Staph. aureus was 11.0 in herds not teat dipping and 7.2 in herds teat dipping. Prevalence of Staphylococcus species intramammary infections in herds teat dipping with linear dodecyl benzene sulfonic acid was comparable to herds not teat dipping and greater than in herds using chlorhexidine and iodophor. The predominant Staphylococcus species in herds not teat dipping was Staph. epidermidis (37.1%). Staphylococcus hyicus constituted 48.5% of total Staphylococcus species intramammary infections in herds teat dipping and 12.4% in herds not teat dipping. Differences were not observed among SCC for quarters infected with different Staphylococcus species. Application of germicidal teat dips appeared to have selectively altered both prevalence and distribution of Staphylococcus species intramammary infections.

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PubMed1987

Growth inhibition of mastitis pathogens by long-chain fatty acids.

Staphylococcus aureus, Staphylococcus hyicus, Streptococcus agalactiae, and Corynebacterium bovis were tested for sensitivity to long-chain fatty acids predominant in teat canal keratin. Antibacterial activity of free fatty acids on each bacterial species was measured after 12 and 24 h in chemically defined media. Polyene C18:2 and C18:3 acids were bactericidal to each species at less than or equal to 10(5) ng/ml-1. The most bacteriostatic saturated fatty acids were C12 and C14. Streptococcus agalactiae growth was inhibited more by fatty acids after 24 h than after 12 h. No incubation time effect on growth responses of other species was determined. Polyoxyethylenesorbitan monooleate had a neutralizing effect on the bactericidal activity of polyene acids on C. bovis. Corynebacterium bovis were unable to grow in synthetic media containing individual free fatty acids as the sole source of preformed fatty acids. A relationship between bacterial species commonly isolated from bovine teat canals with resistance to fatty acids predominant in keratin was not evident.

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PubMed1987

Growth responses of Staphylococcus aureus and Streptococcus agalactiae to Corynebacterium bovis metabolites.

Staphylococcus aureus and Streptococcus agalactiae growth responses to metabolites of Corynebacterium bovis cultured in media containing polyoxyethylenesorbitan monolaurate, monooleate, or trioleate and milk were determined. Filter sterilized metabolites of 48-h C. bovis cultures in synthetic media were added to cultures of Staph. aureus and Strep. agalactiae. Staphylococcus aureus and Strep. agalactiae were inoculated into 12-h C. bovis milk cultures. Growth responses of Staph. aureus and Strep. agalactiae were not affected by C. bovis metabolites of synthetic media. Staphylococcus aureus growth was inhibited during logarithmic and stationary phases in milk containing mixed cultures of C. bovis compared with growth in pure Staph. aureus cultures. Streptococcus agalactiae growth curves were similar in pure and C. bovis mixed cultures. Fatty acid compositions were not different in sterile milk and milk containing bacterial cultures. Growth responses of Staph. aureus and Strep. agalactiae were not related to concentration of C. bovis metabolites or fatty acid content of media in which C. bovis were cultured.

Corynebacterium↗

PubMed1986

Prevalence and effects of intramammary infection in beef cows.

Prevalence and effects of intramammary infection in 322 beef cows was determined during three calving intervals. Intramammary infection was confirmed in 37% of cows and 18.1% of quarters. Coagulase-positive staphylococci accounted for 17.9% of infections with Staphylococcus aureus isolated from 7.1% of cows. Coagulase-negative staphylococci and micrococci accounted for the remainder of infectious organisms. Butterfat and total protein levels were reduced 27.3 (P less than .05) and 25.5% (P less than .01), respectively, in milk from quarters infected with S. aureus. Somatic cell counts were elevated (P less than .001) with 3,827 X 10(3) cells/ml for S. aureus-infected quarters as compared with 555 X 10(3) cells/ml for uninfected quarters. Somatic cell counts were negatively correlated with 210-d calf weaning weights. Staphylococcus aureus-infected cows weaned calves weighing 19.1 kg less (P less than .01) than uninfected cows. At a present market value of $1.65/kg, economic losses were placed at $31.43/calf from cows infected with S. aureus in one or more quarters.

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PubMed1986

Evaluation of .5% and 1% iodophor teat dips on commercial dairies.

Two postmilking teat dips containing .5 and 1% iodine were evaluated for approximately 8 mo under conditions of natural exposure to mastitis pathogens on four commercial dairy farms. In the two herds using .5% iodophor, incidence of intramammary infection with Staphylococcus aureus and Streptococcus agalactiae was reduced 68.3 and 46.2%, respectively. When numbers of new infections with both pathogens were combined, efficacy for the .5% iodophor was 62.3%. In the two herds using 1% iodophor, incidence of intramammary infection with Staph. aureus and Strep. agalactiae was reduced 52.4 and 70.7%, respectively. When numbers of new infections with both pathogens were combined, efficacy for the 1% iodophor was 64.3%. Efficacy of teat dips was variable against coagulase-negative staphylococci and Corynebacterium bovis.

Animals↗

PubMed1986

Fatty acid composition of bovine teat canal keratin.

Keratin from 507 excised teats was pooled, separated into three samples, and analyzed for fatty acid composition of extracellular and intracellular lipids. Mean weight of keratin collected per teat canal was 8.97 mg. Extracellular lipids were recovered in petroleum ether. Intracellular lipids were extracted in chloroform: methanol (2:1, vol/vol) solution. Average keratin wet weight of extracellular and intracellular lipid fractions were 37.1 and 21.9 mg/g, respectively. Polar and nonpolar lipids were present in both fractions. Predominant fatty acids in extracellular and intracellular lipids were C16, C18:1, and C18. Extracellular lipids contained greater concentrations of C4 to C18:1 fatty acids than did intracellular lipids. Percent of total fatty acid weight comprised by each of C4, C10, C12 and C14 was also significantly greater in extracellular than intracellular fractions. Intracellular lipids contained a greater concentration and percent total fatty acid content comprised by C18:2 than extracellular lipids. Data suggest lipids accessible at the keratin interface are in part of milk fat origin.

Animals↗

PubMed1986

Comparison of four test procedures to identify Staphylococcus aureus isolated from bovine intramammary infections.

A comparison was made between conventional tube coagulase, macrocupsular coagulase, latex agglutination, and miniaturized biochemical test systems for identification of Staphylococcus aureus of bovine origin. A total of 303 gram-positive, catalase-positive cocci of bovine origin were tested. Agreement between each pair of 4-hour tube coagulase, macrocupsular coagulase, latex agglutination, and miniaturized biochemical test results within isolates was greater than 95.0. Seventeen (5.6%) isolates were test negative for 4-hour tube coagulase, but test positive for 24-hour tube coagulase. Thirteen (76.5%) of these isolates were identified as S hyicus, 3 were S aureus, and 1 was not identified.

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PubMed1985

Efficacy evaluation of two new teat dip formulations under experimental challenge.

Two new teat dip formulations were evaluated against Streptococcus agalactiae and Staphylococcus aureus in half-udder, experimental challenge studies. The first product contained a combination of 1.9% linear dodecyl benzene sulfonic acid - .55% iodophor. Incidence of infection was reduced 52.7 and 70.7% for Streptococcus agalactiae and Staphylococcus aureus in dipped quarters compared to undipped controls. The second formulation was a barrier-type product consisting of milk protein solubilized with lauryl sulfate, a surface active detergent and 4.8% glycerin. Rates of infection were reduced 60.3 and 67.9% for Streptococcus agalactiae and Staphylococcus aureus.

Animals↗

PubMed1985

Evaluation of protein A and a commercial bacterin as vaccines against Staphylococcus aureus mastitis by experimental challenge.

Protein A and a commercial staphylococcal bacterin were evaluated by experimental challenge with Staphylococcus aureus (ATCC 29740). Thirty cows in first lactation were in three treatment groups, protein A, bacterin, and nonvaccinated controls. Studies were through three lactations and included bacteriological and cytological analyses of quarter milk samples. Rate of intramammary infection with Staphylococcus aureus was similar for vaccinated and unvaccinated cows. Rates of spontaneous cure within each lactation were significantly higher for vaccinated cows. For all three lactations, spontaneous cure rates were 83, 73, and 47% for protein A, bacterin, and control cows. Somatic cell counts were significantly lower for vaccinated cows for quarters infected with Staphylococcus aureus, but no differences were demonstrated for milk production by lactation. Incidence of clinical mastitis was higher in unvaccinated cows, but too few developed for a valid comparison.

Animals↗

PubMed1985

Field studies on linear dodecyl benzene sulfonic acid teat dip.

A teat dip containing 1.94% linear dodecyl benzene sulfonic acid and 12% glycerine, an anionic detergent formulation, was evaluated in two field trials on a commercial dairy. In Trial 1, the teat dip was compared to an undipped control in a split-herd design. Incidence of infection with Streptococcus agalactiae was reduced 57.8%; infections with presumptively identified Staphylococcus aureus were not reduced. Milking machine function and milking procedures may have affected teat dip effectiveness and incidence of udder infection. Streptococcus agalactiae was eradicated prior to Trial 2 in which the detergent teat dip was compared to a 1% iodophor product of proven efficacy. Incidence of Staphylococcus aureus infection was 40.5% lower in the detergent than in the iodophor group. Taxonomic studies on Staphylococcus species indicated that presumptive microbial identification resulted in erroneous conclusions concerning efficacy of the teat dip products. Importance of speciation of staphylococcal isolates is discussed.

Animals↗

PubMed1985

Effects of Corynebacterium bovis infection on susceptibility to major mastitis pathogens.

Experimental challenge procedures were used to study infectivity and virulence of Corynebacterium bovis. Challenge procedures using Staphylococcus aureus (Newbould 305) and Streptococcus agalactiae (McDonald 44) were used to study effects of Corynebacterium bovis infections on superinfection with major pathogens. Rate of infection under experimental challenge conditions was significantly greater with Corynebacterium bovis than previously observed for Staphylococcus aureus or Streptococcus agalactiae. Principal location of Corynebacterium bovis colonization appeared to the teat canal region, although the organism was isolated from 75% of the teat cisterns by puncture technique. Quarters with Corynebacterium bovis infections were more resistant to infection by Staphylococcus aureus than bacteriologically negative quarters. Quarters infected with Corynebacterium bacterium bovis were approximately 8.5-fold more susceptible to Streptococcus agalactiae infection than negative quarters. Somatic cell counts were doubled in negative quarters that developed Corynebacterium bovis infections; the geometric mean was 2.4 X 10(5).

Animals↗

PubMed1985

Electron microscopic study of leucocytic infiltration of the mammary teat duct during infection with Staphylococcus aureus.

Leucocytic response to Staphylococcus aureus infection was observed in the bovine mammary teat duct using transmission electron microscopy. Leucocytes migrating across the stratified squamous epithelium were observed in close association with areas colonised by cocci. Leucocytes gained access across the epithelium to the teat duct lumen by: passage as luminal cells desquamated; migration through degenerate cell cytoplasm; and penetration of cell junctions. The results provide evidence of marked leucocytic infiltration into ductal tissue which may participate in the cellular response to mastitis.

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