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PubMed1981

Comparison of single and multiple-trait selected sires. Response in mastitis traits.

Estimated somatic cell counts and incidence mastitis were measured on 163 daughters of two groups of bulls selected by two alternative criteria. Yield bulls were selected solely on progeny test for milk in first lactation; Merit bulls were selected by independent culling levels on fat-corrected milk yield, percent daughters culled in first lactation, and udder type conformation of daughters. Daughters of Yield sires exceeded daughters of Merit sires by 685 kg milk in first lactation. Groups did not differ significantly in measures of clinical mastitis or in measures of estimated cell counts of milk. Also, groups did not differ in kilograms milk discarded because of antibiotic treatment for mastitis, in spite of the large difference in total milk yield. Mean milk discarded per lactation completed was 171 kg, representing 64,243, and 207 g for parities one, two, and three.

Animals↗
PubMed1982

Electrical conductivity of milk for detection of mastitis.

The potential value of electrical conductivity of milk as a screening test for subclinical mastitis was evaluated. Conductivity of foremilk and of postmilking strippings from 368 quarters of 92 cows was measured. Infection status of quarters was determined by bacteriological analysis of strict foremilk samples. Infections were classified as by primary or secondary pathogens, depending on the importance of the isolated organism as a mastitis pathogen. Somatic cells were counted on foremilk samples. Milk conductivity increased with infection. Conductivity of postmilking strippings was higher than that of foremilk in samples from quarters infected by primary pathogens. By thresholds which correctly classified at least 90% of normal quarters, accuracy of identifying primary pathogen infections by absolute conductivity was 62.8 and 96.2% with foremilk and postmilking strippings. Differential conductivity and combination of absolute and differential methods also were evaluated with the latter being the most effective. Number of quarters with elevated conductivity of postmilking strippings tended to be higher when somatic cell count was greater than 500,000/ml in both normal and infected groups. Conductivity of milk seems to hold promise as an indicator of subclinical mastitis.

Animals↗
PubMed1983

Germicidal teat dip in a herd with low prevalence of Streptococcus agalactiae and Staphylococcus aureus mastitis.

Effectiveness of an iodophor teat dip in reducing new intramammary infection and clinical mastitis was tested in a herd free of Streptococcus agalactiae and with a low prevalence of Staphylococcus aureus infections. In this 6-mo study with an average of 152 lactating cows on trial on sampling dates, right rear and left front teats were dipped after each milking while right front and left rear teats were undipped controls. Teat dipping significantly reduced new infections by Staphylococcus aureus, streptococci (other than Streptococcus agalactiae), coagulase-negative staphylococci, and Corynebacterium bovis and reduced clinical cases caused by infections established during the trial. However, the dip did not reduce new infections or clinical mastitis caused by coliform bacteria. Therefore, use of a germicidal dip is recommended for herds with a low prevalence of Streptococcus agalactiae and Staphylococcus aureus, but the practice should not be expected to control coliform mastitis.

Administration, Topical↗
PubMed1983

Iodine in field milk samples and effects on mastitis organisms.

Bulk tank milk samples collected from 175 dairy herds throughout Wisconsin averaged 466 micrograms of iodine per liter with 11% of the samples containing greater than 1000 micrograms per liter. From questionnaires on feeding and management, use of iodine supplements in feed was associated with increased iodine in milk. One gram of ethylenediamine dihydriodide was fed daily for 2 wk to dairy cows with a history of mastitis. Milk iodine increased from 210 to 6225 micrograms per liter. There was no significant effect on somatic cells, mastitis organisms, or incidence of clinical mastitis.

Animals↗
PubMed1984

Effect of vitamin E and selenium supplementation on incidence of clinical mastitis and duration of clinical symptoms.

Incidence of clinical mastitis and duration of clinical symptoms for complete lactations were evaluated for 80 cows randomly assigned to one of four groups: vitamin E supplemented- and selenium injected, selenium injected, vitamin E supplemented, and controls. Vitamin E supplementation and selenium injection were during the dry period. Log-linear analysis of incidence data revealed a significant 37% reduction of clinical mastitis by vitamin E. Incidence was not affected by selenium alone, nor was there any evidence for interaction of vitamin E with selenium on incidence. However, duration of clinical symptoms (calendar months clinical/quarter lactating) was reduced by 46% for the selenium group, 44% for the vitamin E group, and 62% for the vitamin E-selenium group as compared to controls. We conclude that dairy cow diets deficient of vitamin E may elevate incidence of clinical mastitis. Selenium deficiency may result in greater duration of clinical symptoms, and selenium may interact with vitamin E. Coliform bacteria and species of streptococcus other than Streptococcus agalactiae were isolated from 70% of the clinical cases.

Animals↗
PubMed1984

Peripartum changes of plasma and milk vitamin A and beta-carotene among dairy cows with or without mastitis.

Over 12 mo we studied the relationship between peripartum concentrations of vitamin A and beta-carotene in blood plasma and milk of 93 Holsteins with or without subsequent mastitis. Blood was sampled daily from 7 days prepartum through 7 days postpartum and on alternate weeks through wk 10 of lactation. Milk samples were collected daily for 7 days postpartum and then biweekly for 10 wk. Somatic cell counts were on biweekly milk samples. Vitamin A and beta-carotene of blood plasma decreased rapidly prepartum to reach minimum concentrations at calving (vitamin A) or on day 4 to 6 postpartum (beta-carotene). Thereafter, both vitamin A and beta-carotene increased rapidly through 10 wk postpartum. Concentrations of vitamin A and beta-carotene in colostrum were higher than concentrations in milk. Cows with mastitis (somatic cells greater than 500,000 cells/ml milk) had lower vitamin A in blood plasma during days 0 to 7 and wk 2 and 4 postpartum than cows without mastitis. When data were analyzed with loge of somatic cell count as an independent regression variable, results were similar. In contrast to vitamin A, peripartum beta-carotene in blood plasma was higher among mastitic cows and was related to higher loge of somatic cell count. No significant difference was observed between mastitic and non-mastitic cows for vitamin A and beta-carotene in milk. Lower concentrations of plasma vitamin A and higher concentrations of beta-carotene during the immediate postpartum period were associated with higher milk somatic cell counts among dairy cows during lactation.

Animals↗
PubMed1984

Effect of dietary vitamin A on resistance to experimental Staphylococcus mastitis in mice.

Weanling mice (118) were fed a purified diet free of vitamin A for 3 wk and subsequently assigned to diets containing 10, 100 (4000 IU vitamin A/kg diet), or 300% of National Research Council recommended vitamin A. After 3 wk on the treatment diet all mice were bred and allowed to complete gestation. At 24 h postpartum, the left fourth abdominal mammary gland of each mouse was inoculated with Staphylococcus aureus (10(8) cells in .1 ml of saline/gland), and mammary gland infection was observed daily for 6 consecutive days. Liver vitamin A content was lowest in mice for 10% and highest for 300%. However, mice fed 10% showed normal growth and reproduction by small treatment differences in body weight changes, litter size at birth, and average pup weight. Mice fed 10 and 100% vitamin A showed more severe mammary gland inflammation after intramammary inoculation as opposed to mice fed 300%. Severity of mastitis in mice fed 100% vitamin A was similar to 10%. The number of mice classified as mastitic was also similar between 10 and 100% on days 1 and 2 postinoculation; however, on day 3 postinoculation mice fed 100% had a lower incidence of mastitis as opposed to 10%. Severity of mammary inflammation on days 4 through 6 were similar to those on day 3. Results showed a protective effect of dietary vitamin A supplementation against experimental Staphylococcus aureus mastitis in mice.

Analysis of Variance↗
PubMed1985

Detection of bovine mastitis by bromothymol blue pH indicator test.

A simple bromothymol blue indicator test was evaluated for farm diagnosis of mastitis. The test required highly absorbent blotting paper impregnated with four spots of bromothymol blue. Indicator color scores (1 to 4) for quarter foremilks increased with somatic cell count and pH, although variability within each color score was large. Sensitivity of the bromothymol blue test ranged from 51 to 56% and specificity from 89 to 90% for most reference criteria used to classify normal and abnormal milk. Predictability of a positive test ranged from 49 to 52% (false positives 51 to 48%) and predictability of a negative test from 90 to 97% (false negatives 10 to 3%) for the same criteria. Overall the bromothymol blue test incorrectly diagnosed 11 to 20% of 3772 quarters. By classifying color score 2 as negative, predictability of a positive result was 70 to 75% and sensitivity was 26 to 30%. The test can be used by dairy producers to screen herds with a relatively high incidence of mastitis or used in combination with cow cell counts to locate abnormal quarters. The bromothymol blue test was less sensitive than the California Mastitis Test but offered several practical advantages for use on farm.

Animals↗
PubMed1985

Lipoprotein lipase activity of milk from cows with prolonged subclinical mastitis.

The influence of prolonged subclinical mastitis on bovine milk lipoprotein lipase activity was investigated. Nine cows with at least one quarter with prolonged subclinical mastitis and at least one nonmastitic quarter were selected in various stages of lactation. Milk from subclinical quarters had a mean somatic cell count of 5.7 X 10(6) cells/ml while milk from nonmastitic quarters had an average somatic cell count of 9.4 X 10(4) cells/ml. Quarters with a subclinical infection contained the same pathogenic organisms for a minimum of 6 wk. The average milk lipoprotein lipase activity of 108.7 units/ml milk from subclinical quarters was 27.1% higher than the average enzyme activity of 79.2 units/ml milk from nonmastitic quarters. Conditions present in the mammary gland during prolonged subclinical mastitis could lead to increased milk lipoprotein lipase activity in raw milk.

Animals↗
PubMed1985

Path model of reproductive disorders and performance, milk fever, mastitis, milk yield, and culling in Holstein cows.

Path analysis was used to model the direct and indirect relationships among age, previous lactation yield or estimated transmitting ability for milk, body weight, days dry, reproductive disorders, milk fever, mastitis, reproductive performance, current milk yield, and culling. Prospective data were from 784 primiparous and 2,066 multiparous Holstein lactations from 33 herds. Heifers that were older, of lighter weight, or who had lower estimated transmitting ability for milk had more problems, less milk, and poorer survival. Dystocia in heifers had several detrimental consequences including 2.9 to 4 times more retained placenta, metritis, and culling and +7.4 d more to first service. Cystic ovaries were associated directly with 376 kg greater milk yield and with a 16.5-d delay in first service. Failure to conceive at first service and mastitis increased risk of culling 5.2 to 10 times. In multiparous cows, milk fever increased risk of reproductive disorders by 1.6 to 4.2 times and indirectly contributed to poor breeding performance and increased culling. Risk of culling was increased 2.1 to 3.7 times directly by mastitis and dystocia and by poor breeding performance.

Age Factors↗
PubMed1988

Characterization of clinical mastitis records from one herd in a subtropical environment.

Patterns of occurrence and reoccurrence of clinical mastitis, duration of episodes, and number of quarters treated in a large north Florida dairy over 6.5 yr are described. Monthly incidence of milk disposal due to clinical mastitis varied within and between years and ranged from 1.3 to 4.7% of cow-days in milk. In first parity animals, 37.6% of lactations were treated for clinical mastitis, averaging 1.4 episodes per treated lactation. Almost half of these episodes occurred by d 35 of lactation. For second, third, and fourth or greater parities, 35.5, 48.1, and 56.6% of lactations were treated. These lactations averaged 2.1, 2.3, and 2.8 episodes. In parities 2, 3, and greater than or equal to 4, episodes initiated by d 35 of lactation were 28.2, 23.9, and 20.6% of parity episodes. Seventy-two percent of episodes were treated for less than or equal to 7 d. Sixty-seven percent of episodes were treated in one quarter and treatment in two, three, or four quarters accounted for 21.6, 5.5, and 5.9% of all episodes. When two quarters were treated simultaneously, udder halves (front, rear, right, left) were treated more frequently than were diagonals.

Animals↗
PubMed1990

Effect of severity of systemic signs during the acute phase of experimentally induced Escherichia coli mastitis on milk production losses.

The objectives were to describe the systemic signs during the acute phase of experimental Escherichia coli mastitis and to relate these with losses in milk production during the reconvalescent period. Eleven cows, 20 to 30 d postpartum, were inoculated with 10(4) cfu of E. coli O157 in rear quarters. Heart rate, rectal temperature, frequency and amplitude of rumen contractions, plasma Zn and Fe concentrations, and counts of E. coli were used to monitor severity of disease during the acute phase. Areas under curves of clinical parameters, plasma Zn and Fe concentrations, and counts of E. coli were calculated during 36, 120, and 125 h postinoculation, respectively. Areas under curves of milk production were calculated during 21 d postinoculation. Losses in total daily milk production were related positively with areas under curves of heart rate, rumen amplitude, counts of E. coli in secreta from inoculated quarters, and plasma Zn and Fe concentrations. These parameters may prove suitable to establish an accurate prognosis for returning to milk production cows suffering from acute or peracute E. coli mastitis and to evaluate efficacy of drugs in experimental mastitis.

Acute Disease↗
PubMed1990

Mastitis control practices: differences between herds with high and low milk somatic cell counts.

Effects of differences in herd mastitis control management in maintaining low herd average SCC, was studied. Washington State DHI herds with Holstein cattle and enrolled in the SCC program (n = 309) were ranked by percentage of cows in their herd with SCC less less than or equal to 283,000 cells/ml. "Low herds" (n = 28) were among the 56 herds with the highest percentage of cows with SCC less than or equal to 283,000 cells/ml and "high herds" (n = 31) were among the 75 with the lowest percentage of cows with SCC less than or equal to 283,000 cells/ml. Herds were visited annually for 2 yr by a technician who collected samples and recorded data. Geometric mean bulk tank SCC during the year between herd visits was 175,000 and 460,000 cells/ml for low and high herds. Milking time hygiene practices, teat dipping, and dry cow therapy were practiced with equal frequency on low and high herds. Differences in function and maintenance of milking equipment did not discriminate between herd groups. Differences in mastitis control management of low versus high SCC herds were that managers of excellent control herds more frequently had highest producers milked first and clinical cows milked last; had automatic milking unit detachers; kept moisture content of cow bedding lower; and had workers disinfect teat ends prior to intramammary antibiotic treatment. Managers of low herds were more likely to use computers and attend dairy informational meetings. Results suggest subtle differences in mastitis control strategies differentiate the low and high SCC herd groups.

Animals↗
PubMed1991

Deacylation of endotoxin during natural cases of bovine mastitis.

Acyloxyacyl hydrolase, a lysosomal enzyme that deacylates and thus detoxifies lipopolysaccharide (endotoxin) has been identified in bovine peripheral blood and milk neutrophils. Enzymatic activity increases on a per neutrophil basis during cases of experimental Escherichia coli mastitis. The objective of this study was to quantify acyloxyacyl hydrolase activity from milk neutrophils collected from mammary glands naturally infected with a variety of bacteria. Acyloxyacyl hydrolase activity was detectable in milk neutrophils isolated from cases of both Gram-negative and Gram-positive bacterial infections, with highest activities found in milk neutrophils from glands infected with organisms known to cause the most severe forms of mastitis. In addition, acyloxyacyl hydrolase activity was inhibited to varying degrees in mastitic milk by a nonprotein inhibitory substance. Nonenzymatic deacylation of endotoxin also occurred in mastitic milk, but to a lesser degree than enzymatic deacylation. Nonenzymatic deacylation of endotoxin was not found to occur in clinically normal milk. Severity of coliform mastitis in individual cows may be dependent in part on the interaction of endotoxin with milk neutrophil acyloxyacyl hydrolase activity, inhibition of acyloxyacyl hydrolase activity by an inhibitory substance, and the inherent ability of milk to deacylate endotoxin nonenzymatically.

Animals↗
PubMed1991

Antigenic homology among gram-negative organisms isolated from cattle with clinical mastitis.

This study examined the degree of serologic homology among mastitis pathogens. Antibodies were raised against the Rc mutant, Escherichia coli O111:B4 (strain J5) and affinity purified against lipopolysaccharide derived from the Ra mutant, Salmonella typhimurium TV119. These antibodies reacted with a battery of unrelated Gram-negative bacteria in whole cell ELISA. Bacteria with strong cross-reactions included a heterologous, smooth E. coli, Salmonella dublin, S. typhimurium, Salmonella newport, and Pseudomonas aeruginosa. Recognition of Klebsiella pneumoniae and Bordetella bronchisepticum was observed, but reactions were weaker than with the other isolates. The reduced recognition of these isolates probably reflects a masking effect of the bacterial capsule and variations in lipopolysaccharide structure. The polyclonal antibody did not recognize a Gram-positive isolate, Staphylococcus aureus. These immunoglobulins were then tested using whole cell ELISA against a panel of bacteria recovered from the mammary glands of cattle with clinical mastitis. Marked reactivity was noted against a variety of Gram-negative pathogens. Gram-positive isolates had lower recognition by Gram-negative core antigen specific immunoglobulin. The results suggest immunization with rough mutant bacteria may have broad application in the prevention of coliform mastitis.

Animals↗
PubMed1991

Staphylococcus aureus mastitis: pathogenesis and treatment with bovine interleukin-1 beta and interleukin-2.

Polymorphonuclear leukocytes play a central role in the pathogenesis of bovine mastitis. Intramammary challenge with Staphylococcus aureus was shown to induce both quantitative and qualitative changes in mammary gland polymorphonuclear leukocytes. Intramammary infusion of recombinant bovine interleukin-1 beta and interleukin-2 elicited a similar cellular response. Staphylococcus aureus, interleukin-1 beta, and interleukin-2 all increased the number of somatic cells after intramammary infusion and activated the inducible superoxide production in milk polymorphonuclear leukocytes. Interleukin-2 also activated phagocytosis of these cells, and their activation was maintained for 3 to 5 d after intramammary administration. Interleukin-1 beta and interleukin-2 were moderately effective in the therapy of experimental S. aureus mastitis. Approximately 54% of the glands treated with interleukin-1 beta responded to therapy by transiently clearing the milk of S. aureus, 30% of which relapsed, and a total of 38% of the treated glands remained cured. In contrast, 83% of glands treated with interleukin-1 beta responded to therapy, but 50% of these quarters relapsed. A total of 42% of the quarters treated with interleukin-1 beta remained cured. Homologous recombinant cytokines are effective immunomodulators that augment natural defensive mechanisms similar to the normal response to pathogens and may prove to be suitable alternatives to, or may be used in combination with, antibiotics as effective mastitis therapeutic agents.

Animals↗
PubMed1992

Field trial to determine efficacy of an Escherichia coli J5 mastitis vaccine.

Efficacy of an Escherichia coli (O111:B4) J5 bacterin for preventing naturally occurring IMI and clinical mastitis was tested in a 2.5-yr field trial in a 225-cow commercial herd. Cows with odd-numbered identification were vaccinated, and cows with even-numbered identification served as unvaccinated controls for each lactation during the study. Immunizations were subcutaneous on the upper part of the rib cage just posterior to the scapula at drying off, 30 d after drying off, and at calving. Percentage of quarters infected at calving with Gram-negative bacteria did not differ between treatment groups. A total of 67% of Gram-negative bacterial IMI present at calving in control cows became clinical during the first 90 d of lactation compared with 20% in vaccinated cows. Rate of Gram-negative bacterial clinical mastitis was higher in control cows than in vaccinated cows during the first 90 d of lactation. Immunization with the E. coli J5 bacterin did not reduce level of Gram-negative bacterial IMI at calving but did reduce incidence of clinical mastitis.

Animals↗
PubMed1992

The economic implications of bioengineered mastitis control.

This paper estimates the cost of mastitis for the New York dairy sector. The average cost is found to be $125 per cow from reduced milk production, treatment, and increased culling. At the 1988 cow inventory, this translates to approximately $100 million annually for the entire dairy farm sector. When quality and production losses for the processing sector are added, the cost to the New York industry alone is nearly $150 million annually. Two promising new treatments, a bacteriocin and a vaccine, are evaluated. Both have shown effectiveness in preliminary trials against Staphylococcus aureus. Assuming that further development will allow the treatments to be effective against the major bacterial sources of mastitis infections, the treatments are projected to increase the annual income of the New York dairy industry by $18.8 to $39.7 million. The bacteriocin could replace antibiotic usage, a desirable goal in the opinion of many, and the vaccine promises to immunize cows against mastitis very effectively.

Animals↗