Mycoplasmal mastitis in dairy cows in the Moghan region of Ardabil State, Iran

Mycoplasmas are an important and economically significant cause of mastitis in dairy cows in various parts of the world. The organisms are highly contagious, with the main reservoir of infection originating from cows with subclinical mastitis. In 1998 the 1st cases of bovine mastitis due to Mycoplasma bovis were diagnosed in Ardabil State, Iran. An investigation was carried out with the aim of establishing the extent of mycoplasma infections in dairy cows in Ardabil State. Milk samples obtained from 80 cows with clinical mastitis were cultured in the laboratory for the presence of mycoplasmas. Similarly, 48 bulk-tank milk samples were examined for the presence of mycoplasmas. A modified Hayflick broth was used to isolate the mycoplasmas and an immunoperoxidase test used for the species identification of the isolates. Mycoplasma bovis was isolated from 39 (48.75%) of the clinical mastitis samples and from 48 of the bulk-tank milk samples tested. This indicated that mycoplasma udder infections were more prevalent in dairy cows in Ardabil State than previously thought.     

Studies of Mycoplasma mastitis in cattle. 6. Testing of Mycoplasma isolated from milk for udder pathogenicity

Strains of M. bovis, A. laidlawii, A. axanthum, and one unidentified strain of the family of mycoplasmataceae as well as altered secretion obtained from cows with mastitis were intracisternally applied in experiments and proved to be pathogenic to cattle udder. The results are likely to suggest the importance of mycoplasma isolated from the milk of mastitis cows to the aetiology of enzootic mastitis in three large dairy cattle stocks. Intravenous application of M. bovis and A. laidlawii caused neither mastitis nor mycoplasma secretion in the milk.     

Fungi isolated from bovine udders , and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources. METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi. RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats. CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi. CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance. KEY WORDS: Fungi, yeast, mould, bovine, intramammary infection, somatic cell count, mastitis.     

Serratia liquefaciens mastitis in a dairy herd

Serratia liquefaciens mastitis was detected and investigated in a 41-cow Holstein herd. Twenty cows were treated for mastitis over a 3-month period. Serratia liquefaciens was isolated from milk samples obtained from 8 of 12 cows tested during the epizootic. Results of an epidemiologic investigation suggested that extensive frostbite of the teats decreased the udder defense. Poor milking technique and hygiene were responsible for increased exposure of the damaged teats to potential udder pathogens. Treatment of each cow resulted in initial clinical improvement, but exacerbations occurred in 75% of the cows with documented S liquefaciens infections.     

Bovine mycoplasma mastitis from intramammary inoculation of small numbers of Mycoplasma bovis. I. Microbiology and pathology

Intrammary inoculation of 70 colony forming units (cfu) of Mycoplasma bovis into one quarter of four previously non-infected cows resulted in severe mastitis in inoculated and uninoculated quarters. Hematogenous spread of the infection was most likely, as mycoplasma was isolated from the peripheral blood of three of four cows and the milking machine was designed to prevent quarter to quarter communication of milk and air. The presence of large numbers of mycoplasma exceeding 10⁶ cfu/ml of milk preceded the onset of overt sero-purulent mastitis by 1–3 days. In general, the severity, duration of the infection and within cow spread of mastitis to adjacent quarters after the inoculation of 70 cfu was indistinguishable from naturally occurring mycoplasma mastitis.The pathology of the chronically infected quarters consisted of alveolar involution and moderate to severe mononuclear infiltration and an increase in interalveolar and loose connective tissue. The quarters of one cow resolving the infections at the time of slaughter were not as severely affected and contained numerous milk-producing alveoli and many alveoli with hyperplasia of the alveolar cells.     

Fungi isolated from bovine udders,and their possible sources

AIM: To identify fungi isolated from infections of the bovine mammary gland, and establish their possible sources.

METHODS: From a herd of 420 cows, milk samples were collected from all quarters at calving and cultured to detect causative organisms. Quarters identified as infected with fungi were further sampled during early lactation. Samples from feedstuffs, the feed pad and ends of teats were also collected and analysed for the presence of fungi.

RESULTS: Eleven of 420 cows were diagnosed with intramammary infections (IMI) caused by yeasts (nine cows, 10 quarters) and moulds (two cows, three quarters). Six of the yeast species had previously been reported as being responsible for mastitis. Elevated somatic cell counts (SCC) were observed in many quarters, but most infections were eliminated spontaneously. Two of the fungi isolated from milk samples were also isolated from feedstuffs and teat swabs, and seven other fungi isolated from milk samples were not isolated from feed, the feed pad or cows' teats.

CONCLUSIONS: Isolation of fungi from the udder is rarely reported in dairy cows in New Zealand. In this herd, contamination of the end of the teat originating from feedstuffs and possibly exacerbated by the use of a feed pad may have led to the establishment of IMI caused by fungi.

CLINICAL RELEVENCE: Fungi are infrequently if ever reported in mastitis trial data or surveys in New Zealand and are probably of little clinical significance.     

Nocardia mastitis in cattle. 1. Clinical observations and diagnosis in 7 particular cases

Lately reports of nocardial mastitis have been increasing. Therefore the clinical aspects of 7 individual cases were investigated. Pathologic-anatomical changes of the udder were registered and bacteriological examination of tissue and milk probes were performed. All of the cows had a mastitis during previous lactation periods which had to be treated with antibiotics. The infected quarters recovered in no cases. Shortly after parturition 6 cows had a severe acute mastitis. The cows were treated intramammarily and parenterally with various antibiotics during several days. The infected quarter became indurated and strongly enlarged. These changes were not influenced by therapy, and the cows lost weight. 14 days after the outbreak of the illness, all 6 cows were culled. One cow had a chronic Nocardia mastitis with involution of the affected quarter. Though treated several times, this cow did not recover either. The histopathological examination of the affected quarters revealed an acute to chronic, necrotic to granulomatous mastitis. Nocardia asteroides was histologically and bacteriologically proven to be the causative agent. The reason for the frequent infections with Nocardia and the way of infection is not clear yet. Therapy with antibiotics brought no recovery in any cases. The infected cows should be removed from the herd or culled.     

Clinical, bacteriological and therapeutic aspects of bovine mastitis caused by aerobic and anaerobic pathogens.

Twenty cows and three heifers with summer mastitis-like signs were included in the study. Forty aerobic and 38 anaerobic bacterial isolates representing 23 different species were isolated from udder secretions, the mean number of species being 3.4/sample. Pathogens most often were recovered in quantities exceeding 10(5) CFU/ml. Growth of pathogenic bacteria in the blood was found in only one case. Most cases occurred in housed animals and had often been preceded by teat injury. No anaerobic growth was found in milk samples of a control group consisting of 29 cows with ordinary acute mastitis. Values of indicators of inflammation in milk (NAGase and plasmin activity) were high, mean values being 914.1 and 1.3 units. The animals with aerobic/anaerobic mastitis were treated using various antimicrobial agents. All but three quarters were lost to milk production. Two animals with complete recovery were given a combination of penicillin G and tinidazole.     

Staphylococcus aureus variety hominis in a cattle herd

A site-linked hominis variety of Staphylococcus aureus was isolated from a cattle herd. The find coincided with accumulated occurrence of clinical mastitis in cows and the affliction of one milker with a nose furuncle. The origin of the strain was not elucidated. The same strain had been isolated throughout three years of observation from clinical and subclinical mastitis as well as from chronic udder affection of cows, but no extraordinary accumulation of clinically manifest mastitis had been observed. The hominis site variety was quite rare among Staphylococcus aureus strains isolated from other cow herds. Enterotoxin formation was recorded from strains of the hominis site variety and from strains which could not be coordinated with any other of the known site varieties and fell under crystal-violet Type A. No enterotoxin formation was recordable from the strains of the bovis variety. The same applied to the group of staphylococci of crystal-violet Type C which could not be coordinated either with any known site variety and which is assumed to have originated from the hominis site variety. The above findings do not support any conclusion as to whether the cows had been infected by the milker or vice versa.     

Prototheca zopfii mastitis in dairy herds under continental climatic conditions

In the last 2 years 223 cases of bovine mastitis caused by Prototheca zopfii infection were identified in 32 large-scale dairy herds. All of these farms were in Hungary, which has a continental type, temperate zone climate. Both the sporadic and epidemic forms of P. zopfii mastitis were observed. All the herds affected by the epidemic form had poor hygienic conditions and suffered from several managerial faults, but no specific predisposing factors could be identified. In almost all of the cases, the type II variant of this pathogen was isolated; however, the type III variant was isolated from three cows. The cows had a higher chance of new infection in the early weeks of lactation and in the summer. The P. zopfii infection usually resulted in a chronic subclinical, or mild clinical, inflammatory process in the udder, and was followed by a dramatic loss in milk production and a permanent increase in somatic cell count. The histopathological findings could be characterized as a progressive interstitial mastitis associated with alveolar atrophy. The self-recovery rate was very low.     

Mycoplasma infection as disposing factor to Streptococcus dysgalactiae mastitis

The authors studied a synergistic effect of an arginine hydrolising, but glucose negative mycoplasma strain (9293/3/2/1) and Streptococcus (Str.) dysgalactiae. Both agents, as mono-infections, caused only slight mastitis, but if the udder had been previously infected with mycoplasma, Str. dysgalactiae provoked very severe mastitis.     

An investigation of mastitis due to S agalactiae, S uberis and M smegmatis in a dairy herd

Subclinical mastitis caused by streptococcal infections affected 27 of 83 cows in a commercial dairy herd. Between three and six weeks after intramammary treatment of these cows with cloxacillin, 16 (59 per cent) of the treated cows developed acute clinical mastitis associated with Mycobacterium smegmatis. None of the untreated cows was affected. Infected quarters were moderately hypertrophied and fine clots were present in the milk for three to four weeks. No cows showed systemic signs of illness. Studies carried out over 12 months showed that infected cows shed M smegmatis for three to four months and affected quarters remained hypertrophied in all but one cow after 12 months. The mean milk cell count of affected quarters fell slowly from 4,850,000/ml in the acute stage to 810,000/ml five months later and 620,000/ml 12 months later, suggesting that the organism persisted in the udder. The estimated mean loss in lactation yield for cows with M smegmatis mastitis was 10.8 per cent. Losses were greatest when the hind quarters were involved (mean 28 per cent for cows with both hind quarters affected). Ten of the 16 affected cows were ultimately culled owing to serious reductions in yield.     

The course of mastitides in cows infected into the mammary gland with strains of Mycoplasma bovigenitalium and M. bovis]

Six cows were inoculated into the mammary gland with eight mycoplasma strains isolated from the genital tract of bulls and two type strains. The milk of cows infected with Mycoplasma bovigenitalium strains isolated from the genital tracts of bulls showed a change in the appearance and contained large quantities of mycoplasmas and specific antibodies. The mastitis was most intense in about 9 days and began to subside in 17 days infection. The type strain of M. bovigenitalium PG11 failed to produce mastitis. On the other hand, the type strain of M. bovis PG45 produced severe mastitis after a 14-day latency period, with the infection spreading to the uninoculated quarters, causing atrophy of the mammary gland, and persisting till slaughter. The sera of all cows that developed mastitis after experimental infection contained high titres of specific antibodies. The two infecting mycoplasma species were recovered from the inner organs and mammary glands of these cows after slaughter.     

Innate immune response in experimentally induced bovine intramammary infection with Staphylococcus simulans and S. epidermidis

ABSTRACT: Coagulase-negative staphylococci (CNS) are in several countries the most common bacteria isolated in subclinical mastitis. To investigate the innate immune response of cows to infections with two common mastitis-causing CNS species, Staphylococcus epidermidis and Staphylococcus simulans, experimental intramammary infection was induced in eight cows using a crossover design. The milk somatic cell count (SCC), N-acetyl-β-D-glucosaminidase (NAGase) activity, milk amyloid A (MAA), serum amyloid A (SAA) and proinflammatory cytokines interleukin (IL)-1β, IL-8, and tumor necrosis factor α (TNF-α) were determined at several time points before and after challenge. All cows became infected and showed mild to moderate clinical signs of mastitis. The spontaneous elimination rate of the 16 infections was 31.3%, with no difference between species. Infections triggered a local cytokine response in the experimental udder quarters, but cytokines were not detected in the uninfected control quarters or in systemic circulation. The innate local immune response for S. simulans was slightly stronger, with significantly higher concentrations of IL-1β and IL-8. The IL-8 response could be divided into early, delayed, or combined types of response. The CNS species or persistency of infection was not associated with the type of IL-8 response. No significant differences were seen between spontaneously eliminated or persistent infections.     

Efficacy of various treatment regimens, using liposomal streptomycin in cows with brucellosis

Thirty cows naturally infected with Brucella abortus were treated by various routes, using free or liposomal streptomycin or a combination of liposomal streptomycin and a long-acting oxytetracycline preparation. Of 21 cows treated with liposomal streptomycin alone, 3 (14%) were culture negative and 3 had 10 or fewer bacterial colonies isolated from tissues obtained at necropsy. Thirteen (62%) cows continued to shed organisms in udder secretions and were considered treatment failures. Of 9 cows that were given a combination of liposomal streptomycin and long-acting oxytetracycline, 5 (56%) were cured, 3 had 10 or fewer colonies on culture plates of tissue after necropsy and only 1 continued to shed B abortus in udder secretions after treatment. Eleven cows were given streptomycin liposomes by intramammary infusion with or without IM administration of long-acting oxytetracycline. The most effective regimen consisted of 2 intramammary infusions of streptomycin liposomes and 2 doses of oxytetracycline administered IM. Of 5 cows treated thusly, 2 were cured and all others had fewer than 10 B abortus colonies isolated from tissues obtained at necropsy.     

Serratia-mastitis in cows as a herd problem

Clinical mastitis with infection of Serratia marcescens occurred in a tied-up dairy herd in Sweden on a scale widely exceeding what has hitherto been reported in veterinary literature. The herd contained 37 milking cows before the disease period but only 14 at slaughter 21 months later in spite of some recruitment. A very large number of mastitis cases, usually rather mild and of short duration, had then occurred--during one single month not less than 47 cases. Hardly any cow escaped the disease. Instead, the single cows fell ill at short intervals with mastitis in the same quarter as previously or in another quarter. Antibiotic therapy in clinical cases, dry cow therapy and teat dipping had no obvious effect. Serratia marcescens was isolated in all 14 slaughtered cows in one or more quarters. The morphological changes were remarkably mild. Isolated Serratia strains revealed no distinctive marks compared with ordinary saprophytic strains in laboratory tests. Serratia-contaminated sawdust used as litter was possibly the source of infection and the milking machine possibly the tool for the transmission of bacteria to the udder, in the latter case by the aspiration of contaminated sawdust when the claw was attached or detached, or it fell off during milking. The pathogenicity of the bacteria and the susceptibility of the cows to udder infection may have been increased.     

IgG antibody response to Corynebacterium pyogenes,Peptococcus indolicus and microaerophilic cocci in natural and experimental mastitis

A mixed inoculum of C. pyogenes, P. indolicus and a microaerophilic coccus was used to induce experimental mastitis in two heifers. During the course of the infection, the IgG titres against these bacteria were monitored by the indirect immunofluorescent antibody technique. At the same time, the course of the infection was studied bacteriologically and by determination of clinical-chemical parameters. In both heifers, high titres of IgG against C. pyogenes, P. indolicus and the microaerophilic coccus were detected. The reactivity of the IgG towards surface-associated antigens of these bacteria seemed to reside mainly in the IgG2 subclass. Sera obtained from Denmark from heifers with experimental mastitis, which had been induced similarly, were also found to have significantly raised IgG titres against C. pyogenes and P. indolicus. Sera from naturally infected heifers and dry cows, from whose udder secretions C. pyogenes and P. indolicus had been isolated, were examined comparatively with sera from healthy heifers and dry cows, respectively, for the presence of IgG against these two bacteria. Statistically significant differences in IgG titres against both bacteria were demonstrated between pregnant heifers with mastitis and healthy pregnant heifers and between dry cows with mastitis and clinically healthy controls.     

Udder health in beef cows and its association with calf growth

Background

Studies outside the Nordic countries have indicated that subclinical mastitis (measured by milk somatic cell count or the California Mastitis Test), intramammary infections (IMI), or blind quarters in beef cows may have negative effects on beef calf growth. Knowledge on prevalence of such udder health problems in Swedish beef cows is scarce. Therefore, the main aim of this study was to investigate subclinical mastitis, IMI and udder conformation in a number of beef cow herds. Production of β-lactamase in staphylococci was also investigated. Associations between certain cow factors and subclinical mastitis and IMI, and associations between cow and calf factors and 200 day calf weaning weight were also studied. The herds were visited once within a month after calving and once at weaning. Udder examination and quarter milk sampling, for somatic cell count and bacteriology, were performed in 8 to 12 cows per herd and occasion.

Results

Approximately 50%, 40% and 10% of the cows had subclinical mastitis, IMI, and at least one blind quarter, respectively, but the prevalence varied markedly between herds. Intramammary infections (mainly due to staphylococci) were identified in 13-16% of the milk samples. Less than 5% of the staphylococcal isolates produced β-lactamase. Approximately 11% of the cows sampled twice had the same IMI (mostly Staphylococcus aureus) at both samplings. Cow factors of importance for subclinical mastitis and/or IMI were teat and udder shape, breed, parity, presence of blind quarters, and cow hygiene. No significant associations were found between udder health parameters studied and calf weaning weights.

Conclusions

Subclinical mastitis and IMI, but not blind quarters, were common in beef cows, but the prevalence varied markedly between herds. Most IMI were caused by staphylococci and more than 95% of those were sensitive to penicillin. Cows with large funnel-shaped teats or pendulous udder after calving, and cows with blind quarters were at risk of having subclinical mastitis and/or IMI. Poor hygiene was also a risk factor for udder health problems. No significant associations were found between udder health and calf weaning weight. More studies on risk factors are warranted to improve advisory services on awareness and prevention of mastitis in beef cows.     

Indurative lymphocytic mastitis in sheep after experimental infection with maedivisna virus

In order to provide further evidence for the association of an indurative lymphocytic mastitis in sheep with MVV (maedi-visna virus) infection, an experimental study was performed. Fourteen MVV-free pregnant ewes, 2 years of age, were divided into two groups. Eight were intravenously inoculated with MVV (strain ZZV-1050); six ewes served as sham-inoculated controls. Post-mortem examinations were carried out at 8, 16 and 28 months. After 8 months, the 3 infected ewes had indurated udders with extensive lymphoid proliferation around lactiferous ducts and in the acinar tissue. The ducts were often partially obliterated. After 16 months, one of the two infected ewes suffered from indurative lymphocytic mastitis. The other was free of specific udder lesions. After 28 months only one of three infected ewes had mild lymphocytic infiltration in the udder. None of the controls, two in each post-mortem session, had lesions typical of this form of mastitis. The lesions were most severe 8 months after infection. At 16 and 28 months lesions were of a lesser degree or were absent. The lung lesions in the infected ewes 8 months after inoculation were similar to the changes in the udder regarding the lymphoid accumulation, although the proliferation around bronchial tree and blood vessels was less pronounced. After 16 and 28 months all infected ewes had peribronchial and perivascular lymphocytic infiltration though of a lesser degree than after 8 months. From these results it is concluded that in addition to the lung and brain lesions MVV infections may cause a specific indurative lymphocytic mastitis.     

Cause, occurrence, and clinical signs of mastitis and anorexia in cows in a Wisconsin study

Microbiologic culture revealed the following cause of mastitis and anorexia in 145 cows in Wisconsin to be Escherichia coli, 66 cows; Klebsiella spp, 3; Corynebacterium pyogenes, 27; streptococci, 21; staphylococci, 20; yeasts, 1; and no bacterial growth, 7. Mastitis was detected with approximately equal frequency throughout the year. Escherichia coli was isolated throughout the year, but was more common and was the predominant organism during the summer. Corynebacterium pyogenes was isolated most often in winter and spring; streptococci in fall, winter, and spring; and staphylococci throughout the year. Corynebacterium pyogenes caused most of the mastitis in nonlactating cows. Escherichia coli, C pyogenes, streptococci, and staphylococci were isolated with about equal frequency at parturition, whereas E coli was the predominant cause of mastitis in early and late lactation. Of cases of mastitis, 27% were seen 10 days before and after parturition. Local and systemic clinical signs of infection were similar for all causes, except that C pyogenes caused more (P less than 0.01) malodorous and purulent milk than did other organisms and was isolated more commonly from quarters with injured teats. Recovery was significantly (P less than 0.01) higher in cows with E coli infections, compared with recovery in cows with gram-positive organism infections. Cows with C pyogenes infections frequently had quarters that ultimately ceased lactation. A few cows were recumbent at initiation of antimicrobial therapy and a few were not eating 24 hours later; however, 50% of these cows recovered. Criteria such as season of year, stage of lactation, appearance of milk and udder, and appetite permitted the cause (gram-negative or gram-positive organisms) of the mastitis to be predicted with 77% accuracy.