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1.
The study was undertaken to determine the aetiology and prevalence of mastitis in hand-milked cows (n = 186) in two major Ethiopian dairies. The California Mastitis Test and culturing for bacteria revealed that 21.5% of the cows were clinically infected and 38.2% had subclinical mastitis. Most mastitis pathogens isolated from milk samples testing positive by the California Mastitis Test were Gram-positive cocci. Staphylococci constituted 57% of the isolates, of which the predominant cause of bovine mastitis was Staphylococcus aureus (40.5%). Other mastitis pathogens isolated include streptococci (16.5%), coliforms (9%) and corynebacteria (5%). Retrospective analysis of farm records indicated that mastitis was the second most important cause of culling and accounted for 27% of the cows removed from these two dairies.  相似文献   

2.

Mastitis may be caused by a wide range of microorganisms able to induce distinct lesions in mammary tissues. This study aims to characterize the gross and microscopic features of mastitis in dairy cows and to correlate them with the pathogens involved. The udders of slaughtered dairy cows were inspected and milk samples from each mammary quarter or fragments of the parenchyma were sent for microbiological analysis, and tissue collected for histopathological evaluation. A total of 148 cows and 592 mammary quarters were collected. From these, 432 quarters (73%) had mastitis and in 160 (27%), no changes were observed. Mastitis was classified into seven patterns based on the histopathological findings, of which mixed, lymphoplasmacytic, and suppurative mastitides were the most prevalent with 35.9% (155/432), 27.1% (117/432), and 14.3% (62/432) of the cases, respectively. These patterns were associated with the same set of pathogens: Streptococcus spp., coagulase-negative Staphylococcus (CNS), Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis, and Corynebacterium bovis. The pyogranulomatous pattern represented 7.2% (31/432) of the cases with distinct distribution based on the agent involved, mostly S. aureus and Nocardia sp. Abscedative mastitis accounted for 6.0% (26/432) of the cases; it was characterized by multiple abscesses in the parenchyma and was mainly caused by Trueperella pyogenes. Necrosuppurative mastitis represented 5.8% (25/432) of the cases which were characterized by severe parenchyma necrosis and were caused by bacteria such as CNS and Escherichia coli. The granulomatous pattern represented 3.7% (16/432) of the cases and was occasionally associated with Mycobacterium sp.

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3.
Mastitis caused by Prototheca spp or Nocardia spp is considered to be difficult to treat. Both microorganisms are contaminants commonly found in soil. The occurrence of mastitis caused by these agents was studied in a particular dairy farm. In this herd, the animals were kept at pasture overnight and during daytime were brought to a pen where they were fed. This pen accumulated mud and faeces, particularly in the rainy season. During milking, pre-dipping of the teats was performed with an iodide solution, but they were not washed, so a layer of soil and faeces remained which may have contaminated the milking equipment. The herd comprised 91 lactating animals and 47 dry cows. For microbiological examination, 107 milk samples were collected from lactating cows and 186 samples of mammary secretions from the dry cows. Prototheca spp were isolated from 14.55% of the milk samples and Nocardia spp from 4.55%. Prototheca spp were isolated from 8.06% of the secretion samples from dry cows and Nocardia spp were isolated from 2.15% samples. The high occurrence of mastitis due to these environmental agents reflects the problem of keeping animals in muddy pastures and pens, and the defective pre-milking hygiene for the teats.  相似文献   

4.
AIM: To identify and enumerate colony forming units (cfu) of mastitis pathogens in bulk tank milk (BTM) from pasture-fed New Zealand dairy cows in the Waikato region.

METHODS: BTM samples from seven seasonal-calving dairy herds in the Waikato region were collected monthly from August to December 2004 (cows calved during July-September). Milk samples were cultured on blood aesculin and MacConkey agar plates for 24 h, and the number of mastitis pathogens identified and counted.

RESULTS: Colonies identified in BTM included aesculinpositive streptococci, Staphylococcus aureus, coagulase-negative staphylococci (CNS), and coliforms; counts ranged from zero to >1,000 cfu/ml. Counts >1,000 cfu/ml for total aesculin-positive streptococci, CNS and coliforms were present in 48%, 51% and 11% of BTM samples, respectively. Counts of Staph. aureus ranged from zero to 1,000 cfu/ml, but first appeared in BTM samples only in October. Staphylococcus aureus was repeatedly isolated in BTM from 4/7 farms during the testing period.

CONCLUSIONS: Counts of mastitis pathogens in this study appeared high relative to interpretive criteria set by other workers, which may indicate a high prevalence of mastitis risk factors on these farms. Interpretation of results is difficult as aesculinpositive streptococci, CNS and coliforms can be isolated from the environment as well as from cows with clinical or subclinical mastitis. Furthermore, Staph. aureus is inconsistently excreted from infected bovine mammary glands. More extensive study of this method is required in New Zealand to attempt to further validate the interpretation of results of bacterial culture of BTM.

CLINICAL RELEVANCE: This method may be used to monitor challenge from mastitis pathogens over time as part of milk quality control programmes. The technique may be of use as a screening test to provide information to veterinarians, affording them the opportunity to have an input into mastitis control on dairy farms in New Zealand.  相似文献   

5.
Signs of severe otitis media in 20% of dairy calves on one farm were associated with Mycoplasma bovis infection, based on isolation from the external ear canal and nares. Affected calves seroconverted to M. bovis and no other significant bacteria were isolated. Infection was considered likely to have originated from cows in the milking herd based on evidence of seroconversion and detection of infection in a milk sample. M. bovis infection should be considered when investigating otitis problems in calves.  相似文献   

6.
Mastitis-induced ovarian abnormalities were studied in a field trial. At 1-3 day after calving, > or = 2 parity cows not affected with chronic recurrent mastitis and yielding < 400,000/ml somatic cell count (SCC) individual milk in the previous lactation, were enrolled in the study. Thereafter milk samples were collected three times weekly for 95-100 day for progesterone (P4) assay. Individual P4 profiles were used to monitor ovarian cyclicity. When mastitis was diagnosed in the first 80 day post-partum (pp), clinical signs were recorded and scored, and aseptic milk samples were taken to identify the mastitis pathogens. Depending on the isolated pathogens the cows were blocked into one of the three sub-groups affected by either Gram-positive (GP), or Gram-negative (GN) bacteria, or of those with no detected pathogens (NDP). Cows suffering from any type of mastitis between days 15 and 28 (n = 27) showed a delay in the onset of ovarian cyclicity, and estrus was postponed compared to cows affected during the first 14 day pp (n = 59) and controls (n = 175) (38.6 +/- 2.3 vs 33.4 +/- 2.1 and 32.0 +/- 1.0 day, respectively, for onset of ovarian cyclicity and 90.7 +/- 2.5 vs 80.2 +/- 2.8 and 83.9 +/- 2.1 day, respectively, for estrus; both p < 0.05). The percentage of cows ovulating by day 28 was lower in those affected by mastitis between days 14 and 28 compared to cows between days 1 and 14 and controls (22.2% vs 47.5 and 50.3%, respectively; p < 0.05). A significantly higher rate of premature luteolysis was observed in GN + NDP compared to GP mastitis and healthy cows (46.7% vs 8.3 and 2.0%, respectively; p < 0.001). If the mastitis outbreak occurred during the follicular phase, the duration of this cycle segment was lengthened in GN + NDP mastitis compared to GP mastitis and healthy cows (10.8 +/- 0.9 vs 7.9 +/- 0.1 and 7.2 +/- 0.1, respectively; p < 0.001). The results indicate that mastitis can affect the resumption of ovarian activity in pp dairy cows. Mastitis may also impair reproduction also in cyclic cows: this effect can be the consequence of premature luteolysis or a prolonged follicular phase.  相似文献   

7.
A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

8.
Findings of herd investigations of heifers with prepubertal mastitis are presented. Mycoplasma bovis was isolated from lacteal secretions and tissue samples of necropsied heifers; the same strain infected dams and herd mates. Vertical transmission is suggested in this first report of intramammary infections of M. bovis in peripubertal heifers.  相似文献   

9.
Bovine mastitis, caused by Prototheca bovis, has received much attention worldwide. To investigate the status of P. bovis infection in dairy farms of Hubei, we collected 1,158 milk samples and 90 environmental samples from 14 dairy farms of Hubei, China. The isolates were identified with traditional biological methods and molecular biological techniques, and their pathogenicity was tested through mice infection experiments. Isolates from 57 milk and 20 environmental samples were identified as P. bovis. The mice infection tests proved that the isolated P. bovis could cause mastitis in mice, manifesting as severe red swelling of the mammary glands. Histopathological analysis of tissue sections showed necrosis and nodules lesions formed in the infected mice mammary tissue, accompanied by macrophage and neutrophil infiltration. These results suggested the existence of pathogenic P. bovis in dairy farms of the Hubei province, China, with brewer’s grains and fresh feces possibly playing important roles in the spread of this disease.  相似文献   

10.
The clinical, epidemiological and pathological aspects of protothecal mastitis in a Brazilian dairy herd are described. Prototheca zopfii infection was diagnosed in 11 of 121 milking cows. Clinical mastitis refractory to usual therapy was observed in 7 cows. Several environmental conditions conducive to the growth of Prototheca spp., such as wetness, muddiness and the presence of organic material, were present in the dairy. Improper milking practices and insanitary infusion of the intramammary antibiotics were also observed. Six cows with protothecal mastitis were slaughtered and the affected quarters of each cow were examined by histology and immunohistochemical staining for bovine keratin and P. zopfii. The histological lesions were characterized by interstitial infiltrates of macrophages, plasma cells and lymphocytes; algae were seen in the alveolar lumen and interstitium. The lack of a positive reaction with an antiserum against bovine keratin in the mammary alveolar epithelial layer in some affected areas suggests destruction of milk-producing tissues, which may be related to the low milk production observed. The algal organisms stained positively with a polyclonal antibody against P. zopfii.  相似文献   

11.
Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case–control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0–0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.  相似文献   

12.
The present study assessed the effects of intramammary infusion of Bifidobacterium breve (B. breve) on mastitis‐causing pathogens and on the somatic cell counts (SCC) in lactating cows with chronic subclinical mastitis. The bacteriological cure rates of 42 quarters from 42 cows infected with Staphylococcus aureus, Corynebacterium bovis, coagulase‐negative staphylococci, and environmental streptococci were 18.2% (2/11), 14.3% (1/7), 58.8% (10/17), and 28.6% (2/7), respectively, on day 14 after B. breve infusion. In a second trial, B. breve was infused into 18 quarters from 18 cows with chronic subclinical mastitis from which pathogens had not been isolated; the rates of quarters showing SCC > 50 × 104 cells/ml prior to B. breve infusion that decreased to < 30 × 104 cells/ml after infusion were significantly (p < .01) increased to 61.1% (11/18) on day 14 compared to that prior to infusion (0/18). The intramammary infusion of B. breve appears to be a non‐antibiotic approach for elimination of minor pathogens and decreasing SCC in quarters with chronic subclinical mastitis in dairy cows.  相似文献   

13.
Using deletion typing technique, five mycobacteria isolated from unpasteurised milk samples from cows in north-central Nigeria were characterized as Mycobacterium bovis (n = 4) and M. africanum (n = 1). This report emphasizes that transmission between the animal and human reservoir is a serious threat in Nigeria.  相似文献   

14.
AIM: To estimate the incidence of clinical mastitis and the frequency of isolation of mastitis-causing organisms from clinical cases in one lactation season (July 2005 to May 2006) on 14 dairy farms from the Northland region of New Zealand.

METHODS: Cases of clinical mastitis were determined by trained farm personnel who recorded the identity of affected cows. Pooled milk samples from affected quarter(s) were aseptically collected by the farm personnel, for microbiology. Mean numbers of affected cows and quarters were compared at the population and farm level per 305 cow-days-at-risk (DAR).

RESULTS: One or more cases of clinical mastitis occurred in 559/3,765 (14.8%) lactating cows. The average incidence of clinical mastitis was 0.19 cases per 305 DAR. The incidence in rear quarters (56.2%) was 1.3 times (p=0.027) that of front quarters (43.8%). The incidence of clinical mastitis and numbers of affected quarters were signifi cantly infl uenced by the stage of lactation (higher in early lactation), age (higher in older cows) and farm. At the cow level, the most common isolates were Staphylococcus aureus (23.7%) and Streptococcus uberis (23.3%). No causative organisms were identifi ed in 19.9% of the samples. Each cow had an average of 1.8 quarters affected during a case of clinical mastitis.

CONCLUSIONS: This study demonstrated a higher incidence of staphylococcal clinical mastitis on dairy farms from Northland than has been reported in other regions of New Zealand.  相似文献   

15.
Listeria monocytogenes was isolated from the milk of two cows and two sheep with mastitis in one quarter and one udder half. The animals were observed over a period of 2-12 months. Clinical examination of the udder, bacteriological examinations and determination of somatic cell counts of milk samples were performed monthly. All four cases suffered from a subclinical mastitis characterized by an elevated somatic cell count (0.8-10.1 x 10(6) cells/ml), a persistent shedding of Listeria and by a normal appearance of the milk. The animals did not show any systemic reaction, but all animals developed an atrophy of the infected mammary gland. Histological examinations revealed a chronic interstitial mastitis with diffuse infiltration of lymphocytes, plasma cells and macrophages. All internal organs showed no abnormalities, no Listeria could be isolated. Listeria could however be isolated from the affected mammary parenchyma and from the mammary lymph node. The results of the bacteriological examination could be confirmed by means of PCR. Using PFGE, all the isolates from the same animal were identical. Immunohistochemical examination of the ovine mammary glands achieved a very strong immunoreactivity for CD5 cells. The mode of infection and the reaction of the immune system's defense of the ovine udders are discussed.  相似文献   

16.
Objective To determine the prevalence of mastitis pathogens in high‐producing intensive dairy herds in New South Wales. Design Field survey. Procedure Milk samples from the mastitis‐affected quarter were collected from cows on five high‐producing dairy farms in NSW. The 820 samples were cultured using standard microbiological culture techniques. Results Bacteria or fungi were isolated from 83.3% of samples (683/820). More than two colony types were isolated from 16.7% of samples (137/820), two types from 6.6% (54/820), and one type from 52.3% (429/820). No bacteria were isolated from 24.4% (200/820) of the primary cultures, but enrichment cultures of these samples yielded single colony type bacterial isolates from 36.5% (73/200) of samples. Environmental pathogens, including coliforms, environmental Streptococcus and Staphylococcus spp., made up 91% (555/610) of isolates and accounted for 33.6% (205/610), 41.6% (254/610) and 15.7% (96/610), respectively, of isolates. Escherichia coli accounted for 76.1% (156/205) of the coliform isolates, Streptococcus uberis and Streptococcus dysgalactiae accounted for 32.3% (82/254) and 28.0% (71/254), respectively, of the environmental streptococcal isolates. Contagious pathogens were uncommon, comprising only 2.5% (15/610) of the total isolates. Conclusion The incidence and causes of mastitis are largely influenced by farm management. The relatively high prevalence of coliform mastitis in the intensive high‐producing herds in this survey contrasts with the low incidence reported in surveys of pasture‐based herds in Victoria. If the Australian dairy industry continues its current trend of intensification, coliform intra‐mammary infections may emerge as an increasingly important cause of mastitis.  相似文献   

17.
Mycoplasma bovigenitalium was isolated from milk samples from 16 of 99 cows on one farm during a 15-week period in the summer of 1986. One cow was severely affected, four cows had relatively mild signs of mastitis, and three had only altered dry-cow udder secretions. Eleven of the infected cows were dry and three had been calved less than 48 hours. The abrupt method of drying-off and improvements in cleaning of the milking equipment were introduced, but no other control measures were instituted to eradicate the mycoplasma infections. After this mild outbreak of mastitis the herd was monitored for the next 17 months. In total 19 cows had a mycoplasma isolated from udder secretions. Acholeplasmas were isolated from 14 cows but were not associated with clinical mastitis. The udder infections with mycoplasmas apparently resolved without resorting to the segregation and culling of infected animals.  相似文献   

18.
The objective of this research is to determine whether intramammary antibiotics with complementary acupuncture can reduce bovine mammary inflammation due to subclinical mastitis. Lactating cows were selected based on milk with a somatic cell count (SCC) greater than 500,000 cells/ml. Pre- and post-treatment milk samples were collected to determine SCC, aerobic bacterial content, milk ion conductivity, total protein, lactate dehydrogenase (LDH) and N-acetyl-beta-D-glucosaminidase (NAGase) concentrations. Milk serum was prepared from milk samples by double centrifugation. Concentrations of LDH and NAGase were determined using commercial enzyme-linked immunosorbent assays. Cows being treated with intramammary antibiotics were separated by random assignment to the acupuncture group (n = 10) and a no-acupuncture (control) group (n = 9). Both the acupuncture and control group were restrained for 30 min in a head catch 12 hr apart for a total of four times. For front quarters affected by subclinical mastitis, the acupuncture points used were spleen (SP) 12, SP 17, SP 18, SP 21, stomach (ST) 18 and conception vessel (CV) 12. For rear quarters affected by subclinical mastitis, the acupuncture points used were bladder (BL) 30, BL 30-1, BL 49, kidney (KI) 10, conception vessel (CV) 2 and CV 3. All parameters were compared using a Student t test. Significance was defined as p < .05. Compared to control cows, complementary acupuncture treatment reduced NAGase enzymatic activity in quarters of cows with subclinical mastitis. The reduction in NAGase suggests that complementary acupuncture treatment may be associated with healing of the damaged mammary epithelial cells, which are the primary source of NAGase activity in milk serum.  相似文献   

19.
The German wasp, Vespula germanica has been observed to injure teats of dairy cows, causing lesions that are associated with clinical and subclinical mastitis. The presence of skin lesions on the teats, caused by the wasps, was recorded in a dairy cattle herd located in the Samaria foothills during July–October 1999. Wasp‐inflicted injuries were found in 43.6% (58 of 133) of the adult cows and 1.4% (one of 71) of the first‐calving cows. They were located in 42.4% of cows (n = 25) on all quarters, 18 cows (30.5%) had lesions on the front quarters and 27.1% (n = 16) of cows on the hind quarters only. Clinical and subclinical mastitis were diagnosed in 61% (36 of 59) and 28.8% (17 of 59), respectively, of the injured adult and first‐calving cows. The most common bacterial isolates from the mastitic cows were Staphylococcus aureus 45.1% (n = 14), Streptococcus dysgalactiae 16.1% (n = 5), Streptococcus spp. 19.4% (n = 7) and others 13.9% (n = 5). The loss of milk production was estimated at 300 kg milk for each cow injured by wasps and exhibiting clinical mastitis. An increase in the bulk‐milk somatic cell count, from 186 × 103 at 1 month prior to the outbreak to a peak of 1200 × 103 in the post‐outbreak month, was noted. The culling rate reached 13.6% (eight of 59) of the affected cows. In summary, the considerable economic losses caused by the wasp infestation resulted from decreased milk production and a decline in milk quality, culling of affected cows, and increased demand for use of drugs and veterinary care.  相似文献   

20.
An indirect ELISA was used to detect antibodies to Mycoplasma bovis in milk samples collected from a herd with M bovis mastitis. Antibodies were detected in samples from nine cows which had developed clinical M bovis mastitis. Milk from only three consistently antigen-negative cows tested positive for M bovis antibodies. These results indicate the potential value of the indirect ELISA for the detection of cows which have recently developed M bovis mastitis during the early stages of an outbreak.  相似文献   

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