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1.
We collected samples of teat duct material and mammary secretion from ewes in three farms (flock A, polyparous n = 7; flock B, polyparous n = 6, primiparous n = 4; flock C, polyparous n = 4): 14 samples immediately after lambing (before sucking of lambs), 244 samples during the suckling period and 156 samples during the milking period. Conventional bacteriological techniques were used. The results were modeled using survival analysis, initially by the Kaplan–Meier method and then by the Cox Proportional Hazards method. Then, we calculated the minimum true risk of an “at-risk” teat or mammary gland being infected and analyzed these data with STATA using the GLLAMM program for Generalised Linear Latent and Mixed Models. During the suckling period, bacteria were isolated from 52 (21%) duct material and 19 (8%) secretion samples; respective results for the milking period were 20 (13%) and 9 (6%). There was an increased risk of duct rather than secretion samples being infected (P < 0.001). There was a significant difference among flocks in isolating bacteria from duct (P < 0.01) or secretion (P < 0.001) samples during suckling period, but not during hand-milking period (P > 0.4 and 0.1, respectively). There were no differences between isolation of bacteria from duct (P > 0.5) or secretion (P > 0.7) samples among primiparous and polyparous animals. Most bacterial isolates were staphylococci. Persistent isolation of the same bacterial species from duct material samples obtained from a particular ewe was recorded with five Staphylococcus spp. and two Mannheimia haemolytica isolates. The results indicate that infections of the teat duct can take place easily; however, not all infections result to infection of the mammary gland. The results support experimental evidence that defence mechanisms of the healthy teat are able to limit the infection. Maintenance of healthy teats contributes to effective defence mechanisms, and coupled with minimal infections of the teat duct, would contribute to the prevention of mastitis in ewes.  相似文献   

2.
A 2 × 2 factorial experiment was used to investigate the interaction between dietary crude protein (CP) concentration (200 vs 140 g/kg) and inulin supplementation (0 vs 12.5 g/kg) on nitrogen (N) excretion and intestinal microflora from 16 boars (n = 4, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high CP diets had a higher excretion of urinary N (P < 0.01), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased urine: faeces N ratio (P < 0.05) compared to the inulin free diets. There was no significant effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal E.coli. Pigs offered the diet containing 200 g/kg CP plus inulin decreased the population of E.coli compared to the inulin supplemented 140 g/kg protein diet. However, CP concentration had no significant effect on the population of E.coli in the unsupplemented diets. Inulin supplementation increased caecal bifidobacteria (P < 0.01) compared to the inulin free diets. In conclusion, inulin supplementation favourably altered N excretion and lowered the population of E.coli at high CP concentrations.  相似文献   

3.
Data from the Norwegian progeny testing program were used to examine the impact of milking characteristics and morphology of udder and teats on clinical mastitis in first- and second-lactation Norwegian cattle. The study was designed as a 1-1 matched case-control study with herd, parity, days in lactation and calving season as matching variables. Conditional maximum likelihood logistic regression was used to evaluate the effects of three primary (2 min milk, milk leakage and teat-end-to-floor distance) and six other study variables. Treatment records from the Norwegian health card system on acute and chronic clinical mastitis were used to define cases. The chosen model included 565 matched pairs. Significant risk factors of clinical mastitis were decreasing teat-end-to-floor distance (P = 0.02) and periparturient udder edema (P < 0.01).

Borderline effects were demonstrated by larger than herd-average teat diameter (P = 0.04), udder asymmetry (P = 0.05) and increasing 2 min milk (P = 0.08). Results were compared to a previous study on the same data with loge somatic cell count as the dependent variable. Inclusion of teat-end-to-floor distance in the genetic improvement scheme may increase the efficiency of genetic selection for mastitis resistance.  相似文献   


4.
The objectives of this study were to describe the prevalence and distribution of serum antibodies to Bluetongue virus (BTV) in a sample of 38 sheep flocks in northern areas of the North West Frontier Province of Pakistan and to identify demographic and productivity variables that are associated with BTV seropositivity. Blood samples were taken from a random sample of ewes in each flock in April 1995. The owners of the flocks were interviewed regarding some demographic, husbandry and productivity variables of the flocks on the day of blood sampling. A competitive enzyme-linked immunosorbent assay was conducted to test the serum samples for BTV group-specific antibodies. BTV seropositive reactions were obtained in 184 (48.4%) out of 380 tested sera, and in 89.5% (34/38) of the flocks. In the 34 seropositive flocks, the prevalences ranged from 12.5 to 100% (median = 47). A multivariable logistic analysis was carried out to study the influence of demographic and productivity variables on the BTV serological status of the sheep flocks. Abortion risk in the previous lambing season was mildly associated with the serological status of the flock (adjusted odds ratio = 1.16, P = 0.07). For the seropositive flocks, a linear multiple regression showed that distance travelled by the flock during transhumant movement was significantly associated with percent seropositivity (partial regression coefficient (± SE) = − 0.091 ± 0.045).  相似文献   

5.
The aim of the study was to determine the diagnostic value of measuring serum amyloid A (SAA) concentrations in milk of individual ewes and in farm bulk milk for monitoring udder health. Udder health was calculated by examining a randomly selected group of seven flocks at each farm visit by means of California mastitis test and bacteriological examination of 5749 milk samples. SAA was determined additionally in 267 randomly selected milk samples from six flocks. Thirty-one bulk milk samples from these farms were tested for SCC and SAA levels. Subclinical infections were detected in 29.5% of samples whereas no clinical infections were observed. Intramammary infected udder halves showed significantly elevated SAA concentrations (121.3+/-25.3 microg/ml) in milk compared to the levels of healthy udder halves (8.0+/-1.9 microg/ml; p<0.001). SAA was significantly elevated in sheep with elevated CMT scores and positive bacteriological results. Bulk milk SAA levels ranged from 18.6+/-6.7 to 37.4+/-14.1 microg/ml and showed a positive correlation with bSCC (r=0.38, p=0.018) but not with percent infected glands (r=0.022, p=0.453). This study demonstrated that SAA levels in milk can be used to detect subclinical mastitis in individual ewes whereas further investigations are needed to determine the value of measuring SAA in bulk milk for monitoring flock udder health.  相似文献   

6.
In a field investigation of 10 flocks in Southern Greece, 3367 dairy ewes were examined twice, in order to estimate the incidence risk and the aetiology of mammary abnormalities during the dry-period. Abnormal secretion, lumps, nodules, diffuse hardness, abscesses and cysts were the abnormalities detected. The cumulative incidence of mammary abnormalities during the dry-period was 5.1% (95% confidence interval: 4.4–5.8%); 47% of the cases detected developed during the first three weeks after cessation of lactation. Despite variation in the flock size, there was no between-flock variation in the risk of a ewe developing mammary abnormalities. Staphylococci (Staphylococcus aureus and coagulase-negative isolates) were the most frequently isolated bacteria from mammary samples; Actinomyces pyogenes, Clostridium perfringens, streptococci and Escherichia coli were also isolated. Resistance was encountered among the staphylococcal isolates.  相似文献   

7.
旨在探讨金黄色葡萄球菌（S.aureus）型和大肠杆菌（E.coli）型乳腺炎奶牛乳腺组织的炎症相关因子基因的mRNA转录水平。将105 CFU·mL-1的S.aureus和E.coli经乳导管分别注入奶牛乳房,在感染第7天采用活体无菌手术法采集乳腺组织,并采用组织HE染色和免疫荧光法进行乳腺炎模型的鉴定;利用qPCR分别检测了2个诱导组和对照组奶牛乳腺组织的趋化因子家族（CCL2、CCL8、CXCR1、CXCL2和CXCL13）、补体因子（CFI和CFB）、自噬调节因子DEPP1和白细胞介素受体IL21R共9个基因的mRNA转录水平。结果显示：与对照组相比,TLR4/NF-κB炎症相关信号通路中的关键分子（TLR4、NF-κB和TNFα）在2个诱导组乳腺组织中的蛋白表达水平均极显著上调（P<0.01）;结合HE染色结果,表明本试验成功构建了2种类型的奶牛乳腺炎活体模型。mRNA转录水平的检测结果表明,与对照组相比,7个基因（CCL2、CCL8、CXCR1、CXCL2、CFI、CFB和IL21R）在2个诱导组乳腺组织中的mRNA转录水平均极显著上调（P<0.001）,CXCL13的mRNA转录水平仅在S.aurues诱导组乳腺组织中极显著上调（P<0.01）;DEPP1的mRNA转录水平在2个诱导组中均极显著下调（P<0.01）。此外,CCL2、CCL8、CXCR1、CFI和IL21R共5个基因在E.coli诱导组中的mRNA转录水平均极显著高于S.aureus组（P<0.01）。S.aureus和E.coli感染均可导致奶牛产生严重的临床乳腺炎症状,并促使上述炎症相关基因的mRNA转录水平在乳腺组织中发生变化,以应对乳腺炎症的发生与发展过程;趋化因子CCL2等5个基因在E.coli诱导组中的mRNA转录水平显著高于S.aureus诱导组,解释了E.coli常常能引起急性乳腺炎,而S.aureus可引起慢性乳腺炎的原因。上述结果可为深入研究不同类型乳腺炎的分子调控机制提供参考。  相似文献   

8.
Rearing conditions and foot-pad dermatitis in Swedish broiler chickens   总被引：1，自引：0，他引：1  
A method of classification of broiler foot-health status was developed to estimate the prevalence of foot-pad dermatitis in Swedish broilers. Data on foot health were collected from 101 commercial broiler flocks at slaughter. The producers were asked to fill in a questionnaire on rearing conditions and equipment for every flock.

Lesions were commonly observed; only 62% of the birds were classified as being without lesions, 32% had mild lesions only (discoloration, erosions) and 6% had severe lesions (ulcers). Flocks reared in houses equipped with small water cups had significantly (P < 0.05) higher prevalences of foot-pad dermatitis than flocks reared with water nipples. Thick layers of litter, regardless of litter material, also resulted in significantly (P < 0.05) higher prevalences of foot-pad dermatitis than litter layers thinner than 5 cm.  相似文献   


9.
Previous research has reported evidence for negative effects of progestagens on follicular growth and oocyte competence. In the present study, negative effects of progestagens on follicular growth and oocyte developmental competence were assessed. During the breeding season, 20 Sarda ewes were treated with two doses of cloprostenol, 10 days apart, to assure the presence of a corpus luteum (CL). On day 5 after the second cloprostenol dose, 10 ewes were treated with a progestagen sponge while 10 females remained untreated. Starting on day 7 after the second cloprostenol dose, all the ewes were treated with 6 equal doses of 24 I.U. of FSH (Ovagen™, ICP, NZ), every 12 h. The number of follicles ≥2 mm in diameter increased (P < 0.0005) in all the ewes from 24 h before to 60 h after the first FSH dose (from 12.8 ± 1.1 to 23.4 ± 1.3 in treated and from 12 ± 0.6 to 22 ± 1.2 in untreated ewes, n.s.). There were no significant differences in follicle dynamics between groups, but concentrations of estradiol in control ewes were higher than in the progestagen group (P < 0.05). Twelve hours after the last FSH dose, oocytes were collected by ovum pick-up. Recovery rates were lower for progestagen-treated ewes (71.1 versus 83%; P < 0.001). After IVP procedure, cleavage rate was also lower in the progestagen group (39.1 versus 82.6%; P < 0.001). Furthermore, blastocysts output revealed that oocyte developmental competence was lower in progestagen group (17.3 versus 30.4%; P = 0.245), although differences were not significant. These results suggest deleterious effects from progestagen on oocyte developmental competence and set the basis for new protocols for in vitro embryo production.  相似文献   

10.
In a study of diarrhoeic and non-diarrhoeic livestock (cattle, pigs and sheep) from 50 farms in Trinidad, the prevalence of bacterial (Campylobacter, Salmonella, Yersinia and Escherichia coli), parasitic (coccidia, Cryptosporidium and enteric helminths) and viral (rotavirus) enteropathogens in faeces or rectal swabs was determined. Occurrence of the enteropathogens was tested for association with age, health status, animal species and mixed infections.

Of 423 diarrhoeic animals tested, Salmonella was isolated from 21 (5.0%), Campylobacter from 191 (45.2%) and Yersinia from three (0.7%), while the corresponding prevalence from 270 non-diarrhoeic controls was eight (3.0%) (χ2 1.19, P = 0.28), 119 (44.1%) (χ2 0.04, P = 0.85) and four (1.5%) (χ2 0.8, P = 0.39), respectively. Verocytotoxigenic E. coli and heat-labile toxin-producing E. coli were isolated from 51 (13.7%) and five (1.3%), respectively, of 373 diarrhoeic animals but the corresponding prevalence from 258 non-diarrhoeic animals was 39 (15.1%) (χ2 0.15, P = 0.7) and five (1.9%) (χ2 0.07, P = 0.8), respectively. Cryptosporidium oocytes were detected in 67 (16.5%) of 406 diarrhoeic animals and from 31 (12.1%) of 257 non-diarrhoeic animals (χ2 2.13, P = 0.15). For 147 diarrhoeic animals tested for coccidia, 64 (43.5%) were positive compared with 34 (37.8%) of 90 non-diarrhoeic animals (χ2 0.54, P = 0.49).

The prevalence of rotavirus infection was significantly (P 0.001, χ2 37.8) higher in diarrhoeic animals (39.9%, 112 of 281) than in non-diarrhoeic animals (13.4%, 26 of 194).  相似文献   


11.
A study was conducted on 207 lactating camels in six herds in Kenya to evaluate the California mastitis test (CMT) for the detection of intramammary infections (IMIs) caused by Streptococcus agalactiae and Staphylococcus aureus and to investigate the prevalence of both the pathogens in the camel udder. IMI with S. agalactiae was found in 12% of all camels sampled. IMI with S. aureus was present in 11% of all camels sampled. The herd-level prevalence of IMI varied between 0 and 50% for S. agalactiae and between 0 and 13% for S. aureus. Longitudinal observations over 10–12 months confirmed persistent infections for both pathogens. Observations in one herd suggested that camel pox was a contributing factor in spreading and exacerbating S. agalactiae udder infections.

The CMT had quarter-level sensitivities of 77 and 68% for S. agalactiae and S. aureus in camels, respectively. The CMT specificities were 91% for both the pathogens.  相似文献   


12.
This experiment was designed to study the complex of Lactobacillus rhamnosus fermented herbal and Bacillus subtilis on White Feather broiler immunity performance and impact of Escherichia coli infection.360 one-day-old broiler chickens were randomly divided into 3 groups with 4 replicates in each group and 30 chickens per replicate.The pretrial period lasted for 7 d,and the experiment lasted for 35 d.The chickens in the group Ⅰ(positive control group) and group Ⅱ(negative control group)were all only fed a basal diet,group Ⅲ was test group,by additive 1% fermented herbal preparations,groups Ⅱ and Ⅲ were intraperitoneal injection of 1 mL E.coli at 35 d,broiler mortality,immune organ index,cecalmicroflora content,immunoglobulin levels,IL-2 and IL-6 content were tested.The results showed that injection of E.coli caused massive death of chickens,group Ⅱtook up to 75.00%,it was significantly higher than groups Ⅰ and Ⅲ (P < 0.05),the mortality in group Ⅲ was significantly lower than group Ⅱ(P < 0.05),was only 23.33%.Injection of E.coli maked spleen index and thymus index of group Ⅱincreased significantly (P < 0.05),the spleen index and thymus index of groups Ⅰ and Ⅲ were no significant difference (P > 0.05).E.coli counts was significantly decreased after injectionin group Ⅲ (P < 0.05),but the number of intestinal Lactobacilli of group Ⅲ was significantly increased (P < 0.05),and inhibited the propagation of E.coli,the counts of E.coli in groups Ⅰ and Ⅲ were no significant difference (P > 0.05).At 42 d,the sIgA of the intestinal fluid in group Ⅲ were higher than that of groups Ⅰ and Ⅱ with 11.99% and 36.56%,respectively(P < 0.05).The serum IgG concentrations of group Ⅲ was higher than that of groupsⅠand Ⅱwith 14.68% and 28.15%,respectively(P < 0.05).At 42 d,the IL-2 content of group Ⅱ was the lowest,it was significantly lower than group Ⅲ(P < 0.05),the IL-6 of group Ⅲ was significantly lower than group Ⅱ(P < 0.05).  相似文献   

13.
A study was performed in 1997 to estimate the prevalence and to investigate the etiology of subclinical mastitis in Swiss dairy herds managed under guidelines of controlled organic farming. It was planned as a longitudinal study over a period of 1 year and included a stratified random sample of 152 certified organic farms and 1907 cows. Two farm visits (the first from June to October when cows were on pasture, the second from January to March when cows were confined to barns) were performed on each farm. At each visit, farm management and individual-cow data (with emphasis on milking procedures and udder sanitation) were recorded. California mastitis tests (CMTs) were performed on each udder quarter of all cows in lactation. Milk samples with CMT >1+ were submitted for somatic cell counting (SCC), bacteriological examination and to test for antibiotic susceptibility. The SCC and germ-cell counts of monthly bulk-tank milk samples were available through Dairy Inspection and Advisory Services and milk production data of 567 herd-book cows were available from breeding associations. Possible individual and environmental predictors of subclinical mastitis were identified using logistic models adjusted for clustering of the data at herd and cow levels. Data were analyzed separately for cows from 7 to 100 and from 101 to 305 days post partum. Prevalences of subclinical mastitis at the quarter level were 21.2% for lactation period 7–100 days and 34.5% for 101–305 days post partum. The geometric mean SCC in bulk-tank milk samples was 85.6×103 cells/ml. Samples at 7–100 and 101–305 days post partum were positive for Staphylococcus aureus in 16.0 and 7.4%, for coagulase-negative Staphylococci in 51.5 and 50.6%, for Streptococcus agalactiae in 0.0 and 0.8%, for other Streptococci in 19.4 and 15.6%, for E. coli in 1.0 and 0.4%, and for Corynebacterium bovis in 25.7 and 45.1%, respectively. Risks of subclinical mastitis increased significantly with increasing days post partum and advancing age of cow. Cows that were sampled when staying in alpine dairies had considerably higher risks of subclinical mastitis than cows staying in home barns. Significantly lower risks of subclinical mastitis were observed in farms where CMT was performed regularly as a control measure. Bacteria in milk from cows with mastitis exhibited antibiotic resistance at a comparable frequency as found previously in conventional farms.  相似文献   

14.
Six chicks (3–6 weeks of age) were taken randomly from each of 200 broiler farms in northern Jordan, these chicks were submitted for post-mortem and parasitological examinations. Seven Eimeria spp. were identified: E. acervulina, E. brunetti, E. maxima, E. necatrix, E. mivati, E. mitis, and E. tenella. Half (50%) of the farms surveyed had all six chicks infected, 23% of the farms were free of the infection. E. tenella was the most prevalent species (39%) followed by E. necatrix (12%), E. brunitti (12%), and E. maxima (10%). Prevalences did not vary by flock size. Also, neither the use of coccidiostat nor previous coccidiosis clinical outbreaks was associated with the prevalence of coccidiosis.  相似文献   

15.
Fifty randomly selected sheep flocks from a region in central Norway were sampled in December 1999 to determine the flock prevalence of Salmonella enterica subspecies diarizonae serovar 61:k:1,5,(7) (S. IIIb 61:k:1,5,(7)). From each flock, 15–41 rectal swabs were collected from individual sheep of different age groups and examined for S. IIIb 61:k:1,5,(7). Positive flocks were visited again in January–April and each time, rectal swabs from the same animals were collected and examined for this specific serovar. Seven flocks (14%; 95% CI 6.3–27%) were positive for S. IIIb 61:k:1,5,(7) in December; in all, 10 sheep out of the 1233 (0.8%) were positive at the first sampling. From the seven positive flocks, six, five, six, and nine animals were positive in January, February, March, and April, respectively. Of the total 21 individual sheep tested positive from January to April, 15 were >2 years old (ORex=3.26; 1.1–10.2). Six out of the seven positive flocks were large flocks (>117 ewes). Sharing of rams between flocks did not seem to be a risk factor for the presence of S. IIIb 61:k:1,5,(7) in a flock.  相似文献   

16.
We conducted a prospective observational study on clinical and subclinical mastitis in 30 commercial meat-producing sheep flocks from 2 regions of the province of Quebec, Canada. A total of 2792 ewes selected in late gestation were followed from lambing to weaning of lambs. The incidence of clinical mastitis for the total lactation period (average of 58 days) ranged among flocks from 0 to 6.6%, with a median of 1.2%. The most frequently isolated bacteria from the cases of clinical mastitis, in pure or mixed culture, were Mannheimia haemolytica (26%), Staphylococcus aureus (23%), and coagulase-negative staphylococci (17%). Incidence of clinical mastitis was higher in ewes that gave birth to 3 or more lambs and from the Estrie region, and was associated with an increase in ewe mortality, an increase in lamb mortality at the litter level, and a decrease in lamb's weaning weight for lambs born in multiple litter size or from ewes ≥4 years old.Among 354 selected ewes with clinically normal udder at the end of lactation, 28.8% had potentially pathogenic bacteria isolated from milk. The most prevalent bacteria were S. aureus (9.3%) and coagulase-negative staphylococci (9.3%). The risk of having a positive culture in at least one half was different between the two regions. Prevalence of ewes (n = 261) with California Mastitis Test (CMT) positive result in at least one half was 24.1 and 14.9% using a cut-off of ≥1+ and ≥2+, respectively. Prevalence of culture-positive udder halves was 11.7% for CMT-negative compared with 53.6% for CMT 3+ halves. CMT status was positively associated with the isolation of coagulase-negative staphylococci, M. haemolytica, S. aureus, and various Streptococcus species, but not with other isolated bacteria. Additionally, prevalence of CMT-positive halves was higher in ewes from the Estrie region, aged of ≥4 years versus 1 year, having clinical mastitis previously detected in the lactation and/or with low body condition score. Lamb weaning weight was associated with CMT status of ewes, while weaning weight was not associated with milk culture results. More research is needed to understand the dynamic of milk SCC and IMI in ewes from meat-producing flocks, its economical impact and best ways to control it.  相似文献   

17.
为探明牦牛隐性乳房炎（SCM）主要病原菌及其耐药和毒力基因的分布情况，本研究自甘肃省甘南州夏季牧场收集无乳房炎临床症状牦牛乳样，通过兰州乳房炎试验（LMT）筛选SCM乳样，从中分离病原菌并纯化培养，利用16S rDNA鉴定主要病原菌，通过纸片扩散法判定其药物敏感性，并采用PCR方法对相关耐药及毒力基因进行检测。结果显示，共筛选出牦牛SCM乳样324份，检出率14.43%；主要病原菌为葡萄球菌属、埃希氏菌属和肠球菌属，其中葡萄球菌分离株对青霉素和四环素耐药率最高，分别为59.57%和47.52%；大肠埃希氏菌分离株对四环素和氨苄西林耐药率最高，分别为43.40%和20.75%；粪肠球菌分离株对四环素和红霉素耐药率最高，分别为25.00%和16.67%；59株耐青霉素金黄色葡萄球菌中共检出MRSA 12株，其中7株携带mecA基因，5株含mecC基因；四环素外排泵基因tetK、tetA携带率最高（85.45%、56.36%），核糖体保护基因tetM携带率最低（34.55%）；毒力基因中，clfA、clfB、fib、coa基因检出率较高（87.64%、84.27%、83.15%、82.02%）。研究表明，牦牛SCM的主要病原菌为金黄色葡萄球菌和大肠埃希氏菌，均对青霉素类和四环素类抗生素耐药性较高，其中金黄色葡萄球菌的主要毒力因子为黏附因子和凝固酶。  相似文献   

18.
为了建立由金黄色葡萄球菌小菌落突变株(small colony variants,SCVs)诱发感染乳房炎动物模型,本试验取40只分娩6~8 d的BALB/c小鼠,随机分成8组(n=5),分别为阴性对照、生理盐水组和不同剂量金黄色葡萄球菌SCVs及金黄色葡萄球菌质控菌株(1.0×103、1.0×104、1.0×105 CFU/mL)试验组,对生理盐水组及各试验组小鼠第4对乳腺注射生理盐水和对应剂量的菌液(50 mL/只),注射后24 h解剖观察病理变化,一侧乳头制作石蜡切片,另一侧研磨后用ELISA检测试剂盒检测组织匀浆上清中的TNF-α含量。结果显示,注射菌液的试验组,小鼠均出现不同程度的临床症状,乳腺出现不同程度的炎性症状和病理变化。同一注射剂量下,金黄色葡萄球菌质控菌株较金黄色葡萄球菌 SCVs病理变化严重,通过SPSS等软件对试验数据进行统计分析后得出,高浓度处理组金黄色葡萄球菌质控菌株的TNF-α表达量极显著高于金黄色葡萄球菌SCVs(P<0.01)。结果表明,金黄色葡萄球菌及其SCVs均可用来建立小鼠乳房炎模型,且金黄色葡萄球菌SCVs引起的情况较其正常株轻微,这一结果为由金黄色葡萄球菌SCVs引起的奶牛慢性乳房炎的预防和控制及其致病机制的研究提供了新的材料和有益的探索,为SCVs与慢性乳房炎更深层次关系的研究奠定基础。  相似文献   

19.
Screening of subclinical mastitis under field conditions is done using the California mastitis test (CMT). CMT score of ≥1 corresponding to ≥500,000 somatic cells ml−1 is commonly used as threshold of subclinical mastitis in temperate countries. However, given the innately high physiological level of somatic cells in low yielding dairy cows, this threshold may not apply to low yielding dairy cows. The current study was undertaken to investigate the clinical utility of CMT for screening of Staphylococcus aureus subclinical mastitis in low yielding smallholder dairy cows in Tanzania. A total of 1151 of quarter-milk samples were CMT tested, of these 914-originated from cows with a lactation period of 14–305 days. All samples were screened for subclinical mastitis by the CMT as well as microbiological culture of single, duplicate (two consecutive) and triplicate (three consecutive) samples as a gold standard. For the duplicate and triplicate quarter-samples, cows were considered positive for S. aureus subclinical mastitis if results of microbiologic culture for S. aureus were positive for two of two, and for at least two of the first three consecutive quarter-milk samples collected from that cow, respectively. Using a CMT score of ≥1 would classify 78.6% of the 940 quarter-samples as positive. Eighty-two percent of the samples in which S. aureus was isolated had CMT scores ≥2; this would classify 51.6% of the 940 quarter-samples as positive. For the single sample, this cut-off had sensitivity, specificity and likelihood ratio for S. aureus of 0.87, 0.83 and 4.24, respectively. For the duplicate quarter-milk samples this cut-off had sensitivity, specificity, and likelihood ratio of 0.94, 0.86, and 5.19. While, for the triplicate quarter-milk samples this cut-off had sensitivity, specificity and likelihood ratio of 0.97, 0.92 and 7.47, respectively. Based on these results and practical considerations, it is concluded that CMT score of ≥2 corresponding to ≥800,000 somatic cells Ml−1 is the best cut-off to correctly identify S. aureus intramammary infections in low yielding dairy cows in Tanzania.  相似文献   

20.
The release of tumor necrosis factor-alpha (TNF-) from cultured bovine alveolar macrophages (BAM) was evaluated following stimulation of BAM with bovine herpesvirus-1 (BHV-1), parainfluenza-3 (PI-3) virus, bovine respiratory syncytial virus (BRSV), Escherichia coli 0111:B4 endotoxin, Pasteurella haemolytica type 1 endotoxin, Pasteurella multocida endotoxin, and virus/endotoxin combinations. A cytotoxic assay system using Georgia bovine kidney cells as targets was used to measure TNF- activity. The cytotoxic activity was neutralized by an anti-human TNF- monoclonal antibody.

Stimulation of BAM with 1 median tissue culture infectious dose (TCID50) of live or ultraviolet (UV)-inactivated PI-3 virus/cell resulted in release of TNF- in significantly (P<0.05) higher amounts than sham-induced BAM. The quantities of TNF- released after live or UV-inactivated BHV-1 or BRSV induction were not significantly higher than sham-induced BAM. E. coli 0111:B4, P. haemolytica type 1 and P. multocida endotoxins stimulated TNF- release in a dose-dependent manner. Sequential exposure of BAM to 1 TCID50 per cell of either live BHV-1, PI-3 virus or BRSV and then 5 μg ml−1 of either E. coli 0111:B4, P. haemolytica type 1 or P. multocida endotoxin caused a significant (P<0.05) reduction in detectable TNF- in seven of nine virus/endotoxin combinations tested, when compared with 5 μg ml−1 of endotoxin alone. Parainfluenza-3 virus/endotoxin combinations stimulated higher TNF- release when compared with other virus/endotoxin combinations. Five out of six test animals had serum-neutralizing antibodies to PI-3 virus, one out of six had serum-neutralizing antibodies to BHV-1, and two out of six had serum-neutralizing antibodies to BRSV, suggesting a possible relationship between serum neutralizing antibodies and TNF- release from in vitro cultivated BAM.  相似文献   


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