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1.
The objective of this study was to evaluate the relationship between bacterial species-specific virulence factors (VFs) present in the uterus at 3 different stages of lactation (1-3, 8-10, and 34-36 days in milk (DIM)) and the incidence of metritis and clinical endometritis in dairy cows. The following VF genes were investigated: plo (pyolysin), cbpA (collagen-binding protein), and fimA (fimbriae expression) which are Arcanobacterium pyogenes specific; fimH (a type 1 pilus component), Escherichia coli specific; and lktA (leukotoxin), Fusobacterium necrophorum specific. Uterine swabs were collected from 111 postpartum dairy cows. PCR was used to detect the presence of plo, cbpA, fimA, fimH, and lktA genes. A. pyogenes cbpA was detected in only 5 samples and therefore was not subjected to further analysis. E. coli (fimH) was significantly associated with metritis and endometritis when detected at 1-3 DIM; F. necrophorum (lktA) was significantly associated with metritis when detected at 1-3 and 8-12 DIM and with endometritis when detected at 34-36 DIM; and A. pyogenes (fimA and plo) was associated with metritis (fimA) when detected at 1-3 DIM and endometritis (fimA and plo) when detected at 8-10 and 34-36 DIM.  相似文献   

2.
A study was conducted to measure concentrations of potentially active ceftiofur derivatives, in plasma, in uterine tissues (endometrium and caruncles) and in uterine secretions at different time points after a single subcutaneous administration of ceftiofur hydrochloride (Excenel RTU Sterile Suspension) at the dose of 1 mg/kg body weight in Holstein-Friesian dairy cows. The animals (n=4) were injected within 24 h of calving, after expulsion of the foetal membranes. Plasma, lochial fluid, caruncles and endometrium were collected before ceftiofur hydrochloride administration and at 1, 2, 4, 8, 12 and 24 h after treatment. For each cow the concentrations of ceftiofur in the biological matrices were quantified using an high-performance liquid chromatography (HPLC) assay. The limit of quantification of the method was 0.1 microg/mL for plasma and 0.1 microg/g for lochial fluid, caruncles and endometrium. The concentrations of potentially active ceftiofur derivatives detected in plasma reached a maximum of 2.85 +/- 1.11 microg/mL at 2 h and decreased to 0.64 +/- 0.14 microg/mL at 24 h after administration. In lochial fluid, these concentrations reached a maximum of 0.97 +/- 0.25 microg/g at 4 h and decreased to 0.22 +/- 0.21 microg/g at 24 h after administration. In endometrium, these concentrations reached a maximum of 2.23 +/- 0.82 microg/g at 4 h and decreased to 0.56 +/- 0.14 microg/g at 24 h following the injection, whereas these levels in caruncles were 0.96 +/- 0.45 and 0.60 +/- 0.39 microg/g obtained at 8 and 24 h, respectively. At the dose of 1 mg/kg body weight in healthy dairy cows, subcutaneous administration of ceftiofur (as ceftiofur hydrochloride) after parturition results in concentrations of ceftiofur derivatives in uterine tissues and in lochial fluid that exceed the reported minimal inhibitory concentrations (MICs) for the common pathogens (Escherichia coli, Fusobacterium necrophorum, Bacteroides spp., and Arcanobacterium pyogenes) associated with acute puerperal metritis.  相似文献   

3.
The objective of this study was to estimate the effects of clinical mastitis (CM) (both with and without specific pathogen identification) occurring in different stages of lactation on length of herd life in two New York State dairy farms. The 2,697 cows in the study were followed for one lactation (the first-occurring one on or after 1 October 1999), until it ended because of a new lactation, culling, or end of study (31 March 2001 in one farm; 31 July 2001 in the other). A Cox proportional hazards model with time-dependent covariates, in SAS((R)), was used to measure, within a lactation, the effect of the first occurrence of CM (without specific pathogen identification) occurring 1--7, 8--66, 67--100, 101--225, or >or=226 days in milk (DIM), on how long cows remained in the herd. For the first occurrence of CM due to Streptococcus spp., Staphylococcus aureus, Staphylococcus spp., Escherichia coli, Klebsiella spp., and 'no pathogen isolated', the intervals were before and after the median DIM of first occurrence of each pathogen. There were too few cases due to Arcanobacterium pyogenes, and 'other pathogens grouped together' to split into intervals, so they were modeled as binary variables, i.e. as they occurred. CM was modeled using time-dependent covariates, to account for its differing effects throughout lactation on culling. Other variables controlled for were herd, parity, calving season, and other significant diseases. In the dataset, the lactational incidence risk of the first occurrence of CM was 18.2%; 20.0% of the cows did not survive the lactation that was studied. The overall annual culling percentage for both herds during the study period (including all cows, whether eligible for the study or not) was 35.6%. For cows with CM without pathogen identification, their highest hazard ratio (HR) of culling occurred from 67 to 100 DIM. All of the pathogens modeled markedly reduced herd life. On average over the entire lactation, cows with Staphylococcus spp. CM had the highest HRs for culling, although there were no significant differences among pathogens (at p=0.0018 (reflecting 28 pairwise comparisons)). For early-occurring (before median DIM of first occurrence) S. aureus CM, the daily rate of change of the HR of culling increased over time. The HRs for culling were particularly high for late-occurring (after median DIM of first occurrence) E. coli and Klebsiella spp. CM early in the interval, but the daily rate of change of the hazard of culling for these two pathogens decreased sharply over time. Treating CM as time-dependent therefore allowed us to measure in greater detail, its varying effects (of when it occurred) on herd life.  相似文献   

4.
This study compares cytobrush and lavage techniques for the assessment of endometrial cytology (EC) in clinically normal postpartum dairy cows. The EC samples were collected from Holstein cows (n = 35) during visit 1 (V1) at 20 to 33 d in milk (DIM) and 2 wk later during visit 2 (V2) at 34 to 47 DIM by using both techniques. A minimum of 100 cells were counted to determine the percentage of cells that were neutrophils (%PMN). The mean %PMN was significantly different between the techniques at V1 (P = 0.001), but not at V2 (P = 0.474). Overall, the %PM N decreased with time postpartum (r2 = 0.36; P = 0.001), but not within V1 (P > 0.05) or V2 (P > 0.1). Uterine diameter was negatively correlated with fluid recovery by the lavage technique (r2 = 0.41; P = 0.002). The mean %PMN was not influenced by the volume of fluid recovered in successful attempts, but 17% (12/70) of attempts yielded no fluid. In conclusion, the cytobrush technique is a consistent and reliable method for obtaining endometrial samples for cystologic examination from postpartum dairy cows.  相似文献   

5.
Forty-six indigenous Sanga-type (Nkone and Tuli breeds) cows and 46 crossbred (Nkone x Jersey and Tuli x Jersey) cows were randomly allocated to four treatment combinations in a 2 x 2 factorial arrangement with two breeds and two dietary levels, a control diet and a diet supplemented with dairy meal containing 14 per cent crude protein at the rate of 2 kg per cow per day. The progesterone concentration was measured in milk samples taken three times a week from 10 days postpartum for up to 200 days, and the cows' bodyweights and body condition scores were recorded fortnightly. The pregnancy rate in the crossbred cows was significantly higher (P<0.05) than in the indigenous cows, and the assumed pregnancy loss rate 30 days after conception was significantly higher (P<0.05) in the indigenous cows than in the crossbred cows. The supplemented crossbred cows had a lower pregnancy loss rate than the supplemented indigenous cows (P<0.05). All the supplemented indigenous cows that lost pregnancies were in their first parity, whereas all the crossbred cows that lost pregnancies were multiparous and were not supplemented. The indigenous cows weighed significantly more (P<0.05) than the crossbred cows irrespective of diet, and the supplemented cows of both breeds weighed more (P<0.05) than the control cows. The supplemented indigenous cows had significantly higher (P<0.05) body condition scores than the control cows. The mean dairy milk yield of all the breeds was generally low but significantly higher (P<0.05) in the crossbred than in the indigenous cows.  相似文献   

6.
在奶牛养殖业中,难产是奶牛临床上的常发病,助产是处理难产的常用手段。助产的发生会导致母牛受胎率降低、冻精使用量增加、空怀时间增加和首次配种时间后移等繁殖问题。本研究从细菌学角度分析助产对奶牛产后子宫菌群的影响,以期为提高牧场受胎率提供数据参考。在宁夏地区某大型奶牛场,以助产和非助产奶牛为研究对象,在产后45 d进行子宫灌洗,采集灌洗液样本共7份。通过细菌分离培养、16S rRNA测序等方法分离细菌。结果共分离出10个细菌属,12种细菌,其中,非助产奶牛子宫冲洗液中分离出链霉菌属、链球菌属、肠杆菌属、葡萄球菌属、气球菌属5个属的细菌;助产奶牛子宫冲洗液分离出志贺菌属、不动杆菌属、假单胞菌属、棒状杆菌属、芽胞杆菌属、气球菌属、肠杆菌属、葡萄球菌属、链球菌属等9个属的细菌。本研究的结果表明,助产和非助产奶牛子宫菌群差异显著,助产导致子宫内菌群多样性增加。  相似文献   

7.
AIM: To describe the gross pathology, bacteriology and histopathology of the reproductive tracts of dairy cows that failed to conceive or maintain pregnancy. METHODS: The reproductive tracts of 105 cows that were not pregnant at the end of the seasonal breeding programme were retrieved following slaughter. The tracts were examined grossly, both horns of the uterine lumen were swabbed for bacteriology, and tissue was collected from each horn and the body of the uterus for histopathology. Grossly enlarged uteri and tracts containing purulent vaginal content were excluded. Histopathology was performed on three sections of uterine tissue from each of three cows in which no gross pathological changes were detected and from which no bacteria were isolated, from three cows in which no gross pathology was detected but from which bacteria were isolated, and from three cows in which gross pathological changes were detected but from which no bacteria were isolated. RESULTS: Thirty-six (34%) cows had one or more gross lesions which involved the ovary, uterine tube, uterus or vagina. Bacteria were isolated from the uteri of 22 (21%) cows. Isolates included Arcanobacterium pyogenes (n = 1), Escherichia coli (n = 1), Fusobacterium spp (n = 1), Haemophilus somnus (n = 5), Streptococcus acidominimus (n = 12), S. bovis (n = 2), S. uberis (n = 1) and S. salivarious (n = 1). In only five cows were both gross pathology and bacteria detected. There was no relationship between the isolation of bacteria and the diagnosis of gross pathology of the uterus. There were no differences in the degree of histopathological changes in the uteri from the three groups of cows examined, and lesions present were minor. CONCLUSIONS: Gross pathological changes and intra-uterine bacteria were found in 34% and 20% of cows, respectively, but the correlation between the two was poor. Histopathological changes were unremarkable, suggesting the bacteriological findings were coincidental, that causative agents of infertility were not present at the time of examination, or that unrelated causes such as nutritional anoestrus may have been responsible for the failure of some cows to conceive.  相似文献   

8.
Intrauterine swabs were obtained from cows after calving on two commercial dairy herds with contrasting hygienic environments and incidence of leucorrhea, and cultured aerobically and anaerobically. Of 26 cows with a normal calving and puerperium, eight of 14 (57 per cent) were sterile on farm B where hygiene was poor, compared with five of 12 (42 per cent) on farm A where hygiene was better. Two cows on farm B retained their placentas and subsequently developed metritis/endometritis. Actinomyces pyogenes was the commonest bacterial isolate and Fusobacterium nucleatum, Proteus mirabilis and Bacteroides melaninogenicus were also frequently observed. Similar isolates were obtained from cows on farm B with parturient or puerperal disorders. The contrasting hygienic environments had no influence on either the quantitative or qualitative uterine bacterial flora. Thus, the difference in the incidence of endometritis must have been due to factors other than hygiene.  相似文献   

9.

The effects of high thermal stress on serum protein metabolites, milk production of transition dairy cows in semi-arid areas in South Africa were evaluated. Forty, ±?8 months pregnant, Jersey heifers (±?26 months) in zero grazing management were selected during summer from two semi-arid communal areas. Summer thermal-humidity index (THI) of the areas were THI-1 (72–83: extreme caution) and THI-2 (75–87: danger). Blood samples were collected (21 days pre-partum, and 21 and 75 days post-partum) and analysed for serum protein metabolites. Milk yield was recorded daily and samples collected for milk fat, protein, lactose and urea nitrogen analysis. Heifers in THI-2 had lower (P?<?0.05) total serum proteins, albumin and blood urea nitrogen than THI-1. Post-calving, cows in THI-1 had higher (P?<?0.05) TP (73.4 vs 67.9 g/l) and BUN (4.61 vs 3.77 mmol/l) at 21 DIM, and lower (P creatinine at 21 and 75 DIM than THI-2 group. Milk yield, fat and protein in THI-2 were all lower (P?<?0.05) than THI-1 21DIM. The results confirm that heat stress affects utilisation of nutrients in transition dairy cows.

  相似文献   

10.
In dairy cattle, uterine infections are not life threatening and often unavoidable; however, they reduce fertility and increase the production costs of properties. The aim of this study was to evaluate the incidence of subclinical endometritis from 32 to 70 days in milk (DIM) and its effects on the reproductive performance of crossbred dairy cows. Lactating cows (Holstein/Gir; n?=?172), with no history of retained placenta, without clinical signs of uterine infection were used. The body condition score (BCS) was evaluated on a scale from 1 to 5. Ultrasound examination was performed to evaluate uterine lining and ovarian activity, while vaginal mucus was analyzed by gloved hand. The diagnosis of subclinical endometritis was performed by endometrial cytobrush technique. The samples were collected, stained, and examined microscopically; positive cases for subclinical endometritis were considered with the presence of ≥5 % of neutrophils. Later, the cows were submitted to conventional artificial insemination or timed artificial insemination. The incidence of subclinical endometritis in the herd was 26 %, and this was not affected by the season of calving, presence of corpus luteum, DIM, and parity. Cows with a BCS ≤2.50 had a higher incidence of subclinical endometritis. The conception rate to first insemination and pregnancy rate at 150 days postpartum were not influenced by the presence of subclinical endometritis in crossbred dairy cows.  相似文献   

11.
Repeated ultrasonographic examinations and collections of blood samples and uterine lumenal swabs between seven and 28 days after calving were used to examine the relative effects of bacterial contamination and involution of the uterus on the concentrations of acute phase proteins in the blood of 26 dairy cows. The severity of bacterial contamination, as determined by the total bacterial growth score, was a significant variable for the concentrations of the acute phase proteins alpha1-acid glycoprotein (P < 0.0001), haptoglobin (P < 0.05) and ceruloplasmin (P < 0.0001). In addition, the concentrations of alpha1-acid glycoprotein and ceruloplasmin were increased in the cows from which Escherichia coli (P < 0.0001) and Arcanobacterium pyogenes (P < 0.05), respectively, were isolated from the uterine lumen. Uterine involution, as determined by the decreasing diameter of the previously gravid uterine horn, was associated with a decrease in the concentrations of alpha1-acid glycoprotein (P < 0.005), haptoglobin (P < 0.05) and ceruloplasmin (P < 0.01). However, the response of the acute phase proteins to bacterial contamination was independent of the day on which the samples were collected, indicating that their concentrations were increased by bacterial contamination in addition to the changes associated with uterine involution.  相似文献   

12.
The prevalence and distribution of seropositivity towards the protozoan parasite Neospora caninum were studied in single blood samples from 1561 cows from 31 Danish dairy herds. Blood samples were analysed by an indirect enzyme-linked immunoassay and an indirect fluorescent-antibody test. Seroprevalence in 15 herds with previous abortions assigned to neosporosis ranged from 1% to 58%, with a mean frequency of 22%. In eight out of 16 herds without a history of N. caninum related abortions, no seroreactors were found. In the remaining eight herds, the seroprevalence ranged from 6% to 59%. The prevalence and distribution of seropositivity, gestation number prior to sampling, and breed were related to abortions and perinatal deaths using a random-effects logistic-regression model. Abortion risk was significantly increased in seropositive animals (OR=3) and in 2nd-gestation cows (OR=3). Perinatal death was significantly influenced by gestation number and breed, but not by serostatus. Reproductive performance and culling risk of cows were not affected by serostatus. Seropositivity increased with “age” (i.e. gestation number) (P=0.02). In open cows, seropositivity tended to decrease with distance from calving (P=0.05). The proportion of seropositive pregnant cows increased with trimester (P=0.02).  相似文献   

13.
Early postpartum (6 weeks) ovarian activity, hormonal profiles, uterine involution, uterine infections, serum electrolytes, glucose, milk acetoacetate and blood urea nitrogen (BUN) levels were studied in 2 Estonian high producing dairy herd with annual milk production of 7688 (Farm A) and 9425 (Farm B). From each farm 10 cows, with normal calving performance were used. Blood samples for the hormonal (PGF2alpha-metabolite, progesterone) analyses were withdrawn. On day 25 PP blood serum samples were taken for the evaluation of metabolic/electrolyte status. On the same day estimation of milk acetoacetate values was done. The ultrasound (US) was started on day 7 PP and was performed every 3rd day until the end of experiment. Uterine content, follicular activity and sizes of the largest follicle and corpus luteum were monitored and measured. Vaginal discharge and uterine tone were recorded during the rectal palpation. Each animal in the study was sampled for bacteriological examination using endometrial biopsies once a week. Two types of PGF2alpha-metabolite patterns were detected: elevated levels during 14 days PP, then decline to the basal level and then a second small elevation at the time of final elimination of the bacteria from the uterus: or elevated levels during first 7 days PP, then decline to the basal level and a second small elevation before the final elimination of bacteria. Endometritis was diagnosed in 5 cows in farm A and in 3 cows in farm B respectively. In farm A, 5 cows out of 10 ovulated during experimental period and in 1 cow cystic ovaries were found. In farm B, 3 cows out of 10 ovulated. In 3 cows cystic ovaries were found. Altogether 40% of cows had their first ovulation during the experimental period. Three cows in farm A and 5 cows in farm B were totally bacteria negative during the experimental period. The most frequent bacteria found were A. pyogenes, Streptococcus spp., E. coli., F. necrophorum and Bacteroides spp. The highest incidence of bacteriological species was found during the first 3 weeks in both farms. All animals were free from bacteria after 5th week PP in farm A and after 4th week in farm B respectively. Serum electrolytes and glucose levels were found to be within the reference limits for the cows in both farms. No significant difference was found between farms (p > 0.05). Low phosphorus levels were found in both farms. Significant difference (p < 0.05) was found in BUN levels between farms. In both farms milk acetoacetate values were staying within the reference range given for the used test (< 100 micromol/l). The uterine involution and bacterial elimination in the investigated cows could consider as normal but more profound metabolic studies could be needed to find reasons for later resumption of ovarian activity. Some recommendations to changing feeding regimes and strategies should also be given.  相似文献   

14.
Serum beta-hydroxybutyrate (BHB) levels were determined for 1333 dairy cows in various stages of lactation and parity on 93 dairy farms in Ontario. The data were collected in a cross-sectional manner, as part of the 1992 Ontario Dairy Monitoring and Analysis Program. The median serum BHB was 536 mumol/L for all cows, with a range of 0 to 5801 mumol/L. When subclinical ketosis was defined as a serum BHB level of 1200 mumol/L or higher, the prevalence of ketosis for cows in early lactation (< 65 days in milk (DIM)) was 14.1%. Prevalences for mid lactation (65-149 DIM), late lactation (> 149 DIM), and dry cows were 5.3%, 3.2%, and 1.6%, respectively. The mean serum BHB was significantly higher in the early group compared with each of the other 3 groups (P < 0.05). There was a trend of increasing prevalence with increasing parity across all stages of lactation. Only the difference between the parity-1 group and the parity-4 and greater group was statistically significant (P < 0.05). Both test-day fat percent and test-day protein percent were significantly associated with subclinical ketosis. However, test-day fat percent and test-day protein percent, used alone or in combination, were not useful screening tests for identifying cows with subclinical ketosis.  相似文献   

15.
The objectives of this study were to quantify the effect of 16 ppm of dietary monensin on milk production and composition of dairy cows, and to investigate factors having a potential impact on this effect. Data were generated from a total of 3577 Holstein dairy cows (47 herds) in Quebec enrolled in a herd-level, randomized clinical trial investigating the effects of monensin supplementation. Milk production and composition data were collected from monthly dairy herd improvement (DHI) testing. Monensin increased milk production by 0.9 kg/cow/d in cows under 150 days in milk (DIM) (P < 0.05). Monensin decreased milk fat percentage by 0.18 percentage points during the whole lactation (P < 0.05). This decreasing effect was larger for component-fed cows (P < 0.05) and for cows being fed low levels of dietary physically effective particles (P < 0.05) when compared respectively to cows fed total mixed ration and cows fed high levels of dietary physically effective particles. The results of this study suggest that monensin influences milk production and milk composition of dairy cows, and that diet composition and feeding system influence those effects.  相似文献   

16.
In more than 10 Spanish dairy cows, a bovine herpesvirus 4 (BHV4) associated postpartum metritis was confirmed by virus isolation, BHV4-glycoprotein B (gB) PCR and/or serology. In this study, 12 cows with, and, at the time of sampling, 3 cows without clinical signs of acute postpartum metritis from one large dairy herd in Spain were examined for bacterial and viral infections. Blood, placenta/caruncles and uterine contents were collected between day 1 and day 20 post-calving, and examined for the presence of bacteria and for viruses by virus isolation, BHV4 DNA by BHV4-gB PCR and/or BHV4 antibody titres. Bovine herpesvirus 4 was detected in 83% of the cases with clinical signs of acute postpartum metritis by virus isolation and/or BHV4-gB PCR. An increase of BHV4 antibodies was detected in all examined postpartum metritis cows and in the 3 cows without clinical metritis. Two of these 3 cows developed severe metritis a few dayss after collecting the first blood sample. A concurrent infections of BHV4 and bacteria, mainly Arcanobacterium pyogenes and Streptococcus sp., were detected in 73% of the examined uterine contents collected from postpartum metritis affected cows. This case-report study showed a clear association between BHV4 infections and acute postpartum metritis in dairy cows. In addition, the BHV4-associated postpartum metritis appeared to be an emerging syndrome in this Spanish herd.  相似文献   

17.
OBJECTIVE: To estimate prevalence of Salmonella spp in Ohio dairy farms and to identify potential risk factors for fecal shedding of salmonellae. DESIGN: Cross-sectional study. SAMPLE POPULATION: 105 Ohio dairy farms. PROCEDURE: Individual fecal samples from all mature cows in study herds were tested for Salmonella spp by use of standard bacteriologic culture procedures. Herds were identified as infected if at least 1 cow was shedding Salmonella spp. Information regarding herd characteristics, management practices, and health history were collected. Potential risk factors for herd-level Salmonella infection were identified. RESULTS: In 31% of the study herds (95% confidence interval, 22 to 40%), at least 1 cow was shedding Salmonella spp. Six percent of 7,776 fecal samples contained Salmonella organisms; prevalence within infected herds ranged from < 1 to 97%. Herd size, use of free stalls for lactating and nonlactating cows, and use of straw bedding in nonlactating cows were significantly associated with fecal shedding of Salmonella spp, as determined by use of univariate analysis. By use of multivariate analysis, large herds were more likely to be infected than smaller herds; however, no other factors were associated with Salmonella infection after adjustment for herd size. CONCLUSIONS AND CLINICAL RELEVANCE: Subclinical shedding of Salmonella spp is common in Ohio dairy herds, although we could not identify specific interventions that may influence the prevalence of Salmonella spp on dairy farms. It appears that large herd size and intensive management may provide an environment conducive to Salmonella shedding and chronic dairy herd infection.  相似文献   

18.
Subacute ruminal acidosis(SARA)represents one of the most important digestive disorders in intensive dairy farms,and dairy cows are individually different in the severity of SARA risk.The objectives of the current study were to investigate differences in the ruminal bacterial community and metabolome in dairy cattle with different susceptibility to SARA.In the present study,12 cows were initially enrolled in the experiment.Based on average ruminal pH,4 cows with the lowest ruminal pH were assigned to the susceptible group(SUS,pH=5.76,n=4)and 4 cows with the highest ruminal pH assigned to the tolerant group(TOL,pH=6.10,n=4).Rumen contents from susceptible(SUS,n=4)and tolerant(TOL,n=4)dairy cows were collected through rumen fistula to systematically reveal the rumen microbial and metabolic alterations of dairy cows with different susceptibility to SARA using multi-omics approaches(16S and 18S rRNA gene sequencing and metabolome).The results showed that despite being fed the same diet,SUS cows had lower ruminal pH and higher concentrations of total volatile fatty acids(VFA)and propionate than TOL cows(P<0.05).No significant differences were observed in dry matter intake,milk yield,and other milk compositions between the SUS and TOL groups(P>0.05).The principal coordinates analysis based on the analysis of molecular variance indicated a significant difference in bacterial composition between the two groups(P=0.01).More specifically,the relative abundance of starch-degrading bacteria(Prevotella spp.)was greater(P<0.05),while the proportion of fiber-degrading bacteria(unclassified Ruminococcaceae spp.,Ruminococcus spp.,Papillibacter,and unclassified Family_-XIII)was lower in the rumen of SUS cows compared with TOL cows(P<0.05).Community analysis of protozoa showed that there were no significant differences in the diversity,richness,and community structure(P>0.05).Metabolomics analysis revealed that the concentrations of organic acids(such as lactic acid),biogenic amines(such as histamine),and bacterial degradation products(such as hypoxanthine)were significantly higher in the SUS group compared to the TOL group(P<0.05).These findings revealed that the higher proportion of starch-degrading bacteria/lower fiber-degrading bacteria in the rumen of SUS cows resulted in higher VFA-producing capacity,in particular propionate.This caused a disruption in metabolic homeostasis in the rumen which might be the reason for the higher susceptibility to SARA.Overall,these findings enhanced our understanding of the ruminal microbiome and metabolic changes in cows susceptible to SARA.  相似文献   

19.
The objectives of the study were to characterize an ultrasound reproductive tract scoring (URTS) system to assess suitability for breeding in dairy cows, to describe the prevalence of these scores in commercial dairy herds and to examine their relationship with subsequent fertility. Ultrasound examinations (7797) were performed on 5751 Holstein–Friesian cows prior to breeding in 62 seasonally calving herds over 2 years. Data recorded from images of both ovaries and the uterus were combined into a six point scoring system and the prevalence of cows with cystic ovarian follicles and uterine abscesses and adhesions was recorded separately. The prevalence of ovulatory cows which had completed uterine involution (score 1), or had mild (2) or moderate endometritis (3) was 62.5%, 21.7% and 2.2%, respectively. The prevalence of anovulatory cows with moderate endometritis (4), ovulatory cows with pyometra (5) and anovulatory cows which had completed uterine involution (6) was 3.3%, 2.2% and 8.1%, respectively. The interval between calving and examination differed between cows with each of the scores 1, 2, 5 and 6 (61, 46, 53 and 50 days, respectively, p < 0.05) but not between cows with scores 3 and 4 (37 and 35 days, respectively). Ovulatory cows which had completed uterine involution (score 1) had a higher likelihood of pregnancy to first service than ovulatory or anovulatory cows which had not completed uterine involution (p ≤ 0.10). The prevalence of cows with cystic ovarian follicles or abscesses or adhesions of the reproductive tract was 3.9% and 1.2%, respectively. In conclusion, 29% and 11% of cows in seasonally calving and breeding dairy herds had not completed uterine involution or were anovulatory prior to the mating start date, respectively. Both conditions, detected using a URTS system, significantly reduced first service pregnancy rate in these pasture-based dairy herds.  相似文献   

20.
OBJECTIVE: To determine the prevalence of Salmonella spp in the cecal-colon contents of cull (market) dairy cows at slaughter because of potential public health ramifications. DESIGN: Survey study. SAMPLE POPULATION: Cecal-colon contents collected from 5,087 cull (market) dairy cows at slaughter at 5 slaughter establishments across the United States. PROCEDURE: During 2 periods of the year, winter (January and February) and summer (July through September), 5 cull (market) cow slaughter establishments in the United States--west (WE), southeast (SEE), central (CE), north central (NCE), and south central (SCE)--establishments were visited, and cecal-colon contents of cull dairy cows were obtained at the time of slaughter. Samples were examined by microbiologic culture at a single laboratory for Salmonella spp. RESULTS: Salmonella spp were detected in 23.1% of cecal-colon content samples from cull dairy cows across the 5 slaughter establishments. The highest site prevalence (54.5%) was detected at the WE during the summer period, whereas the lowest was found at the CE during the summer (4.3%) and at the NCE during the winter (4.5%). Considerable variation in the daily prevalence of Salmonella spp was found, particularly at the WE and the SCE. Salmonella spp were isolated from 93% of cecal-colon contents collected on a summer day at the WE. CONCLUSIONS AND CLINICAL RELEVANCE: Results strongly suggest that there is a high prevalence of Salmonella spp in cull dairy cows at slaughter, which could burden Hazard Analysis Critical Control Point programs implemented in slaughter establishments. Procedures to reduce Salmonella load at the dairy farm and during transport to slaughter could reduce the risk of spread during the slaughter process.  相似文献   

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