Characterization and identification of microbial communities in bovine necrotic vulvovaginitis.

Bovine necrotic vulvovaginitis (BNVV) is a severe and potentially fatal disease of post-partum cows that emerged in Israel after large dairy herds were merged. While post-partum cows are commonly affected by mild vulvovaginitis (BVV), in BNVV these benign mucosal abrasions develop into progressive deep necrotic lesions leading to sepsis and death if untreated. The etiology of BNVV is still unknown and a single pathogenic agent has not been found. We hypothesized that BNVV is a polymicrobial disease where the normally benign vaginal microbiome is remodeled and affects the local immune response. To this end, we compared the histopathological changes and the microbial communities using 16S rDNA metagenetic technique in biopsies taken from vaginal lesions in post-partum cows affected by BVV and BNVV. The hallmark of BNVV was the formation of complex polymicrobial communities in the submucosal fascia and abrogation of neutrophil recruitment in these lesions. Additionally, there was a marked difference in the composition of bacterial communities in the BNVV lesions in comparison to the benign BVV lesions. This difference was characterized by the abundance of Bacteroidetes and lower total community membership in BNVV. Indicator taxa for BNVV were Parvimonas, Porphyromonas, unclassified Veillonellaceae, Mycoplasma and Bacteroidetes, whereas unclassified Clostridiales was an indicator for BVV. The results support a polymicrobial etiology for BNVV.

The effects of bovine necrotic vulvo-vaginitis on reproductive and production performance of Israeli 1st calf heifers.

Bovine necrotic vulvovaginitis (BNVV) is a syndrome unique to Israel characterized by necrotic lesion in the caudal vagina mainly in first calf heifers after calving, associated with Porphyromonas levii. The objectives of this study were to analyze the impact of BNVV on reproductive performance, milk production and survival in the heard of first calf dairy heifers in affected farms, and to verify if the effects of BNVV are severity-dependent. For assessment of the severity level a scale of 4 degrees was formed, and cows were scored 4 to 6 d after calving. Data were obtained from two dairy farms during 2006-07, consisting of 603 lactations. The incidence and the severity of BNVV declined between 2006 and 2007, and severe BNVV tended to be more prevalent in the summer. The odds to conceive in the first artificial insemination of BNVV cow tended to be lower than healthy cows (OR = 0.676, P = 0.052). Cows with BNVV had longer empty period (145.8 d vs. 135.1 d of healthy cows, P = 0.031), but only severe BNVV had a negative effect on the odds of the cow to be empty at 150 d in milk (DIM) (OR = 2.05, P = 0.052). Severe BNVV also affected the mean survival time to conception (155.9 d vs. 142.3 d, P = 0.042). All BNVV severity degrees had a negative effect on milk production. The effect on milk production was not limited only to the beginning of the lactation, cows with BNVV produced 338.1 kg milk less than healthy cows (P = 0.016) in 305 d corrected lactation. The effect on milk production was not severity depended. No effect on survival time in the herd was demonstrated.

Exposure to endotoxin during estrus alters the timing of ovulation and hormonal concentrations in cows.

The effect of intramammary (IMM) or intravenous (IV) administration of E. coli endotoxin (LPS), at the onset of estrus, at the time of ovulation was examined. Steroid and gonadotropin concentrations around ovulation were also determined. Lactating Holstein cows (n=33) were assigned to saline-controls (n=12) and treated with LPS-IV (0.5 microg/kg; n=13) or LPS-IMM (10 microg; n=8). Synchronized cows were observed continuously for estrus. LPS (or saline) was injected within 30 min from the onset of standing estrus, at peak estradiol concentrations. The typical rise of body temperature, somatic cell count, cortisol, and NAGase activity was noted. One-third of both LPS-IV- and LPS-IMM-treated cows were manifested by an extended estrus to ovulation (E-O) interval of around 75 h or did not ovulate, compared with about 30 h in the other 2/3 of LPS cows and all controls. Estradiol concentrations 24 h before and after LPS did not differ between groups. However, LPS-IV cows with extended intervals exhibited another estrus and an additional rise of estradiol followed by delayed ovulation. LPS-treated cows with a delayed E-O interval had low or delayed LH surge; two LPS-treated cows did not exhibit LH surge and did not ovulate. All control cows exhibited normal hormone levels. Delayed ovulation was associated with a delayed rise of luteal progesterone. The results indicated that exposing cows to endotoxin during estrus induced a decreased and delayed LH surge in one-third of the cows. This was associated with delayed ovulation, which reduces the chances of successful fertilization.

Effects of bovine necrotic vulvovaginitis on productivity in a dairy herd in Israel.

Bovine necrotic vulvovaginitis (BNVV) is characterized by the development of a necrotic vulvovaginal lesion, almost exclusively in post-parturient first-lactation cows, associated with Porphyromonas levii. The scope of this survey was to evaluate the impact of BNVV on herd productivity as a means to rationally evaluate the resources that should be allocated in dealing with the syndrome. During an outbreak of BNVV in a dairy herd, following the introduction of a large number of cows from another farm, the impact of the animals' origin (local or transferred) and BNVV (positive or negative) upon involuntary culling rate, milk yield and days between pregnancies were assessed. The results indicated that the number of days between pregnancies was significantly higher in first-lactation cows with BNVV but was not influenced by the other independent variables. None of the other variables included in this survey had any effect on the involuntary culling rate and milk yield.

Sample-based assessment of the microbial etiology of bovine necrotic vulvovaginitis.

A semiquantitative evaluation of potential bacterial pathogens was correlated to the severity of lesions during an outbreak of bovine necrotic vulvovaginitis (BNVV) on an Israeli dairy herd. Bacteriologic examination of 287 vaginal swabs from 104 post-calving heifers showed a highly significant correlation between Porphyromonas levii colony forming unit numbers and the clinical scores of the lesions, when assessed by an ordinal regression statistical model. No such correlation was found for the other bacteria included in the study. Nineteen samples taken for virological examinations resulted negative for bovine herpes viruses 1, 2, 4 and 5. Thus the results of this study substantiate the essential role of P. levii in the etiology of BNVV and indicate that BHV4 is not required as a predisposing factor to the syndrome.

A herd level analysis of urinary tract infection in dairy cattle.

Cystitis, urethritis and pyelonephritis in cattle most commonly result from ascending urinary tract infection with Corynebacterium renale, Corynebacterium cystidis, Corynebacterium pilosum or Escherichia coli. We describe the clinical, bacteriological, clinical-pathological and epidemiological findings in a dairy cattle herd with urinary tract infection (UTI). Blood and urine samples from 17 calves and 19 cows were submitted to laboratory examinations. Depression, muscle wasting, weakness and frequent urine dribbling were the main characteristics of UTI in calves. Affected cows showed weight loss and an abrupt reduction in feed intake and milk production. Enlargement of the left kidney and loss of normal lobulation were evident on rectal examination. E. coli was the most frequent cause of UTI but C. renale, alpha-haemolytic Streptococcus spp., Proteus spp. Pseudomonas aeruginosa, Klebsiella spp. and Oligella urethralis were isolated as well. Differences in total protein and several protein fractions were found between affected and healthy animals.

Four-year survey of urinary tract infections in calves in Israel.

The prevalence of urinary tract infections in calves aged seven days to three months in three dairy cattle herds ranged from 0.5 to 1.6 per cent, with an average of 1.1 per cent. The mortality rate reached 16.1 per cent. The morbidity rate of the female calves was 1.4 per cent and that of the male calves 0.8 per cent. The bacteria isolated from urine, and from vaginal and preputial swabs were Escherichia coli (35 per cent), Corynebacterium renale (14 per cent), plasma coagulase-negative Staphylococcus species (12 per cent), Pseudomonas aeruginosa (12 per cent), Proteus species (12 per cent) and Arcanobacterium pyogenes (5 per cent). The affected calves had a significantly lower serum concentration of inorganic phosphorus (P < 0.01).