Search

Background: Emergence and spread of antibiotic resistance has become a global health threat and is often linked with overuse and misuse of clinical and veterinary chemotherapeutic agents. Modern industrial-scale animal feeding operations rely extensively on veterinary pharmaceuticals, including antibiotics, to augment animal growth. Following excretion, antibiotics are transported through the environment via runoff, leaching, and land application of manure; however, airborne transport from feed yards has not been characterized. Objectives: The goal of this study was to determine the extent to which antibiotics, antibiotic resistance genes (ARG), and ruminant-associated microbes are aerially dispersed via particulate matter (PM) derived from large-scale beef cattle feed yards. Methods: PM was collected downwind and upwind of 10 beef cattle feed yards. After extraction from PM, five veterinary antibiotics were quantified via high-performance liquid chromatography with tandem mass spectrometry, ARG were quantified via targeted quantitative polymerase chain reaction, and microbial community diversity was analyzed via 16S rRNA amplification and sequencing. Results: Airborne PM derived from feed yards facilitated dispersal of several veterinary antibiotics, as well as microbial communities containing ARG. Concentrations of several antibiotics in airborne PM immediately downwind of feed yards ranged from 0.5 to 4.6 μg/g of PM. Microbial communities of PM collected downwind of feed yards were enriched with ruminant-associated taxa and were distinct when compared to upwind PM assemblages. Furthermore, genes encoding resistance to tetracycline antibiotics were significantly more abundant in PM collected downwind of feed yards as compared to upwind. Conclusions: Wind-dispersed PM from feed yards harbors antibiotics, bacteria, and ARGs. Citation: McEachran AD, Blackwell BR, Hanson JD, Wooten KJ, Mayer GD, Cox SB, Smith PN. 2015. Antibiotics, bacteria, and antibiotic resistance genes: aerial transport from cattle feed yards via particulate matter. Environ Health Perspect 123:337-343; http://dx.doi. org/10.1289/ehp.1408555 [ABSTRACT FROM AUTHOR]

Mycobacterium (M.) bovis, a bacterium in the M. tuberculosis complex, is a causative agent of bovine tuberculosis, a contagious disease of animals. Mycobacterial culture is the gold standard for diagnosing bovine tuberculosis, but this technique is laborious and time-consuming. In the present study, performance of the SD Bioline TB Ag MPT4 Rapid test, an immunochromatographic assay, was evaluated using reference bacterial strains and M. bovis field isolates collected from animals. The SD MPT64 Rapid test produced positive results for 95.5% (63/66) of the M. bovis isolates from cattle and 97.9% (46/47) of the isolates from deer. Additionally, the test had a sensitivity of 96.5% (95% CI, 91.2-99.0), specificity of 100% (95% CI, 96.7-100.0), positive predictive value of 100% (95% CI, 96.7-100.0), and negative predictive value of 92.9% (95% CI, 82.7-98.0) for M. bovis isolates. In conclusion, the SD MPT64 Rapid test is simple to use and may be useful for quickly confirming the presence of M. bovis in animals. [ABSTRACT FROM AUTHOR]

The main pathogenic enterohemorrhagic Escherichia coli (EHEC) strains are defined as Shiga toxin (Stx)-producing E. coli (STEC) belonging to one of the following serotypes: O157:H7, O26:H11, O103:H2, O111:H8, and O145:H28. Each of these five serotypes is known to be associated with a specific subtype of the intimin-encoding gene (eae). The objective of this study was to evaluate the prevalence of bovine carriers of these "top five" STEC in the four adult cattle categories slaughtered in France. Fecal samples were collected from 1,318 cattle, including 291 young dairy bulls, 296 young beef bulls, 337 dairy cows, and 394 beef cows. A total of 96 E. coli isolates, including 33 top five STEC and 63 atypical enteropathogenic E. coli (aEPEC) isolates, with the same genetic characteristics as the top five STEC strains except that they lacked an stx gene, were recovered from these samples. O157:H7 was the most frequently isolated STEC serotype. The prevalence of top five STEC (all serotypes included) was 4.5% in young dairy bulls, 2.4% in young beef bulls, 1.8% in dairy cows, and 1.0% in beef cows. It was significantly higher in young dairy bulls (P<0.05) than in the other 3 categories. The basis for these differences between categories remains to be elucidated. Moreover, simultaneous carriage of STEC O26:H11 and STEC O103:H2 was detected in one young dairy bull. Lastly, the prevalence of bovine carriers of the top five STEC, evaluated through a weighted arithmetic mean of the prevalence by categories, was estimated to 1.8% in slaughtered adult cattle in France. [ABSTRACT FROM AUTHOR]

Bovine tuberculosis is a chronic, infectious, and contagious zoonotic disease of domestic animals, wild animals, and humans. It also poses a public health threat and economic losses. This study was aimed at determining the prevalence of bovine tuberculosis in slaughtered cattle, based on PM meat inspection, Ziehl-Neelsen staining, and PCR techniques in Bauchi State, Nigeria. A Prospective study was conducted on 800 cattle slaughtered in the three Zonal abattoirs of Bauchi State, Nigeria. One hundred and twenty (15%) tissues from different organs had suspected bTB lesions at PM. Out of the samples examined 35 (29.2%) were AFB positive by ZN and 10 (8.3%) were confirmed positive for M. bovis by PCR, with an overall prevalence of 29.16% and 8.33%, respectively. Female had a higher prevalence rate than male cattle at 16.66% and 12.5 % by ZN and 5.00% and 3.33% by PCR, respectively (P > 0.05, χ2 = 0.218). However, there was a statistically significant association (P < 0.05, χ2 = 7.002) between detection of bTB and the age of cattle. ZN revealed that cattle aged 6 years and above had the highest number of positive bTB cases 67.9%, while cattle aged 3-5 years had the lowest 14.81%. PCR technique revealed that the cattle aged 6 and above years also had the highest percentage positive M. bovis cases of 22.84%, whereas cattle aged 3-5 years had the lowest and the overall prevalence rate of 8.33%. The study found a high infection rate of bTB among cattle and majority of the lesions 54.2% were from lungs. The prevalence of bTB was higher in Bauchi metropolitan abattoir which supplies larger population of the state with beef. [ABSTRACT FROM AUTHOR]

This study was carried out to investigate the prevalence of Babesia bovis and B. bigemina in cattle in Erzurum region by Real Time PCR and to characterize the isolates molecularly. Totally 300 whole blood samples from clinically healthy cattle in different ages, sex and breeds were collected into the tubes with EDTA in 2011-2012. Following DNA extraction, Sybergreen and TaqMan probe based Real Time PCR analyses were carried out with B. bovis and B. bigemina primers amplifying msa-2c and rap-1 gene regions. Out of 300 samples, 28 (9.3%) and 17 (5.7%) were found to be infected with B.bovis and B. bigemina. No mix infection was found in the samples. Four of B. bovis and three of B. bigemina isolates were sequenced with respect to msa-2c and rap-1 gene regions for phylogenetic analyses. According to pairwise comparisons of B. bovis isolates, genetic distances were found as 0.6%, 2.3%, and 7.5%, among each other, some other isolates in Turkey, and in the world, respectively. In the phylogenetic analyses of B.bigemina, genetic differences were detected as 0.3% and 0.5% among each other and the other isolates in the world. In the statistical analyses of B. bovis and B. bigemina positive samples according to age, sex and breed of cattle no statistical significance (p>0.05) was founded according to age and breed while the statistical difference according to sex was found significant for B. bigemina (p<0.05), and not significant for B. bovis (p>0.05). In conclusion, the molecular characterization and the prevalence of B. bovis and B. bigemina in cattle in Erzurum region were determined by Real Time PCR. This is the first report on the molecular characterizations of B. bovis and B. bigemina in Erzurum region. [ABSTRACT FROM AUTHOR]

In vitro phagocytosis and apoptosis activity was evaluated in polymorphonuclear leukocytes (PMN) dairy cattle in the presence of Staphylococcus aureus capsular types 5 and 8. PMN were obtained from clinically healthy cows. The phagocytic activity of neutrophils was assayed through the phagocytic capacity and phagocytic index. Apoptosis was determined by light microscopy (LM) and epifluorescence (FM). Differences were observed between treatments in LM regarding the capacity of phagocytosis; compact type (CC) were 86.50±2.93, capsular serotype 5 (CP5) 74.98±2.44 and capsular serotype 8 (CP8) 82.22±1.50 (P<0.05). The values for the phagocytic index were: CC 6.13±0.31, CP5 4.88±0.13 and CP8 5.22±0.10 (P<0.05). The phagocytic capacity in the FM was: CC 86.77±2.6, CP5 62.52±3.26 and CP8 78.60±4.07. The phagocytic index for CC was 7.62±0.55, CP5 4.67±0.29 and CP8 5.53±0.40 (P<0.05). The percentages of apoptosis evaluated by LM were: positive control (C+) 97.7±1.28, negative control (C-) 27.13±1.85, CC 35.44±2.56 CP5 60.07±4.21, CP8 45.57±4.34 and CP5 52.78±3.29. In the FM technique were: C(+) 95.61±2.66, C(-) 20.2±1.77, CC 26.5±1.65, CP8 41.33±2.32 respectively (P<0.05). Differences in the in vitro phagocytosis capacity, phagocytic index and apoptosis of PMN were found between the S. aureus serotypes tested. Type CP5 decreased phagocytic activity and significantly increased the apoptosis compared with type CP8 in PMN. [ABSTRACT FROM AUTHOR]

Serogroup O80 was detected in 40% of 104 enteropathogenic Escherichia coli isolates from calves with diarrhea from 42 farms in Belgium during 2008‒2015. These isolates harbored the eae-ξ and fliCH2 genes, similar to the O80 attaching-effacing Shigatoxigenic E. coli isolates found in humans in France. This strain might be emerging. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing Escherichia coli O157:H7 primarily resides in cattle asymptomatically, and can be transmitted to humans through food. A study by Lupolova et al. applied a machine-learning approach to complex pan-genome information and predicted that only a small subset of bovine isolates have the potential to cause diseases in humans. [ABSTRACT FROM AUTHOR]

Besnoitia besnoiti and Besnoitia tarandi are two cyst-forming apicomplexan parasites of the genus Besnoitia . B. besnoiti uses cattle as an intermediate host, in which it causes a disease that progresses in two sequential phases: the acute anasarca stage and the chronic scleroderma stage. Reindeer and caribou act as intermediate hosts for B. tarandi , which causes clinical signs similar to those caused by B. besnoiti . Previous studies demonstrated high molecular similarity, as determined by 18S and ITS-1 RNA sequences, between these Besnoitia spp., and strong serological cross-reactivity between these species has recently been demonstrated. Thus, a difference gel electrophoresis approach and mass spectrometry analysis were used to describe the proteomes and explore differences in protein abundance between B. besnoiti and B. tarandi in tachyzoite extracts. Immunoproteomes were also compared using 2-DE immunoblotting with polyclonal sera from experimentally infected rabbits. From approximately 1400 spots detected in DIGE-gels, 28 and 29 spots were differentially abundant in B. besnoiti and B. tarandi tachyzoites, respectively (±1.5-fold, p < 0.05). Four and 13 spots were exclusively detected in B. besnoiti and B. tarandi , respectively. Of the 32 differentially abundant spots analyzed by MALDI-TOF/MS, 6 up-regulated B. besnoiti proteins (LDH; HSP90; purine nucleoside phosphorylase and 3 hypothetical proteins) and 6 up-regulated B. tarandi proteins (G3PDH; LDH; PDI; mRNA decapping protein and 2 hypothetical proteins) were identified. Interestingly, no specific antigen spots were recognized by sera on any of the Besnoitia species studied and a similar antigen profile has been observed for B. tarandi and B. besnoiti sera when cross reactions were studied. This fact corroborates the difficulty in discerning Besnoitia infections using current serological assays. The present study underscores the importance of sequencing the B. besnoiti genome for species diversity studies of the genus Besnoitia . [ABSTRACT FROM AUTHOR]

Onchocerca ochengi is a nodule-forming filarial nematode parasite of cattle in tropical Africa and closely related to the human pathogen Onchocerca volvulus . The adult worms reside in intradermal nodules. While females are sedentary, males may move between nodules. The first stage larvae (microfilariae) disperse in the skin of the host waiting to be taken up by the intermediate host. The density of microfilariae in the skin is largely independent of the number of adult worms present indicating some form of density dependent control. Recently, Onchocerca sp. Siisa, a form of Onchocerca distinguishable from O. ochengi by mitochondrial DNA sequences but not by morphology, was described to occur in cattle. This raised the question if Onchocerca sp. Siisa represents a different mitochondrial clade of O. ochengi or a new species. In order to study the reproductive biology and to understand this self-control of the off-spring population we systematically analyzed all Onchocerca nodules from the skin of one zebu cow and we examined a sample of microfilariae from a skin biopsy. We identified 87 O. ochengi females and 146 males. 56 (64.4%) of the females contained developing embryos. In order to assign the progeny to their respective parents we determined the genotypes at six nuclear and two mitochondrial molecular genetic markers in the adult worms, in a fraction of the progeny present in the uteri of the females and in the skin microfilariae. The 121 skin microfilariae we analyzed originated from at least 17 different mothers, which contributed rather differently to the total. Forty-five larvae (37.2%) were the progeny of a single female. Of the adult worms 16.7% were of the type Onchocerca sp. Siisa. These worms appeared to interbreed freely with the rest of the O. ochengi population and therefore belong to the same species. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate the effect of cashew nut shell extract (CNSE) and glycerol (purity >99%) on enteric methane (CH4) production and microbial communities in an automated gas in vitro system. Microbial communities from the in vitro system were compared with samples from the donor cows, in vivo. Inoculated rumen fluid was mixed with a diet with a 60:40 forage:concentrate ratio and, in total, 5 different treatments were set up: 5 mg of CNSE (CNSE-L), 10 mg of CNSE (CNSE-H), 15 mmol of glycerol/L (glycerol-L), and 30 mmol of glycerol/L (glycerol-H), and a control without feed additive. Gas samples were taken at 2, 4, 8, 24, 32, and 48 h of incubation, and the CH4 concentration was measured. Samples of rumen fluid were taken for volatile fatty acid analysis and for microbial sequence analyses after 8, 24, and 48 h of incubation. In vivo rumen samples from the cows were taken 2 h after the morning feeding at 3 consecutive days to compare the in vitro system with in vivo conditions. The gas data and data from microbial sequence analysis (454 sequencing) were analyzed using a mixed model and principal components analysis. These analyses illustrated that CH4 production was reduced with the CNSE treatment, by 8 and 18%, respectively, for the L and H concentration. Glycerol instead increased CH4 production by 8 and 12%, respectively, for the L and H concentration. The inhibition with CNSE could be due to the observed shift in bacterial population, possibly resulting in decreased production of hydrogen or formate, the methanogenic substrates. Alternatively the response could be explained by a shift in the methanogenic community. In the glycerol treatments, no main differences in bacterial or archaeal population were detected compared with the in vivo control. Thus, the increase in CH4 production may be explained by the increase in substrate in the in vitro system. The reduced CH4 production in vitro with CNSE suggests that CNSE can be a promising inhibitor of CH4 formation in the rumen of dairy cows. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a major mastitis-causing pathogen. Various genotypes have been recently identified in Switzerland but Staph. aureus genotype B (GTB) was the only genotype associated with high within-herd prevalence. The risk of introducing this Staph. aureus genotype into a herd may be increased by frequent animal movements. This may also be the case when cows from different herds of origin are commingled and share their milking equipment for a limited period of time. The aim of the present study was to determine the prevalence of Staph. aureus GTB in seasonally communal dairy herds before and after a summer period when dairy farming is characterized by mixing cows from different herds of origin in 1 communal operation. In addition, the environment was investigated to identify potential Staph. aureus GTB reservoirs relevant for transmission of the disease. A total of 829 cows from 110 herds of origin in 9 communal operations were included in the study. Composite milk samples were collected from all cows during the first or second milking after arrival at the communal operation and again shortly before the end of the season. Swab samples from the environment, involved personnel, and herding dogs present were collected before the cows arrived. At the end of the season, sampling of personnel was repeated. All samples were analyzed for the presence of Staph. aureus GTB using an established quantitative PCR. At the beginning of the season, Staph. aureus GTB-positive cows were identified in 7 out of 9 communal operations and the within-communal operation prevalence ranged from 2.2 to 38.9%. At the second sampling, all communal operations were Staph. aureus GTB positive, showing within-communal operation prevalence from 1 to 72.1%. The between-herd of origin prevalence increased from 27.3 to 56.6% and the cow-level prevalence increased from 11.2% at the beginning of the season to 29.6% at the end of the season. On 3 different communal operations, Staph. aureus GTB-positive swabs from seasonally employed personnel were identified at the end of the season. The results indicate that Staph. aureus GTB can easily spread in communal operations when cows from different herds of origin are mixed during the summer season. Effective management measures need to be designed to prevent the spread of Staph. aureus GTB in seasonally communal herds. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes occurrence was assessed in three slaughterhouses located in Minas Gerais state, Brazil, by analysis of 209 bovine carcasses. Four sponge samples were obtained from each carcass in different steps (A, from hide, before bleeding; B, after hide removal; C, after evisceration; and D, after end washing), resulting in a total of 836 samples. The samples were tested for the presence of L. monocytogenes according to the International Organization for Standardization 11290-1, and positive results were recorded in steps A (1 of 209) and D (1 of 209) from slaughterhouse 03. L. monocytogenes isolates (n = 5) were identified by multiplex PCR as belonging to serogroup He (representing serotypes l/2c or 3c) and presented identical pulsed-field gel electrophoresis profiles; in addition, the isolates harbored the virulence genes inIA, inIB, inIC, inIJ, plcA, hlyA, actA, and iap and were sensitive to ampicillin, vancomycin, gentamicin, erythromycin, tetracycline, rifampin, chloramphenicol, trimethoprim, and sulfamefhoxazole. The obtained data indicated a low occurrence of L. monocytogenes on bovine hides and carcasses from slaughterhouses located in Minas Gerais state, Brazil, and the presence of distinct virulence makers and susceptibility to a variety of antimicrobials by the obtained isolates. [ABSTRACT FROM AUTHOR]

Cattle are the main reservoirs for Shiga toxin-producing Escherichia coli (STEC) strains. E. coli 026, 045, O103, O111, O121, O145, and O157 are among the STEC serogroups that cause severe foodborne illness and have been declared as adulterants by the U.S. Department of Agriculture, Food Safety and Inspection Service. The objectives of this study were (i) to estimate the prevalence of non-O157 STEC and E. coli O157 in naturally infected beef cows and in steer calves at postweaning, during finishing, and at slaughter and (ii) to test non-O157 STEC isolates for the presence of virulence genes stx1, stx2, eaeA, and ehlyA. Samples were collected from study animals during multiple sampling periods and included fecal grabs, rectal swabs, and midline sponge samples. Laboratory culture, PCR, and multiplex PCR were performed to recover and identify E. coli and the virulence genes. The prevalence of non-O157 STEC (serogroups 026, 045, O103, O 111, O 121, O 113, and O 145) fecal shedding ranged from 8% (4 of 48 samples) to 39% (15 of 38 samples) in cows and 2% (1 of 47 samples) to 38% (9 of 24 samples) in steer calves. The prevalence of E. coli O 157 fecal shedding ranged from 0% (0 of 38 samples) to 52% (25 of 48 samples) in cows and 2% (1 of 47 samples) to 31% (15 of 48 samples) in steer calves. In steer calves, the prevalence of non-O157 STEC and E. coli O157 was highest at postweaning, at 16% (15 of 96 samples) and 23% (22 of 96 samples), respectively. Among the 208 non-O157 STEC isolates, 79% (164 isolates) had stxl, 79% (165 isolates) had stx2, and 58% (121 isolates) had both stx1 and stx2 genes. The percentage of non-O157 STEC isolates encoding the eaeA gene was low; of the 165 isolates tested, 8 (5%) were positive for eaeA and 135 (82%) were positive for ehlyA. Findings from this study provide further evidence of non-O157 STEC shedding in beef cows and steer calves particularly at the stage of postweaning and before entry into the feedlot. [ABSTRACT FROM AUTHOR]

A total of 156 Shiga-like toxin producing Escherichia coli (STEC) were isolated from fecal samples of Korean native (100/568, 18%) and Holstein dairy cattle (56/524, 11%) in Korea between September 2010 and July 2011. Fifty-two STEC isolates (33%) harbored both of shiga toxin1 (stx1) and shiga toxin2 (stx2) genes encoding enterohemolysin (EhxA) and autoagglutinating adhesion (Saa) were detected by PCR in 83 (53%) and 65 (42%) isolates, respectively. By serotyping, six STEC from native cattle and four STEC from dairy cattle were identified as 0-serotypes (026, 0111, 0104, and 0157) that can cause human disease. Multilocus sequence typing and pulsed-field gel electrophoresis patterns highlighted the genetic diversity of the STEC strains and difference between strains collected during different years. Antimicrobial susceptibility tests showed that the multidrug resistance rate increased from 12% in 2010 to 42% in 2011. Differences between isolates collected in 2010 and 2011 may have resulted from seasonal variations or large-scale slaughtering in Korea performed to control a foot and mouth disease outbreak that occurred in early 2011. However, continuous epidemiologic studies will be needed to understand mechanisms. More public health efforts are required to minimize STEC infection transmitted via dairy products and the prevalence of these bacteria in dairy cattle. [ABSTRACT FROM AUTHOR]

The article discusses a study aimed to characterize bacterial microbiota present in gallbladder epithelium of cattle and to evaluate the antimicrobial resistance of isolates of genus Staphylococcus. It mentions that the study included an antimicrobial susceptibility testing which showed that strains of Staphylococcus from both gallbladder epithelium and bile are sensitive towards antimicrobials such as cetriaxone. The study found that gallbladder of cattle supports microorganisms.

Copyright of Archivos de Medicina Veterinaria is the property of Universidad Austral de Chile, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In contrast to the well-characterized chemotaxis and migratory behavior between the dorsal and ventral locations of the rumen by isotrichids, we hypothesized that chemotaxis toward soluble nutrients maintains entodiniomorphid protozoa in the particulate fraction. The objectives of these experiments were to compare the dose-responsive chemotaxis (1) toward different glucose concentrations when ruminal samples were harvested from fed versus fasted cows; (2) toward increasing concentrations of glucose compared with xylose when protozoa were harvested from a fed cow; (3) toward peptides of bacterial, protozoal, and soy origin; and (4) toward glucose when mixed ruminal protozoa were previously incubated for 0, 3, or 6 h in the presence of emulsified polyunsaturated fatty acids (PUFA; Liposyn II, Hospira, Lake Forest, IL). In experiment 1, isotrichid protozoa decreased chemotaxis toward increasing glucose concentration when cows were fasted. Entodiniomorphids exhibited chemotaxis to similar concentrations of glucose as did isotrichids, but to a lesser magnitude of response. In experiment 2, xylose was chemotactic to both groups. Xylose might draw fibrolytic entodiniomorphid protozoa toward newly ingested feed. In contrast, even though isotrichids should not use xylose as an energy source, they were highly chemoattracted to xylose. In experiment 3, entodiniomorphids were not selectively chemoattracted toward bacterial or protozoal peptides compared with soy peptides. In experiment 4, despite isotrichid populations decreasing in abundance with increasing time of incubation in PUFA, chemotaxis to glucose remained unchanged. In contrast, entodiniomorphids recovered chemotaxis to glucose with increased time of PUFA incubation. Current results support isotrichid chemotaxis to sugars but also our hypothesis that a more moderate chemotaxis toward glucose and peptides explains how they swim in the fluid but pass from the rumen with the potentially digestible fraction of particulates. [ABSTRACT FROM AUTHOR]

Cattle grazing dormant western range-lands may have a high ruminai acetate to propionate ratio (A:P) and may have low tissue clearance of acetate. Increasing propionate production could shift this ratio and improve animal performance. In Exp. 1, the effect of Propionibacterium acidipropionici PI69 (PA) on forage digestibility and VFA production was evaluated in vitro using 2 substrates: 100% donnant wann-season grass extrusa and 50% sorghum-Sudan hay with 50% ground corn (DM basis). The objective of Exp. 2 was to evaluate the effect of PA or calcium propionate supplementation on digestibility, ruminai fermentation, acetate clearance, and BW change. Twelve 2-yr-old, pregnant Brangus heifers (BW = 416 ± 85 kg) were assigned to 1 of 3 treatments. All cattle were fed a basal ration of Old World Bluestem hay (Bothriochloa ischaemum; 5.8% CP and 76.5% NDF, DM basis) at 1.5% BW from d -10 to d 49. Treatments included a protein supplement (CON; 36% CP and 35% RUP, DM basis; 454 g/ animal fed twice daily), CON plus 6 x 1010 cfu PA/animal (BACT), and CON plus 80 g calcium propionate (PROP). After initiation of treatments (d 0), rumen fluid was collected via oral lavage every 3 d and analyzed for VFA, pH, and ammonia. Glucogenic potential of treatments was evaluated with an acetate tolerance test on d 49. In Exp. 1, PA addition increased IVDMD {P < 0.001 ) and total VFA (P < 0.001) of 100% dormant warm-season grass extrusa but not 50% sorghum-Sudan hay with 50% ground com (P ≥ 0.28). The addition of PA decreased (P < 0.001) acetate, increased propionate (P < 0.001), and decreased A:P ratio {P < 0.001) for both substrates. In Exp. 2, total tract OM and NDF digestibility and ruminai pH, total VFA, and acetate did not differ (P ≥ 0.13) among treatments. Propionate concentration was least (P = 0.001) for CON, intermediate for PI69, and greatest for PROP. Conversely, A:P ratio was greatest (P < 0.004) for CON, intermediate for BACT, and least for PROP. Acetate clearance did not differ (P = 0.69) among treatments. Propionibacterium acidi-propionici PI69 increased IVDMD and total VFA of low-quality forage. Supplementation with PA and calcium propionate salts increased propionate and decreased A:P in the rumen. Supplementation of PA represents a potential way to increase ruminai propionate concentration when dormant forages are fed. [ABSTRACT FROM AUTHOR]

Pathogenic bacteria can live asymptomatically within and on cattle and can enter the food chain but also can be transmitted to humans by fecal or direct animal contact. Reducing pathogenic bacterial incidence and populations within live cattle represents an important step in improving food safety. A broad range of preslaughter intervention strategies are being developed, which can be loosely classified as 1) directly antipathogen strategies, 2) competitive enhancement strategies (that use the microbiome's competitive nature against pathogens), and 3) animal management strategies. Included within these broad categories are such diverse methods as vaccination against foodborne pathogens, probiotics and prebiotics, bacterial viruses (i.e., bacteriophages), sodium chlorate feeding, and dietary and management changes that specifically alter the microbiome. The simultaneous application of 1 or more preharvest strategies has the potential to reduce human foodborne illnesses by erecting multiple hurdles preventing entry into humans. However, economic factors that govern producer profitability must be kept in mind while improving food safety. [ABSTRACT FROM AUTHOR]

The qseBC-encoded quorum-sensing system regulates the motility of Escherichia coli O157:H7 in response to bacterial autoinducer 3 (AI-3) and the mammalian stress hormones epinephrine (E) and norepinephrine (NE). The qseC gene encodes a sensory kinase that autophosphorylates in response to AI-3, E, or NE and subsequently phosphorylates its cognate response regulator QseB. In the absence of QseC, QseB downregulates bacterial motility and virulence in animal models. In this study, we found that 8- to 10-month-old calves orally inoculated with a mixture of E. coli O157:H7 and its isogenic qseBC mutant showed significantly higher fecal shedding of the qseBC mutant. In vitro analysis revealed similar growth profiles and motilities of the qseBC mutant and the parental strain in the presence or absence of NE. The magnitudes of the response to NE and expression of flagellar genes flhD and fliC were also similar for the qseBC mutant and the parental strain. The expression of ler (a positive regulator of the locus of enterocyte effacement [LEE]), the ler-regulated espA gene, and the csgA gene (encoding curli fimbriae) was increased in the qseBC mutant compared to the parental strain. On the other hand, growth, motility, and transcription of flhD, fliC, ler, espA, and csgA were significantly reduced in the qseBC mutant complemented with a plasmid-cloned copy of the qseBC genes. Thus, in vitro motility and gene expression data indicate that the near-parental level of motility, ability to respond to NE, and enhanced expression of LEE and curli genes might in part be responsible for increased colonization and fecal shedding of the qseBC mutant in calves. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine and compare the effects of monensin, both alone and together with dietary fat, on ruminal bacterial communities in dairy cattle fed the following 3 diets: a control diet, the control diet supplemented with monensin, and the control diet supplemented with both monensin and fat. Bacterial communities in the liquid and the adherent fractions of rumen content were analyzed using 454 pyrosequencing analysis of 16S rRNA gene amplicons. Most sequences were assigned to phyla Firmicutes and Bacteroidetes, irrespective of diets and fractions. Prevotella was the most dominant genus, but most sequences could not be classified at the genus level. The proportion of Gram-positive Firmicutes was reduced by 4.5% in response to monensin but increased by 12.8% by combination of monensin and fat, compared with the control diet. Some of the operational taxonomic units in Firmicutes and Bacteroidetes were also affected by monensin or by the combination of monensin with fat. The proportion of numerous bacteria potentially involved in lipolysis and (or) biohydrogenation was increased by both monensin and fat. The Shannon diversity index was decreased in the control diet supplemented with both monensin and fat, compared with the other 2 diet groups. Supplementary fats hinder bacterial attachment to plant particles and then result in decreased bacterial diversity in the rumen. The finding of this study may help in understanding the effect of monensin and fat on ruminant nutrition and the adverse effect of monensin and fat, such as milk fat depression and decreased feed digestibility. [ABSTRACT FROM AUTHOR]

This study investigated the effects of various dietary forage-to-concentrate ratios (F:C) on urinary excretion of purine derivatives (PD) and microbial nitrogen (MN) yields from the rumen of Dorper×thin-tailed Han crossbred sheep. Twelve Dorper×thin-tailed Han crossbred ram lambs (47.2±1.0kg) fitted with ruminal and duodenal cannulae were randomly assigned to 12 levels of dietary F:C in an incomplete Latin-square experimental design (12 lambs×4 periods). Digestibility trials were conducted and MN was estimated using either 15N or PD as markers. Urinary excretion of allantoin and total PD increased (P<0.05) with decreasing F:C. Urinary excretion of uric acid or xanthine plus hypoxanthine was unaffected by F:C (P>0.05). MN yields estimated using 15N as a marker were greater than those predicted from urinary PD (12.5 vs. 11.5g/d, P<0.05), but the former was more variable than the latter (S.E.=0.66 vs. 0.45, respectively). A linear correlation existed between MN estimated by 15N and urinary excretion of PD: MN (g/d)=–0.521+1.493×PD (mmol/d) (r 2=0.86, P<0.05). The purine nitrogen index (PNI: PD nitrogen/urinary N) was linearly correlated with nitrogen capture efficiency calculated from either 15N or PD (r 2=0.60 and 0.77, respectively). Results suggest that urinary PD is an accurate indicator of MN from the rumen of Dorper crossbred sheep, and PNI reflected the conversion of nitrogen degradation to MN in the rumen. [ABSTRACT FROM AUTHOR]

Highlights: [•] Haemonchus placei is an abomasal parasite of cattle. [•] This parasite primarily occurs in summer rainfall areas of the world. [•] Here we show that H. placei also occurs in a winter rainfall area of Australia. [ABSTRACT FROM AUTHOR]

Background: In order to verify the existence of an anthrax outbreak, determine its scope, grasp the epidemiological characteristics and find out the cause of the outbreak and recommend preventive and control measures., Methods: Etiological hypothesis was developed through descriptive epidemiological methods. Hypotheses were tested by analyzing epidemiological methods by comparing the differences in the incidence of different exposure types. Nucleic acid detection and bacterial isolation and culture in the BSL-2 laboratories. SPSS 21 was used to conduct statistical analysis., Results: A total of 126 family, workshop, shop environment samples and meat samples were collected, and 6 samples were collected from skin lesions of suspected cutaneous anthrax cases. 41 samples were positive by rPCR and 8 strains of Bacillus anthracis were cultivated. Participated in slaughtering, cutting beef of sick cattles was significantly associated with cutaneous anthrax (RR 3.75, 95% CI 1.08-13.07), this behavior is extremely dangerous., Conclusions: Comprehensive analysis of laboratory results and epidemiological survey results and environmental assessments, we judge this epidemic to be an outbreak of cutaneous anthrax, associated with slaughtering and other processes from infected cattle imported from other province., (© 2022. The Author(s).)

Zoonotic pathogens are a frequent cause of disease worldwide. This study was designed to determine the occurrence of Clostridium difficile, Clostridium botulinum, and Yersinia enterocolitica in cattle in southern Bavaria, Germany. The study population included 49 farms; 34 were dairy farms (30 also fattening beef cattle) and 15 were solely beef cattle farms. Fecal and dust samples were collected from summer 2011 to summer 2012 and analyzed using a combination of enrichment procedures and real-time PCR. For the detection of C. difficile, samples were screened for the presence of the tpi gene and toxin genes tcdA, tcdB, and cdtA. Samples also were screened for genes for C. botulinum toxins A through F and for the ail gene of Y. enterocolitica. Of 506 samples, C. difficile genes were found in 29 samples (5.7%): 25 samples from dairy farms and 4 samples from beef cattle farms. Toxin genes were identified in 17 samples, with toxigenic profiles of A+B+CDT-, A+B-CDT+, and A+BCDT+. C. botulinum toxin genes were not detected in fecal samples from cattle, but the gene for toxin B was detected in 1 (0.8%) of 125 dust samples. Y. enterocolitica genes were found in 6 (1.6%) of 382 fecal samples from three dairy farms and one beef cattle farm. This study revealed that C. difficile and Y. enterocolitica are rare on cattle farms in Bavaria, Germany. In contrast to results of previous studies, C. botulinum was not detected in fecal samples but was found very rarely in dust samples from the cattle environment. [ABSTRACT FROM AUTHOR]

Abstract: In the present study the efficacy Botulism vaccine (formalinised aluminum hydroxide gel adsorbed toxoid of Clostridium botulinum types C and D) was evaluated in four Danish dairy cows under field conditions. Other four dairy herds were unvaccinated. Blood serum of all animals was analyzed for specific C. botulinum types A, B, C, D and E antibodies using a developed ELISA. Feces of all animals were analyzed for botulinum neurotoxins (BoNTs) and C. botulinum spores. C. botulinum types C and D antibodies were significantly (p < 0.05) increased in vaccinated animals. Vaccination with botulism vaccine significantly reduced (p < 0.001) BoNTs and C. botulinum spores in cattle feces. Our findings represent that C. botulinum vaccination increases specific blood serum antibodies and reduces free BoNTs and C. botulinum spores in feces. [Copyright &y& Elsevier]

The spreading of antimicrobial-resistant bacteria and genes from food-producing animals to humans has been a subject of increasing concern. To clarify the role of flies in spreading the extended-spectrum β-lactamase (ESBL) gene from food-producing animals to humans, we isolated and characterized a third-generation cephalosporin-resistant Escherichia coli strain from flies and cattle feces from a cattle barn. Cephalosporinresistant strains were isolated from 14.3% (13/91) of houseflies, 10.3% (7/68) of false stable flies, and 7.5% (7/93) of cattle feces. Twenty-seven cephalosporin-resistant strains were tested for the presence of antimicrobial resistance genes. Of the 27 samples, 22 isolates from 11 houseflies, 5 false stable flies, and 6 cattle feces samples harbored the blaCTX-M-15 gene. All blaCTX-M-15-harboring isolates belonged to phylogenetic group D and the ST38 clonal group. Analysis of pulsed-field gel electrophoresis showed that these isolates were divided into two clusters, indicating that flies carried several of the same clones that were detected in cattle feces. All blaCTXM- 15 gene-harboring plasmids were transferable and were members of incompatibility group FIB. These results suggest that transferable plasmids encoding ESBL were prevalent among flies and cattle. As vectors, flies may play an important role in spreading ESBL-producing bacteria from food-producing animals to humans. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigate the impacts of E. Coli O157:H7 recalls on the cattle futures prices. [•] E. Coli O157:H7 recalls have adverse impacts on the cattle futures prices. [•] The impacts of recalls are short-lived. [ABSTRACT FROM AUTHOR]

Abstract: A three-year trial was performed in south-western Sweden to compare animal performance and levels of parasite control in three grazing groups, each with 18–24 first-season grazing (FSG) calves in similar set-stocked pasture enclosures. These groups were subjected to: (1) no parasite control (NT), (2) monthly repeated doramectin (Dectomax®) injections (SP), or (3) targeted selective weight gain-based anthelmintic treatments (TST) but only when individual calf performance was inferior to the average of the poorer 50% of those calves in group SP. In each year, weight and parasitological variables were measured at turn-out and then at predetermined intervals for 22–24 weeks during the grazing season. The dewormed calves in group SP had a higher average weight gain at housing (range 0.39–0.61kg/day) than those in TST (0.36–0.50kg/day), which in turn always exceeded the NT group (0.23–0.42kg/day). This indicates that the parasite challenge in the NT group was sufficiently high to result in production loss. However, the average cumulative faecal egg counts (FEC) at housing in NT were in the range 1271–1953 eggs per gram faeces (epg) and in TST 1221–1968epg. In contrast, parasite eggs were rarely recorded in group SP and then only during the first two years (on average 12 and 38epg). There were also no significant differences in FEC or serum pepsinogen levels between FSG in groups NT and TST. The animals in SP received 7 doses of doramectin each year, whereas those in TST received an average of 0.5 doses. Thus, the TST approach represented a 92% reduction in anthelmintic use. The average weight gain in animals subjected to TST was always significantly lower than in animals dewormed regularly. In addition, there were no signs of short-term selection for anthelmintic resistance in the group SP animals, despite the fairly intensive use of injectable doramectin. [Copyright &y& Elsevier]

Abstract: Cryptosporidiosis is a disease reported in both humans and animals and is caused by a protozoan parasite Cryptosporidium. In most cases calves are infected by different Cryptosporidium species adapted to this animal host. Most infections are subclinical; however in some cases the watery diarrhea appears. The rapid development of new molecular diagnostic tools has provided an opportunity for better recognition of Cryptosporidium species and genotypes isolated from infected hosts. The aim of this study was an assessment of the prevalence of Cryptosporidium species in cattle herds in Poland. In total, 700 cattle fecal samples were tested. The examined cattle were at the age of 1 day to 6 years old. Overall 194 farms were monitored for parasite presence. Cryptosporidium detection in animal feces was performed using only molecular methods. Species identity of oocyst-positive samples were defined on the basis of PCR-RFLP and nucleotide sequence analysis of the amplified 18 SSU rRNA and COWP gene fragments. Cryptosporidium oocysts were detected in 119 (17%) of cattle feces. Most of the positive feces 55 (19.7%) were derived from young animals at the age of 1–4 weeks. The tested samples were positive for Cryptosporidium bovis, Cryptosporidium parvum, Cryptosporidium andersoni, and Cryptosporidium ryanae. C. parvum was not the most frequently detected parasite species, but calves below the age of 1 month were the major host for this parasite. The overall prevalence of C. parvum in Polish cattle herds was estimated at 5.1%. C. andersoni was the only species occurring in adult calves. The infected animals were housed in 67 (34.5%) of the monitored homesteads. Although C. bovis and C. ryanae were previously detected in cattle populations in many countries, this is the first report describing their presence in Polish cattle. Moreover, this is the first report on the prevalence of Cryptosporidium species in Polish cattle herds. [Copyright &y& Elsevier]

Abstract: Tick-borne disease is one of the most harmful tropical diseases in dairy production. Selection of dairy cows for tolerance to tick-borne disease is a challenging concept for dairy breeders in the tropics. The objectives of this study were (1) to detect specific tick-borne pathogen in cattle of different genetics and (2) to examine the polymorphisms of DRB3.2 alleles in Thai dairy cattle and find the allelic association with tick-borne disease tolerance. Specific primers to Anaplasma marginale (AM), Babesia bigemina (BG) and Babesia bovis (BB) were used to detect the infections by PCR. The results showed that the high proportion of infections were found in Bos indicus (Sahiwal, n =95) and crossbred Holstein×Zebu (75:25 Holstein:Zebu, n =101), compared to high Holstein fraction crossbreed (≥87.5% Holstein, n =187). The proportion of triple infections was also highly found in high Holstein fractions crossbreed. This study confirmed that Zebuine (Bos indicus) had a higher degree of tolerance, even when infected by tick-borne pathogens, compared to high Holstein fraction crossbred. The associated alleles of DRB3.2 for tick-borne pathogen infection tolerance were found: DRB3*14 and *41 were found to be tolerant to A. marginale; *14 to B. bovis; and *10 and *51 to B. bigemina. These tolerance alleles could be used as potential markers for selection in dairy genetic evaluation. The associated alleles for susceptibility were also found: *2 was found to be susceptible to A. marginale; *3 and *16 to B. bovis; and *20 to B. bigemina. These susceptibility alleles could be used as markers for culling, and selection favoring susceptibility alleles should be considered to maintain heterozygote advantage and pathogen-specific memories in the herd. [Copyright &y& Elsevier]

The objective of this study was to use 15N to label microbial cells to allow development of equations for estimating the microbial contamination in ruminai in situ incubation residues of forage produced under tropical conditions. A total of 24 tropical forages were ruminai incubated in 3 steers at 3 separate times. To determine microbial contamination of the incubated residues, ruminai bacteria were labeled with 15N by continuous intraruminal infusion 60 h before the first incubation and continued until the last day of incubation. Ruminai digesta was collected for the isolation of bacteria before the first infusion of 15N on adaptation period and after the infusion of 15N on collection period. To determine the microbial contamination of CP fractions, restricted models were compared with the full model using the model identity test. Avalué of the corrected fraction "A" was estimated from the corresponding noncorrected fraction by this equation: Corrected "A" fraction (ACPC) = 1.99286 + 0.98256 x A" fraction without correction (ACPWC). The corrected fraction "B" was estimated from the corresponding noncorrected fraction and from CP, NDF, neutral detergent insoluble protein (NDIP), and indigestible NDF (iNDF) using the equation corrected "B" fraction (BcpC) = -17.2181 - 0.0344 x fraction "B" without correction (BcpWC) + 0.65433 x CP + 1.03787 x NDF + 2.66010 x NDIP - 0.85979 x iNDF. The corrected degradation rate of "B" fraction (kd)was estimated using the equation corrected degradation rate of "B" fraction (kdCPC) = 0.04667 + 0.35139 x degradation rate of "B" fraction without correction (kdCPWC) + 0.0020 x CP - 0.00055839 x NDF - 0.00336 x NDIP + 0.00075089 x iNDF. This equation was obtained to estimate the contamination using CP of the feeds: %C = 79.21 x (1 - e-°0555t) x e-0.0874CP jt was concluded that A and B fractions and kd of CP could be highly biased by microbial CP contamination, and therefore these corrected values could be obtained mathematically, replacing the use of microbial markers. The percentage of contamination and the corrected apparent degradability of CP could be obtained from values of CP and time of incubation for each feed, which could reduce cost and labor involved when using 15N. [ABSTRACT FROM AUTHOR]

Aim: To isolate and identify Shigella species from faecal samples based on cultural and biochemical tests. Material and Methods: For the isolation of Shigella spp., faecal samples from cattle, poultry and humans were collected from various locations of Pantnagar. Fecal specimens were processed according to standard protocols. Results: Out of 511 fecal samples (311 human, 100 cattle and 100 poultry faecal samples) analyzed, 8 isolates of Shigella species were confirmed on the basis of Gram stain, morphology, cultural identification and biochemical characters. All the 8 Shigella isolates were obtained from human stool samples giving a prevalence rate of 2.57%. Conclusion: Under the conditions of the current study, Shigella species were prevalent in human population although in small numbers, whereas it was not isolated from cattle and poultry samples. [ABSTRACT FROM AUTHOR]

Feeding ability and productive yield was evaluated in male cattle under restricted grazing for 90 days during the dry period. Twenty four animals (commercial Zebu) were used with a mean live weight of 359.24 ± 1.09 kg, grazing in 20 ha with different supplementation levels. A completely randomized design was applied with the following treatments: I) grazing, II) grazing plus 1.5 kg of distiller maize grains (DDGS), III) grazing plus 2.5 kg DDGS. The activities: ingestion, rumination, rest, water intake and inactivity were analyzed. The frequency of the activities between each hour of the day and average daily gain (ADG) were determined. Data were processed with INFOSTAT and through ComparPro version I. In treatment I animals devoted more time (P < 0.001) to ingestion and less (P < 0.001) to rumination regarding the remaining activities (6.88; 5.73 and 5.09 h and 0.58; 0.99 and 1.28 h) for ingestion and rumination in treatments I, II and III, respectively. The ingestion frequency of pastures showed between 8:00 and 9:00 a.m. higher (P < 0.001) amount of animals grazing. Treatment I (71%) was superior by 9 and 21% to treatments II and III, respectively. ADG was conditioned by the supplementation level. The use of DDGS decreased the ingestion time, increased rumination and improved ADG in the treatment with the highest supplementation level. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the normal conjunctival bacterial flora and the effects of sex and age variations on them in healthy cattle in Urmia, Iran. The animals (n = 50) were selected from 2 sexes and divided into 2 age groups. Swabs were taken from the inferior conjunctival sac of both eyes (n = 100) and were cultured on blood and MacConkey agar. All (100%) of the specimens yielded positive bacterial isolations. The bacterial isolates (in order of decreasing frequency) were Lactobacillus plantarum, Escherichia coli, Bacillus cereus, Proteus mirabilis, Enterobacter aerogenes, Staphylococcus epidermidis, and S. aureus. There was no significant difference in number of isolates between sexes and age groups (P > 0.05). In the present study L. plantarum, as a normal flora organism, was reported from the conjunctival sac in cattle for the first time. [ABSTRACT FROM AUTHOR]

The mammalian gut microbiota is essential in shaping many of its host's functional attributes. One such microbiota resides in the bovine digestive tract in a compartment termed as the rumen. The rumen microbiota is necessary for the proper physiological development of the rumen and for the animal's ability to digest and convert plant mass into food products, making it highly significant to humans. The establishment of this microbial population and the changes occurring with the host's age are important for understanding this key microbial community. Despite its importance, little information about colonization of the microbial populations in newborn animals, and the gradual changes occurring thereafter, exists. Here, we characterized the overall bovine ruminal bacterial populations of five age groups, from 1-day-old calves to 2-year-old cows. We describe the changes occurring in the rumen ecosystem after birth, reflected by a decline in aerobic and facultative anaerobic taxa and an increase in anaerobic ones. Some rumen bacteria that are essential for mature rumen function could be detected as early as 1 day after birth, long before the rumen is active or even before ingestion of plant material occurs. The diversity and within-group similarity increased with age, suggesting a more diverse but homogeneous and specific mature community, compared with the more heterogeneous and less diverse primary community. In addition, a convergence toward a mature bacterial arrangement with age was observed. These findings have also been reported for human gut microbiota, suggesting that similar forces drive the establishment of gut microbiotas in these two distinct mammalian digestive systems. [ABSTRACT FROM AUTHOR]

Long polar fimbriae ( Lpf) are intestinal adhesins and important virulence factors of pathogenic Escherichia coli strains. We cloned and sequenced the lpf2-1 operon ( lpf2ABCD ) and its flanking regions of an intimin- and Shiga toxin-negative atypical E. coli O157: H43 strain of bovine origin and also sequenced the lpf2-1 operon of six additional atypical O157 bovine E. coli strains of various serotypes. Nucleotide sequence comparison of these lpf operons showed sequence conservation as they contained only four polymorphic nucleotide positions. Investigation of these O157 strains as well as 13 E. coli Reference Collection ( ECOR) strains carrying the lpf2-1 allele revealed high degree of sequence conservation in the lpf2 flanking regions. The lpf2-1 allele is also present in a bovine Shiga toxin-producing E. coli STEC O136: H12 strain, and in vitro adherence assays revealed that the absence of lpf2-1 in this strain did not affect its host cell-binding properties. Our data indicate that lpf2 loci are highly conserved in E. coli isolates; however, its role in adherence might be masked by other uncharacterized adhesins. [ABSTRACT FROM AUTHOR]

Abstract: A total of 812 samples from bovine hides and the corresponding carcasses collected at the slaughterhouse level in the eastern part of Poland were examined for the presence of Campylobacter jejuni and Campylobacter coli. Recovered isolates were confirmed using species-specific PCR, characterized by the presence of 11 putative virulence genes and antimicrobial susceptibility was determined using a microbroth dilution method. Furthermore, the genotypic relatedness of the isolates was determined by PFGE profiling and virulence pattern cluster analysis. The prevalence of Campylobacter was 25.6% and 2.7% in bovine hide and carcass samples, respectively. The presence of virulence markers varied between C. jejuni and C. coli species however, the majority of strains possessed the cadF, flhA, flaA genes, irrespective of the bacterial species and origin. The lower number of the strains was positive for the invasive associated markers –virB11 and wlaN. Antibiotic profiling showed that campylobacters were most frequently resistant to quinolones and fluoroquinolones (nalidixic acid and ciprofloxacin, 38.3% of each, respectively) followed by streptomycin (24.3%) and tetracycline (20.9%). Resistance to erythromycin and gentamicin was demonstrated in 4.3% and 2.6% of strains, respectively. Comparisons of the PFGE and virulence marker profiles of the isolates reflected the high genetic diversity of Campylobacter tested. Moreover, a poor correlation between the PFGE type, pathogenic gene marker and antimicrobial resistance patterns was observed. [Copyright &y& Elsevier]

Several mastitis-causing pathogens are able to colonize the bovine teat canal. The objective of this study was to investigate the association between the treatment of sawdust bedding with a commercial alkaline conditioner and the bacterial counts on teat skin and in the teat canal. The study used a crossover design. Ten lactating Holstein cows that were free of udder infections and mastitis were included in the study. The animals were bedded on either untreated sawdust or sawdust that had been treated with a hydrated lime-based conditioner. Once a day, fresh bedding material was added. After 3 weeks, the bedding material was removed from the cubicles, fresh bedding material was provided, and the cows were rotated between the two bedding material groups. Teat skin and teat canals were sampled using the wet and dry swab technique after weeks 1, 2, 3, 4, 5 and 6. Staphylococcus aureus, Streptococcus uberis, Escherichia coli and other coliform bacteria were detected in the resulting agar plate cultures. The treatment of the bedding material was associated with the teat skin bacterial counts of Str. uberis, Esch. coli and other coliform bacteria. An association was also found between the bedding material and the teat canal bacterial counts of coliform bacteria other than Esch. coli. For Staph. aureus, no associations with the bedding material were found. In general, the addition of a hydrated lime-based conditioner to sawdust reduces the population sizes of environmental pathogens on teat skin and in teat canals. [ABSTRACT FROM AUTHOR]

Abstract: Healthy cattle and their environment are the reservoir for the human pathogen Escherichia coli O157. In E. coli O157 epidemiology, supershedders have been loosely defined as cattle that shed high concentrations of E. coli O157 (≥104 colony-forming cells (CFU)/g of feces) at a single (or multiple) cross-section in time. Due to the variability in the pathogen shedding level among animals (between-host variability), as well as fluctuations in the level shed by a single animal (within-host variability), it is difficult to interpret fecal bacteria distributions, as well as to parse the relative contribution of between- and within-host variability to the observed shedding patterns at the pen level. We developed an agent-based model that integrates individual animal data on temporal fecal shedding dynamics with pen-level E. coli O157 transmission to study how the temporal (and aggregation) patterns of E. coli O157 shedding loads and prevalence arise at the pen level. We demonstrated that even without between-host variability, the prevalence of animals with concentration of E. coli O157 in feces that exceeds 104 CFU/g is similar to that observed in cross-sectional field data. Both within-host and between-host variability can generate supershedders. [Copyright &y& Elsevier]

Bovine Viral Diarrhea-Mucosal Disease (BVD-MD) is a widely spread infectious disease that causes important economic losses in farms. Several epidemiological studies indicate a high genetic heterogeneity among Bovine Viral Diarrhea Virus (BVDV) strains circulating in Italy. The aim of this study was to investigate the genotypes of BVDV in Sicily, a region in the South of Italy. For this purpose, 17 BVDV strains collected from cattle breed in Sicily between 2005 and 2008 were genetically typed by sequencing of the 5′-untraslated region (5′-UTR) of the viral genome. In this study, phylogenetic analysis showed that all 17 examined strains were clustered within the BVDV genotype 1. Particularly, 14 of them were clustered with the BVDV-1b subgroup, while the remaining three strains were clustered with the BVDV-1e. Moreover, the restriction analysis indicated a bovine origin for all of the 17 strains typed in this study. These results could be useful to carry out an epidemiological survey and to create vaccines that protect cattle against BVDV different subgroups. [ABSTRACT FROM AUTHOR]

To establish environmental contamination in and around a dairy barn, cows shedding Mycobacterium avium ssp. paratuberculosis (MAP) were housed in a freestall barn. Fecal samples were collected 15 times at 3-wk intervals, and samples of all animals were cultured by using the Trek Diagnostic Systems culture system (Cleveland, OH) to quantify levels of MAP shedding. In parallel, air and floor dust samples were collected inside and outside the experimental farm and analyzed by IS900 real-time PCR for the presence of MAP DNA. Inside the barn, MAP was detected with equal frequency in samples directly contaminated with feces compared with air dust samples above animal level and in dust samples of the corridor. Dust samples collected within the barn were positive more frequently than outside samples, with exception of the outside sample from the farmer's doormat. The risk of MAP exposure was distributed evenly within the dairy barn. Additionally, footwear should be considered as a high-risk fomite for dispersion of dust-related MAP outside the barn. Prevention of MAP exposure in youngstock may require housing of youngstock in separate barns as an additional management measure. [ABSTRACT FROM AUTHOR]

Bacteriological culture (BC) is the traditional method for intramammary infection diagnosis but lacks sensitivity and is time consuming. Multiplex real-time PCR (mr-PCR) enables testing the presence of several bacteria and reduces diagnosis time. Our objective was to estimate bacterial species-specific sensitivity (Se) and specificity of both BC and mr-PCR tests for detecting bacteria in milk samples from clinical mastitis cases and from apparently normal quarters, using a Bayesian latent class model. Milk samples from 1,014 clinical mastitis cases and 1,495 samples from apparently normal quarters were analyzed by BC and mr-PCR. Two positive culture definitions were used: ≥1 cfu/0.01 mL and ≥10 cfu/0.01 mL of the specified bacteria. The mr-PCR was designed to simultaneously detect Staphylococcus aureus, Streptococcus uberis, Escherichia coli, and Streptococcus agalactiae. The priors used in our Bayesian model were weakly informative, with BC priors using the best available error data. Results were compared with those obtained using uniform priors for mr-PCR to test robustness. Weak and uniform priors gave about the same posterior distributions except for Strep. uberis from normal quarters and Strep. agalactiae. Multiplex real-time PCR Se on milk from clinical mastitis were lower than mr-PCR Se on milk from normal quarters. Multiplex real-time PCR Se was higher than BC on milk from normal quarters. Multiplex real-time PCR Se was generally lower than BC on milk from clinical mastitis and it varied by clinical severity. The estimate specificities of detection for all pathogens were ≥99%, regardless of sample type. The effect of milk sample preservation before testing was evaluated and may have been a factor that affected our observed results. A significant association was observed between sample age and mr-PCR results leading to reduced detection of E. coli and Strep. agalactiae in nonclinical samples. Differences in sample age between conduct of BC and of mr-PCR did not concur with any apparent differences between Se estimates of the 2 tests. Further work should be done to extend these results to other PCR-based tests for detecting bacterial species in milk samples, for which presented results could be used as prior parameter distributions. Limits of sample handling and storage and the potential existence of substances in clinical case samples that may interfere with PCR reactions also are worth further investigation. [ABSTRACT FROM AUTHOR]

The molecular fingerprints of 878 isolates of Mycobacterium bovis from cattle, mostly dairy cattle, collected from cattle between 2009 and 2010 in different regions of Mexico were obtained by spoligotyping. Seventy-two percent (72 %) of the spoligotypes fell into nine clusters, and 27 % of the isolates fell into only two spoligotypes; 149 were orphan spoligotypes. The two predominant spoligotypes, arbitrarily designated as SP1 and SP2, were found in almost all States in Mexico, especially in central Mexico, where a concentration of dairy cattle is known. In spite of the wide distribution of spoligotypes observed, some show high regional preference, especially those in geographically distant regions. Only a few spoligotypes show patterns completely different from those shown by the most frequent spoligotypes, suggesting strange sources of infection or the formation of new genetic lines derived from non-lethal mutations. Most States with predominantly high dairy cattle populations showed similar spoligotypes, suggesting exchange of animals between regions. Some spoligotypes are common to dairy and beef cattle, suggesting transmission between populations, most probably due to the movement of dairy cattle to non-dairy regions. [ABSTRACT FROM AUTHOR]

Se obtuvieron patrones moleculares (espoligotipos) de 878 aislados de Mycobacterium bovis de ganado de diferentes regiones de México entre los años 2009 y 2010. Setenta y dos por ciento (72 %) de los espoligotipos cayeron en nueve grupos y 27 % de los aislados dentro de sólo dos espoligotipos; 149 fueron espoligotipos individuales. Los dos espoligotipos predominantes, arbitrariamente identificados como SP1 y SP2, se distribuyen en la mayor parte del territorio nacional, en especial en la zona centro de México en ganado especializado en producción de leche. A pesar de la amplia distribución geográfica de los espoligotipos de mayor frecuencia, algunos muestran cierta localización, en especial los encontrados en zonas geográficas distantes, como es el caso de Chihuahua y Baja California. Aunque pocos, algunos espoligotipos muestran patrones moleculares distintos a los mostrados por los espoligotipos de mayor frecuencia, sugiriendo fuentes de infección desconocida. La mayoría de los Estados con ganadería predominantemente lechera muestran espoligotipos comunes, lo que sugiere intercambio regional frecuente de ganado. Algunos espoligotipos son comunes en ganado para leche y ganado para carne, lo que sugiere transmisión entre estas dos poblaciones; se desconoce, sin embargo, si los animales de carne infectados provienen de explotaciones extensivas o si son de engordas ubicadas dentro de la explotación lechera. Se propone la tipificación rutinaria de aislados de M. bovis obtenidos en todos los laboratorios de diagnóstico y mejorar la captura de información epidemiológica de los casos, para hacer mejores conclusiones epidemiológicas de la distribución espacial de las cepas de este agente en el territorio nacional. [ABSTRACT FROM AUTHOR]

Abstract: We evaluated whether a bovine intestinal epithelial (BIE) cell line could serve as a useful in vitro model system for studying antiviral immune responses in bovine intestinal epithelial cells (IECs) and for the primary screening of immunobiotic microorganisms with antiviral protective capabilities. Immunofluorescent analyses revealed that toll-like receptor 3 (TLR3) was expressed in BIE cells, and the results of real-time quantitative PCR showed that these cells respond to stimulation with poly(I:C) by up-regulating pro-inflammatory cytokines and type I interferons. In addition, we demonstrated that BIE cells are useful for the primary screening of immunobiotic lactic acid bacteria strains which are able to beneficially modulate antiviral immune responses triggered by TLR3 activation in bovine IECs. The characterization of BIE cells performed in the present study represents an important step towards the establishment of a valuable bovine in vitro system that could be used for the development of immunomodulatory feed for bovine hosts. [Copyright &y& Elsevier]

Microbial protein synthesis is essential to meet protein requirements in ruminants. The aim of this investigation was to evaluate the effect of incorporating extruded corn (Zea mays L.) into the ration of young steers fed with grass silage on microbial protein synthesis (MPS). Twenty young steers in metabolic cages were used for supplying food. The treatments consisted of combinations of extruded corn (EC) and ground corn (GC) EC-10 (10% EC-30% GC); EC-25 (25% EC-15% GC) and EC-40 (40% EC-0% GC). These foods constituted 40% of the ration (DM-based) and the remaining 60% was grass silage. The MPS was calculated through the excretion of purine derivatives (PD) in the urine, using total collection of urine. The inclusion of a higher percentage of extruded corn (EC-40) increased the PD excretion (51.85 mmol d-1, P < 0.05). The values of PD excretion ranged between 663 and 1078 µmol BW-0.75d-1. The microbial protein absorption and flow of duodenal N also increased with a higher portion of extruded corn (EC-40, P < 0.05). The differences between treatments can be explained by the effect of corn extruding. This allows more energy available for ruminal bacteria and improved synchrony between energy and protein. [ABSTRACT FROM AUTHOR]

Dairy cattle selected for negative residual feed intake (n-RFI; efficient) should maintain production while reducing dry matter intake over a lactation because of improvements in feed digestion and efficient use of nutrients. The objective of this study was to measure nitrogen (N) digestibility and rumen microbial community composition over a short period during early lactation in lactating Holstein-Friesian cows selected previously for divergent RFI. It was proposed that n- RFI cows would have greater apparent digestibility of N than the positive RFI (p-RFI; inefficient) animals, to compensate for the lower dry matter intake determined during selection for divergence. Sixteen 3-yr-old rumencannulated, lactating cows (56 ± 10 d in milk) selected for n-RFI (n = 8) and p-RFI (n = 8) were housed in metabolism stalls and fed fresh vegetative ryegrass (Lolium perenne L.) pasture ad libitum as a sole diet during an 8-d digestibility study. Intake of nutrients and outputs of milk, feces, and urine were determined. Rumen parameters were determined by removing, weighing, and sampling digesta, and by cobalt-EDTA dilution. Intakes of N, dry matter, organic matter, or its components did not differ with RFI. Compared with p-RFI cows, n-RFI cows had a greater apparent N digestibility (77.2 vs. 75.5%), and a tendency toward greater dry matter and organic matter digestibilities. The n-RFI cows had a lower fecal N output (126 vs. 138 g/d) and a lower partition of feed N to fecal N (23.1 vs. 24.7%) compared with p-RFI animals. We found no differences between phenotypes in the partition of N to urinary N or milk crude protein but did observe a trend for n-RFI cows to partition less N to milk casein (16.8 vs. 17.9%). Rumen digesta mass was similar for both groups, despite differences in calculated fractional liquid outflow rates, and most bacterial, archaeal, protozoal, and fungal communities were similar for both phenotype groups. In conclusion, dry matter intake and rumen function were similar for both phenotypes when the animals were fed highly digestible fresh ryegrass, but apparent digestibility of dietary N was higher in the efficient (n-RFI) cows. Future research should measure digestion parameters in cows with divergent RFI when fed diets differing in chemical composition (e.g., divergent crude protein contents). [ABSTRACT FROM AUTHOR]

Abstract: Dogs have been employed to protect an array of resources from various species of offending wildlife. Historically, livestock protection dogs (LPDs) protected domestic sheep and goats from predators based on development of a strong bond between protected and protector. Within reason, developing that bond between a LPD and other species of livestock should be achievable. We conducted several studies in which we raised and bonded LPDs with bovine calves and evaluated them for protecting cattle in a variety of settings. Though successful strategies in developing LPDs to protect cattle were similar to those established for sheep, we found differences that were important for optimizing the process. Here we outline our strategies for developing LPDs for maintaining separation between cattle and wild ungulates that are reservoirs of disease that cattle are susceptible to as well as wild carnivores that are predators of cattle. [Copyright &y& Elsevier]