Occurrence and molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi in dairy cattle,beef cattle and water buffaloes in China

Cryptosporidium spp. and Enterocytozoon bieneusi are important protists in a wide range of vertebrate hosts, causing diarrheal diseases. Cattle are considered potential reservoirs of Cryptosporidium infection in humans, although their role in the transmission of E. bieneusi is not clear. In the present work, 793 fecal specimens from dairy cattle, native beef cattle, and water buffaloes on 11 farms in China were examined for the presence of Cryptosporidium spp. and E. bieneusi using nested PCR targeting the small subunit (SSU) rRNA gene of Cryptosporidium spp. and the internal transcribed spacer (ITS) of E. bieneusi. For Cryptosporidium, 144/446 (32.3%) dairy cattle, 44/166 (26.5%) beef cattle, and 43/181 (23.8%) water buffaloes were PCR-positive. Sequence analysis was successful for 213 of the 231 Cryptosporidium-positive isolates; among them 94 had Cryptosporidium andersoni, 61 had Cryptosporidium bovis, 54 had Cryptosporidium ryanae, 2 had a Cryptosporidium suis-like genotype, and 2 had mixed infections of C. bovis and C. ryanae. In dairy and beef cattle, C. andersoni and C. bovis were the most common species, whereas C. ryanae was the dominant species in water buffaloes. The latter species produced SSU rRNA sequences different between cattle and water buffaloes. For E. bieneusi, the infection rate of E. bieneusi in dairy cattle, beef cattle and water buffaloes was 4.9%, 5.4% and 2.2%, respectively. All 35 E. bieneusi-positive specimens were successfully sequenced, revealing the presence of four genotypes: three Group 2 genotypes previously reported in cattle as well as humans (I, J and BEB4) and one Group 1 genotype recently reported in yaks (CHN11). Genotypes I and J were the most common genotypes in dairy and beef cattle, while genotype CHN11 was the only genotype seen in water buffaloes. Thus, the distribution of Cryptosporidium spp. and E. bieneusi in water buffaloes might be different from in dairy and beef cattle in China. These findings indicate that some of the Cryptosporidium species and all four E. bieneusi genotypes identified in bovine animals in the study areas may have zoonotic potential.     

Cryptosporidium scrofarum n. sp. (Apicomplexa: Cryptosporidiidae) in domestic pigs (Sus scrofa)

We describe the morphological, biological, and molecular characteristics of Cryptosporidium pig genotype II and propose the species name Cryptosporidium scrofarum n. sp. to reflect its prevalence in adult pigs worldwide. Oocysts of C. scrofarum are morphologically indistinguishable from C. parvum, measuring 4.81–5.96 μm (mean = 5.16) × 4.23–5.29 μm (mean = 4.83) with a length to width ratio of 1.07 ± 0.06 (n = 400). Oocysts of C. scrofarum obtained from a naturally infected pig were infectious for 8-week-old pigs but not 4-week-old pigs. The prepatent period in 8-week-old Cryptosporidium-naive pigs was 4–6 days and the patent period was longer than 30 days. The infection intensity of C. scrofarum in pigs was generally low, in the range 250–4000 oocysts per gram of feces. Infected pigs showed no clinical signs of cryptosporidiosis and no pathology was detected. Cryptosporidium scrofarum was not infectious for adult SCID mice, adult BALB/c mice, Mongolian gerbils (Meriones unguiculatus), southern multimammate mice (Mastomys coucha), yellow-necked mice (Apodemus flavicollis), or guinea pigs (Cavia porcellus). Phylogenetic analyses based on small subunit rRNA, actin, and heat shock protein 70 gene sequences revealed that C. scrofarum is genetically distinct from all known Cryptosporidium species.     

Apparent seroprevalence,isolation and identification of risk factors for brucellosis among dairy cattle in Goa,India

Brucellosis is a highly contagious zoonotic infection affecting livestock and human beings. The disease has been reported worldwide except in few countries where it has been eradicated. The prevalence of brucellosis among cattle from 11 farms having a history of abortions was studied. A total of 481 samples comprising of blood, milk, vaginal swabs, vaginal discharges, placental tissues and fetal tissues were collected from 296 animals. Clinical samples were processed for the isolation of Brucella. Serum samples (n = 296) were tested by Rose Bengal Plate Test (RBPT) and indirect ELISA. A total of 90 (30.40%) and 123 (41.55%) samples were positive by RBPT and indirect ELISA, respectively. Also 27.02% samples were positive by both the tests. Brucella isolates (n = 8) were recovered from clinical samples using Brucella selective media. All the isolates demonstrated PCR amplification for the bcsp31 and IS711 genes. Amplification of Brucella abortus specific primer was demonstrated by all the isolates in AMOS PCR indicating isolates to be of either B. abortus biotype 1, 2 or 4. Risk factors for transmission of brucellosis among cattle population were studied by field surveys. It was observed that lack of awareness about brucellosis (OR = 8.739, P = 0.138) and inadequate floor space (OR = 0.278, P = 0.128) were crucial risk factors for transmission of bovine brucellosis.     

Occurrence of Cryptosporidium and Giardia on beef farms and water sources within the vicinity of the farms on Prince Edward Island, Canada

The objectives of this study were to determine the prevalence and assemblages of Giardia and species of Cryptosporidium on beef farms in Prince Edward Island (PEI), Canada, including the water sources associated with the farms, and to determine risk factors for infection of cattle with these parasites. Twenty beef farms were selected based on the presence of surface water < 500 m from the barn. Prevalence was determined by direct immunofluorescence microscopy, while genotyping and species determination were performed by nested-PCR and DNA sequencing. Giardia was detected in 42% (95% CI: 38-46%) of fecal samples from 100% farms while Cryptosporidium was detected in 17% (95% CI: 14-19%) of fecal samples from 80% of farms. The most predominant Giardia assemblage isolated was the livestock specific assemblage E (89%). The zoonotic assemblages A and B were found in 4 and 7% of the Giardia isolates that were genotyped, respectively. The Giardia assemblages were detected equally between the cows and calves examined. Overall, the most common Cryptosporidium species detected in this study was Cryptosporidium andersoni (49%), predominantly found in cattle >6 mo of age, while most Cryptosporidium bovis and Cryptosporidium pestis (previously Cryptosporidium parvum ‘bovine genotype’) isolates were detected in calves ≤ 6 mo of age. All Cryptosporidium ryanae isolates (four) were found in calves. Giardia cysts and Cryptosporidium oocysts were detected in 14 and 93% of surface water samples of 14 farms, respectively. Cryptosporidium oocysts were detected in three (15%) ground water samples of 20 farms. One Cryptosporidium-positive water sample, which was the only surface water sample amenable to genotyping, contained C. parvum. The farm-level risk factors investigated in this study, age of animals and location of the farm, were not associated with the risk of infection in cattle with either Cryptosporidium spp. or Giardia duodenalis.We conclude that beef cattle are a potential reservoir of Cryptosporidium spp. and G. duodenalis that could contaminate source water. There is the possibility of further transmission to humans on PEI if the source water is not properly treated prior to consumption.     

Giardia and Cryptosporidium infections in neonatal reindeer calves: Relation to the acute phase response

This longitudinal observational study was conducted to investigate the spontaneous effect of Giardia and Cryptosporidium infections on acute phase response (APR) in reindeer calves (Rangifer tarandus tarandus) in Finnish Lapland.Serum (n = 609) and faecal samples (n = 366) were collected from 54 reindeer calves aged zero to 33 days. The samples were analysed for Giardia, Cryptosporidium, acute phase proteins (APP) and γ-globulins.Linear regression models were used to investigate associations of early Giardia infection (before 12 days of life) with the response of APPs and acquiring of passive immunity.Giardia was detected in 100% and Cryptosporidium in 23% of calves. There was a negative association between early Giardia infection and γ-globulin concentrations (p = 0.032) and a positive association with serum amyloid A (SAA) concentrations (p = 0.042). The results suggest a protective effect of colostrum against Giardia infection and that early infection may induce activation of APR.     

Identity and public health potential of Cryptosporidium spp. in water buffalo calves in Egypt

Little is known about the diversity and public health significance of Cryptosporidium species in water buffaloes. In this study, we examined the distribution of Cryptosporidium spp. in water buffalo calves in Egypt. Rectal fecal specimens from 179 calves and 359 adults were screened microscopically for Cryptosporidium oocysts using modified Ziehl–Neelsen stain. Cryptosporidium spp. in 17 microscopy-positive specimens from calves were genotyped by DNA sequence analysis of the small-subunit rRNA gene, and Cryptosporidium parvum was subtyped by sequence analysis of the 60 kDa glycoprotein gene. Cryptosporidium ryanae was found in 10 specimens and C. parvum in 7 specimens, with the former belonging to the newly identified C. ryanae buffalo variant and the latter belonging to the subtypes IIdA20G1 (in 5 specimens) and IIaA15G1R1 (in 2 specimens). The prevailing occurrence of C. ryanae and the subtype family IId of C. parvum and the absence of C. bovis and C. andersoni represent some features of Cryptosporidium transmission in water buffaloes in Egypt.     

Immune and inflammatory responses in pigs infected with Trichuris suis and Oesophagostomum dentatum

The aim of the present study was to investigate parasite induced immune responses in pigs co-infected with Trichuris suis and Oesophagostomum dentatum as compared to mono-species infected pigs. T. suis is known to elicit a strong immune response leading to rapid expulsion, and a strong antagonistic effect on O. dentatum populations has been observed in co-infected pigs. Forty-eight helminth naïve pigs were allocated into 4 groups in a 2-factorial design. Two groups were trickle inoculated with either 10 T. suis eggs/kg/day (Group T) or 20 O. dentatum L3/kg/day (Group O). Group OT was infected with same levels of both T. suis and O. dentatum (Group OT) and Group C remained uninfected. In each group, six pigs were necropsied after 35 days and the remaining pigs after 71 days. Parasite E/S-antigen specific serum antibodies were quantified by an in-direct ELISA. qPCR was used to measure the expression of immune function related genes in the mucosa of proximal colon and the draining lymph node. Highly significant interactions were identified for O. dentatum specific IgG1 (p < 0.0001) and IgG2 (p < 0.0006) antibodies with a remarkable 2-fold higher antibody response in group OT pigs as compared to group O. These findings indicated that T. suis enhanced the antibody response against O. dentatum in Group OT. The gene expression data confirmed a strong Type 2 response to T. suis (e.g. marked increase in IL-13, ARG1 and CCL11) and clearly weaker in amplitude and/or delayed onset response to O. dentatum in the single infected group. Interactions were found between the two nematodes with regard to several cytokines, e.g. the increase in IL-13 observed in Group T was absent in Group OT (p = 0.06, proximal colon mucosa, 35 and 71 p.i.). Some of these immune response-related interactions may support, or even partially explain, the observed interactions between the two worm populations in co-infected pigs.     

Infection by Paramphistomidae trematodes in cattle from two agricultural regions in NW Uruguay and NW Spain

The analysis of infection by Paramphistomidae trematodes was conducted in two agricultural regions with different knowledge on this parasitosis. Faecal and blood samples were collected from 374 cattle in Salto (NW Uruguay) where there is a lack of information about paramphistomosis. A total of 429 cattle from Galicia (NW Spain), an area with previous records of infection by gastric flukes, were sampled. Diagnostics of trematodosis was developed by using a copromicroscopic probe and an ELISA with excretory/secretory antigens collected from adult Calicophoron daubneyi (Paramphistomidae) specimens. Results were evaluated according intrinsic and extrinsic factors.In the Uruguay, the percentage of cattle passing Paramphistomidae-eggs by faeces was 7% (95% Confidence Interval 5, 10). A significantly higher prevalence of paramphistomosis in the Hereford × Angus cattle (OR = 3.5) was recorded, as observed for the oldest ruminants (>3.5 years). An overall seroprevalence of 29% (25, 34) was obtained by ELISA, with the highest values in the Friesians (OR = 3), the youngest bovines (<2.5 years) and dairy cattle (Friesians).Twenty-six percent (22, 30) of the cattle from Spain passed eggs by faeces, and cattle aged 2.5–7 years reached significant highest prevalences. By means of the ELISA, a percentage of 55 cattle (50, 59) had antibodies against the gastric fluke, and the highest seroprevalence was observed among the bovines under 6 years.It is concluded that paramphistomosis is on the increase in cattle from NW Spain, partly due to the absence of an effective treatment against the trematode. There is a need for reducing the risk of infection by Paramhistomidae spp. in cattle from Uruguay, especially by improving their management to avoid exposure to the gastric trematode. Further studies are in progress for identifying the species of Paramphistomidae affecting ruminants in Uruguay.     

Statewide Cross-Sectional Survey of Cryptosporidium and Giardia in California Cow-Calf Herds

Cryptosporidium spp. and Giardia duodenalis are common protozoal parasites in livestock including beef cattle on rangeland and irrigated pasture. A statewide cross-sectional study was conducted to determine the prevalence, species or genotype, and risk factors for fecal shedding of Cryptosporidium and Giardia by cattle from California cow-calf operations. Species and genotypes of Cryptosporidium and Giardia were determined by molecular fingerprinting. Prevalence of Cryptosporidium (19.8%) and Giardia (41.7%) in fecal samples from calves were approximately twice as high as fecal samples from cows (9.2% and 23.1%, respectively). In addition to age, multivariable logistic regression showed that higher stocking density and a higher number of replacement heifers were positively associated with fecal shedding of Cryptosporidium while longer calving interval, a winter/spring calving season, and higher numbers of replacement heifers were positively associated with shedding of Giardia. The dominant species and genotypes of Cryptosporidium and Giardia in feces from these cow-calf herds were Cryptosporidium ryanae (75%) and assemblage E for Giardia duodenalis (90%), which have low impact on public health compared with other zoonotic species/genotypes of these two parasites. We identified host and potential management practices that can be used to protect cattle health and reduce the risk of surface water contamination with protozoal parasites from cow-calf operations. In addition, this work updated the scientific data regarding the predominance of low zoonotic genotypes of Cryptosporidium and Giardia shed in the feces of commercial cow-calf herds on California rangeland and irrigated pasture.     

Does Cattle Grazing Affect Ant Abundance and Diversity in Temperate Grasslands?

Half of the world's land base is grazed by domesticated livestock. Because of the important functional role of ants in grasslands, it is important to understand the effect of livestock grazing on ant abundance and diversity. The objectives of this study were to examine the effect of cattle grazing and site productivity on the abundance, species richness, and species diversity of ants in Lac du Bois Grasslands Provincial Park, British Columbia, Canada. We hypothesized that the measured ant variables would be lowest in grazed areas and at low site productivity. Pitfall trapping was conducted at four sites: two at each low and high site productivity levels. At each site an ungrazed (fenced exclosure) and grazed transect was sampled during May, July, and August of 2008. Captured ants were preserved in ethanol and identified. Eight genuses of ants were collected: Tapinoma, Camponotus, Formica, Lasius, Aphaenogaster, Myrmica, Solinopsis, and Temnotharox. The mean number of ants per pitfall was higher at high site productivity sites that were grazed (15.10 ±  SE) compared to high productivity sites ungrazed (3.28 ±  SE); grazing at low productivity reduced numbers of ants from 5.07 (± 0.70 SE) to 2.20 (± 0.39 SE) (F = 21.806; P [ 0.001). Tapinoma sessile and A. occidentalis had the greatest numbers in the pitfall traps. Species richness (F = 23.330, P [ 0.001) and diversity (F = 11.764, P = 0.001) followed a similar trend. Because productivity and cattle grazing affect ant diversity and abundance, and ants impact ecosystem functioning, these factors should be considered in management of grasslands.     

Characterization of colonization-deficient mutants of Actinobacillus suis

Actinobacillus suis is an important opportunistic pathogen of swine that can cause disease in pigs of all ages, especially in high-health status herds. Although A. suis shares many virulence factors in common with Actinobacillus pleuropneumoniae and can cause a haemorrhagic pleuropneumonia similar to that caused by A. pleuropneumoniae, A. suis most often causes septicaemia and diseases such as arthritis and meningitis that are sequelae to septicaemia. In a recent signature-tagged transposon mutagenesis study, 30 colonization-essential genes of A. suis were identified. In the current study, the attachment and invasion patterns of strains harboring Tn10 insertions in ompA, pfhaB1, lcbB, and cpxR were evaluated using porcine palatine tonsil organ cultures, the swine kidney epithelial cell line, SK6, and a porcine brain microvascular endothelial cell line, PBMEC/C1-2. All of these mutants attached in lower numbers than wild type to the tonsillar explants and to the SK6 cells. The ompA mutant attached in significantly lower numbers than wild type to the porcine tonsil cells (P = 0.02) and to PBMEC (P = 0.0008) at 60 min time point. As well, the ompA mutant showed significantly greater sensitivity than wild type to chemical stressors and to swine serum. Using fluorescent microscopy, a GST-OmpA fusion protein could be demonstrated to interact with the crypt epithelial cells of porcine palatine tonsil.     

Development of colloidal gold-based immunochromatographic assay for rapid detection of Streptococcus suis serotype 2

To develop colloidal gold immunochromatographic strips for the direct detection of the Streptococcus suis serotype 2 antigen, colloidal gold was prepared by reduction of a gold salt with sodium citrate and coupled with polyclonal antibody against S. suis serotype 2. The optimal concentrations of the capture antibody and the coating antibody were determined to be 22 μg/mL and 2.0 mg/mL, respectively, and that of the blocking buffer was determined to be 1.5% bovine serum albumin. Different serotypes of S. suis and other related bacteria were used to evaluate the sensitivity, specificity, and stability of the immunochromatographic strips. The detection sensitivity was found to be as high as 10⁶ CFU/mL. There was no cross-reaction of the antibodies with other serotypes of S. suis (except with SS1/2, which shares some common sugar residues or antigenic determinants with serotype 2) and other related bacteria. In conclusion, we developed colloidal gold immunochromatographic strips that had high sensitivity and specificity. This method proved to be feasible, convenient, rapid, and effective for detecting S. suis serotype 2.     

Molecular biological identification of Babesia,Theileria, and Anaplasma species in cattle in Egypt using PCR assays,gene sequence analysis and a novel DNA microarray

In this preliminary study, a novel DNA microarray system was tested for the diagnosis of bovine piroplasmosis and anaplasmosis in comparison with microscopy and PCR assay results. In the Dakahlia Governorate, Egypt, 164 cattle were investigated for the presence of piroplasms and Anaplasma species. All investigated cattle were clinically examined. Blood samples were screened for the presence of blood parasites using microscopy and PCR assays. Seventy-one animals were acutely ill, whereas 93 were apparently healthy. In acutely ill cattle, Babesia/Theileria species (n = 11) and Anaplasma marginale (n = 10) were detected. Mixed infections with Babesia/Theileria spp. and A. marginale were present in two further cases. A. marginale infections were also detected in apparently healthy subjects (n = 23). The results of PCR assays were confirmed by DNA sequencing. All samples that were positive by PCR for Babesia/Theileria spp. gave also positive results in the microarray analysis. The microarray chips identified Babesia bovis (n = 12) and Babesia bigemina (n = 2). Cattle with babesiosis were likely to have hemoglobinuria and nervous signs when compared to those with anaplasmosis that frequently had bloody feces. We conclude that clinical examination in combination with microscopy are still very useful in diagnosing acute cases of babesiosis and anaplasmosis, but a combination of molecular biological diagnostic assays will detect even asymptomatic carriers. In perspective, parallel detection of Babesia/Theileria spp. and A. marginale infections using a single microarray system will be a valuable improvement.     

Landscape risk factors for attacks of vampire bats on cattle in Sao Paulo,Brazil

Vampire-bat (Desmodus rotundus) attacks on cattle are a major concern for cattle-raising area. Blood loss and paralytic rabies due to bat bites can impose severe losses on the livestock. We took four municipalities inside the Sao Joao da Boa Vista veterinary district (Sao Paulo, Brazil) as a study area and tested a set of landscape features for spatial correlation with distance to areas in which vampire-bat attacks on cattle were documented. Bat- and cattle-related data from the Sao Paulo State Rabies Control Program were used. Landscape data (first-order rivers and their tributaries, main roads, railways and urban areas) were obtained from official cartographic agencies; forest, sugarcane and pasture data were acquired from remote-sensing mappings. The study area was taken as a grid split into 178 cells. Each 4 km × 4 km cell was filled with bat, cattle and landscape data. Our analysis detected that grid cells that were closer to areas of bat attacks on cattle had higher cattle density and a greater percentage of the land committed to sugarcane cropping, and were close to forest fragments. These results shed light on the need for rethink the Rabies Control Program strategies for defining the surveillance of vampire-bat populations and rabies control in the state of Sao Paulo, Brazil.     

Consumption of Low Larkspur (Delphinium nuttallianum) by Grazing Sheep

Low larkspur (Delphinium nuttallianum Pritz.) poisoning causes serious economic loss to livestock producers that graze cattle on foothill and mountain ranges in western North America. In general, all Delphinium spp. are five times less toxic to sheep than to cattle. Because low larkspurs are less toxic to sheep than cattle, grazing sheep before cattle on rangelands with dense populations of low larkspur can reduce larkspur density and risk of poisoning to grazing cattle. All previous published work on sheep and larkspur interactions has involved tall larkspurs. This series of studies was conducted to determine if sheep would consume sufficient low larkspur to reduce subsequent risk to cattle. Four summer trials were conducted in Collbran, Colorado, and Soda Springs, Idaho on pastures with dense (> 9 plants · m^?2) low larkspur populations. In all trials, sheep ate very little low larkspur (< 0.5% of bites). During one final trial using high sheep density (two sheep · 0.015 ha^?1 for 9 d), sheep consumed little low larkspur, but animals appeared to trample much of the low larkspur. Toxic alkaloid concentrations in low larkspur ranged from 1.1 mg · g^?1 to 1.6 mg · g^?1 in all trials. The use of sheep to graze low larkspurs to reduce subsequent consumption by grazing cattle does not appear to be a viable option.     

Occurrence of Giardia and Cryptosporidium in pigs on Prince Edward Island, Canada

In a cross-sectional study of 633 pigs from 21 herds on Prince Edward Island, Canada (PEI), the prevalence of infection with Cryptosporidium and Giardia, and the genotypes and species of isolates were determined in order to establish the zoonotic potential of pigs in this region. As determined by direct immunofluorescence microscopy (DFA), 18 herds (86%) and 163 animals (26%; 95% CI: 22-29%) tested positive for Cryptosporidium, while just 3 herds (14%) and 6 animals (1%; 95% CI: 0.4-2%) tested positive for Giardia. Cryptosporidium spp. isolates were detected in 39% (95% CI: 34-44%) of weanlings (1-3 months of age) and 9% (95% CI: 6-13) of sows (>8 months of age). Molecular characterization using the 18S rDNA and HSP70 gene fragments revealed the presence of Cryptosporidium sp. pig genotype II, C. suis, C. parvum, and Cryptosporidium sp. mouse genotype. Among the 113 isolates of Cryptosporidium spp. successfully genotyped, pig genotype II (61%) predominated, with C. suis (36%) being the next most prominant isolate. C. parvum (2%; two isolates) and Cryptosporidium sp. mouse genotype (0.9%; one isolate) were only occasionally isolated. The only two Cryptosporidium-positive genotyped isolates from sows included one each of C. suis and Cryptosporidium sp. pig genotype II.All but one of the six Giardia positive isolates were detected in weanling pigs. None of the Giardia-positive isolates was amenable to PCR. This study demonstrates that Cryptosporidium spp. are highly prevalent in pigs on PEI, Canada, are found mostly in weanlings (1-3 months of age). Furthermore, the pigs are primarily infected by the host-specific genotypes and species, Cryptosporidium sp. pig genotype II and C. suis, whereas the zoonotic C. parvum is rare. Giardia duodenalis is only occasionally found in pigs. These findings suggest that domestic pigs on PEI, Canada, likely do not pose a significant health risk to humans from these parasites.     

Blood-feeding patterns of horse flies in the French Pyrenees

Horse flies can mechanically transmit Besnoitia besnoiti, the agent of bovine besnoitiosis. Although previously limited to enzootic areas, especially the French Pyrenees Mountains, bovine besnoitiosis is now considered a re-emerging disease in western Europe. To improve understanding of the role of horse flies as mechanical vectors, this study investigated their blood-feeding ecology in the eastern French Pyrenees, in two high-altitude summer pastures whose main domestic ungulates were cattle, and in a wildlife park with native fauna. Species-specific PCR assays were conducted to identify the sources of blood meals: wild boar, horse, cattle (or bison), sheep (or mouflon), goat, red deer, roe deer and izard (or Pyrenean chamois). In La Mouline pasture, tabanids (N = 20) fed on red deer (70%) and cattle (30%). In Mantet pasture, tabanids (N = 24) fed on cattle (52%), red deer (20%), wild boar (16%), horse (8%) and sheep (4%). In the wildlife park, Tabanus bromius (N = 32), the most abundant species collected, fed on red deer (85%), bison (9%) and wild boar (6%). Despite relatively high densities in both the pastures and in the wildlife park, small wild ungulates (izard, mouflon and roe deer) were not detected as a source of blood meals. Only two mixed blood meals were identified in two specimens of T. bromius: cattle/horse for the specimen collected in the pastures, and bison/wild boar for the specimen collected in the wildlife park. Our findings showed that tabanids display a level of opportunistic feeding behaviour, in addition to a preference for red deer, the latter being particularly true for Philipomyia aprica, the most abundant species collected in the pastures.     

Stocking Rate and Fuels Reduction Effects on Beef Cattle Diet Composition and Quality

An experiment was conducted to evaluate the influence of forest fuels reduction on diet quality, botanical composition, relative preference, and foraging efficiency of beef cattle grazing at different stocking rates. A split plot factorial design was used, with whole plots (3 ha) being fuel reduced or no treatment (control), and split plots (1 ha) within whole plots were grazed to three levels of forage utilization; (low) 3 heifers · ha^?1, (moderate) 6 heifers · ha^?1, (high) 9 heifers · ha^?1, with a 48-h grazing duration. Grazing treatments were applied in August of 2005 and 2006. Cattle diet composition and masticate samples were collected during 20-min grazing bouts using six ruminally cannulated cows in each experimental unit. Relative preference indices indicated a strong preference for grass regardless of treatment and stocking rate. Grass consumption was lower in control pastures (P < 0.05) and tended (P < 0.095) to decrease with increased stocking rates. Shrub use was higher in control pastures displaying a quadratic effect (P < 0.05) due to stocking, whereas shrub use increased with stocking rate across all treatments. Cattle grazing control pastures consumed diets higher in crude protein compared to cattle grazing treated pastures (P < 0.05). In vitro dry matter digestibility values were lower (P < 0.05) in control sites and tended (P = 0.10) to decrease with increased stocking rates. In both control and treated pastures, bites per minute and grams consumed per minute declined (P = 0.003) with increased stocking, indicating foraging efficiency of cattle decreases with increased stocking rates. Our data indicated cattle grazing late season grand fir habitat types have a strong preference for grasses regardless of treatment or stocking rate. However, as stocking rate increased in both control and treated pastures, grass consumption decreased, shrub consumption increased, and foraging efficiency decreased.     

Antimicrobial resistant Escherichia coli isolates in cattle and house sparrows on two Czech dairy farms

Rectal smears of calves, cows and young bulls, as well as cloacal smears of house sparrows (Passer domesticus), from farms at the villages of Šumice and Troskotovice, Czech Republic, were examined for E. coli resistant to 12 antimicrobials. The resistant isolates were tested for antimicrobial-resistance genes and integrons. Totals of 40% (n = 183), 3% (n = 95), 0% (n = 33), and 9% (n = 54) of Escherichia coli isolates from calves, cows, young bulls and house sparrows, respectively, were antimicrobial resistant. The following genes were identified in cattle E. coli isolates: tetA, tetB (isolates resistant to tetracycline), bla_TEM (beta-lactams), strA, aadA (streptomycin), sul1, sul2 (sulphonamides), and cat, floR (chloramphenicol). Seven of 16 antimicrobial-resistant calf isolates from the Šumice farm possessed class 1 integrons with the aadA1 gene cassette integrated, 1 kb in size. On the Troskotovice farm, eight of 57 antimicrobial-resistant calf isolates possessed class 1 integrons. Integrons of 1.5 kb with the dhfr1- aadA1 gene cassette were found in four isolates, followed by a 1 kb integron with the aadA1 gene found in three isolates, and a 1.7 kb integron with the dhfr17-aadA5 gene cassette and the phenotype ASSuTSxtNaCipCCfG. The prevalence of resistant E. coli in calves compared to adult cattle was much higher and probably was influenced by oral antimicrobial usage in calves, feeding with milk and colostrum from treated cows, as well as mechanisms unrelated to antimicrobial drug selection. Although house sparrows lived together with the cattle and came into contact with cattle waste on the farm, they were not infected by resistant E. coli isolates with the same characteristics as those found in cattle.     

Evaluation of Low-Stress Herding and Supplement Placement for Managing Cattle Grazing in Riparian and Upland Areas

Management practices are often needed to ensure that riparian areas are not heavily grazed by livestock. A study was conducted in Montana during midsummer to evaluate the efficacy of low-stress herding and supplement placement to manage cattle grazing in riparian areas. Three treatments were evaluated in three pastures over a 3-yr period in a Latin-square design (n = 9). Each year, naïve 2-yr-old cows with calves were randomly assigned to the three treatments: 1) free-roaming control, 2) herding from perennial streams to upland target areas, and 3) herding to upland sites with low-moisture block supplements. Stubble heights along the focal stream were higher (P = 0.07) in pastures when cattle were herded (mean ± SE, 23 ± 2 cm) than in controls (15 ± 3 cm). Global positioning system telemetry data showed that herding reduced the time cows spent near (< 100 m) perennial streams (P = 0.01) and increased the use of higher elevations (P = 0.07) compared with controls. Evening visual observations provided some evidence that free-roaming cows (44% ± 19%) were in riparian areas more frequently (P = 0.11) than herded cows (23% ± 6%). Fecal abundance along the focal stream was less (P = 0.07) with herding (61.9 ±  kg · ha⁻¹) than in controls (113.2 ±  kg · ha⁻¹). Forage utilization within 600 m of supplement sites was greater (P = 0.06) when cows were herded to low-moisture blocks (18% ± 6%) compared with controls and herding alone (8% ± 2%). Moving cattle to uplands at midday using low-stress herding is an effective tool to reduce use of riparian areas. Herding cattle to low-moisture blocks can increase grazing of nearby upland forage but may not provide additional reduction in cattle use of riparian areas compared with herding alone.