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Bingham, Howard R., Paul S. Morley, Thomas E. Wittum, Tammy M. Bray, Keith H. West, Richard D. Slemons, John A. Ellis et al. "Synergistic effects of concurrent challenge with bovine respiratory syncytial virus and 3-methylindole in calves". American Journal of Veterinary Research 60, n. 5 (1 maggio 1999): 563–70. http://dx.doi.org/10.2460/ajvr.1999.60.05.563.
Testo completoAbstract (sommario):
Abstract Objective To evaluate the potential synergy between bovine respiratory syncytial virus (BRSV) and 3-methylindole (3MI) in inducing respiratory disease in cattle. Animals 20 mixed-breed beef calves. Procedure A 2 × 2 factorial design was used, with random assignment to the following 4 treatment groups: unchallenged control, BRSV challenge exposure (5 × 104 TCID50 by aerosolization and 5.5 × 105 TCID50 by intratracheal inoculation), 3MI challenge exposure (0.1 g/kg of body weight, PO), and combined BRSV-3MI challenge exposure. Clinical examinations were performed daily. Serum 3MI concentrations, WBC counts, PCV, total plasma protein, and fibrinogen concentrations were determined throughout the experiment. Surviving cattle were euthanatized 7 days after challenge exposure. Pulmonary lesions were evaluated at postmortem examination. Results Clinical respiratory disease was more acute and severe in cattle in the BRSV-3MI challenge-exposure group than in cattle in the other groups. All 5 cattle in this group and 3 of 5 cattle treated with 3MI alone died or were euthanatized prior to termination of the experiment. Mean lung displacement volume was greatest in the BRSV-3MI challenge-exposure group. Gross and histologic examination revealed that pulmonary lesions were also most severe for cattle in this group. Conclusions and Clinical Relevance Feedlot cattle are commonly infected with BRSV, and 3MI is produced by microflora in the rumen of all cattle. Our results suggest that there is a synergy between BRSV and 3MI. Thus, controlling combined exposure may be important in preventing respiratory disease in feedlot cattle. (Am J Vet Res 1999;60:563–570)
2
Pšenka, M., M. Šístková, Š. Mihina e R. Gálik. "Frequency analysis of noise exposure of dairy cows in the process of milking". Research in Agricultural Engineering 62, No. 4 (28 novembre 2016): 185–89. http://dx.doi.org/10.17221/4/2015-rae.
Testo completoAbstract (sommario):
In the environment of farms and farm buildings, cattle are exposed to various unnatural influences. Such an impact is also noise always arising with a certain energy conversion. In cattle farms, the sources of noise are represented by various mechanical equipment and machines that are used for enabling farm operations. The aim of the paper was to analyse the noise levels in dairy cattle production in the environment, during their day routine. Noise levels were measured at two farms with a different technological layout of milking parlour, with a different way of milking. The noise exposure of dairy cows was measured in three locations, namely in the milking parlour, during standing in the area before milking (in the so-called collection room) and directly in the stabling area. Noise exposure was measured during milking and when the milking parlour was turned off. The values were compared with the hearing sensitivity of cattle at selected frequencies (0.5, 1, 2, 4, 8 and 16 kHz).
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MILLER, M. F., G. H. LONERAGAN, D. D. HARRIS, K. D. ADAMS, J. C. BROOKS e M. M. BRASHEARS. "Environmental Dust Exposure as a Factor Contributing to an Increase in Escherichia coli O157 and Salmonella Populations on Cattle Hides in Feedyards". Journal of Food Protection 71, n. 10 (1 ottobre 2008): 2078–81. http://dx.doi.org/10.4315/0362-028x-71.10.2078.
Testo completoAbstract (sommario):
A study was conducted to determine the impact of exposure to dust in the cattle load-out area in feedyards on pathogen contamination of cattle hides. A total of 250 cattle hides were sampled during summer and fall months, which are associated with elevated prevalence of Escherichia coli O157 in West Texas. Animals were removed from their home pens and restrained in a chute and sampled prior to exposure to dust generated as a result of a simulated loading exercise. The cattle hides were sampled again after exposure to the loading dust to determine total numbers of pathogens on cattle hides on leaving their home pen (before loading) and on cattle hides after exposure to the dust in the loading area. Air and dirt samples from the home pens and the cattle load-out area were also collected. The presence of E. coli O157 and Salmonella was determined in all the samples, and when a positive sample was identified, the total numbers of these bacteria present were enumerated. The total numbers of pathogens increased after dust exposure; Salmonella counts increased from 1.09 log most probable number (MPN)/cm2 to 1.74 log MPN/cm2 after exposure, and E. coli O157 counts increased from 0.80 to 2.35 log MPN/cm2 after sampling. E. coli O157 and Salmonella were recovered from the air samples during dust generation at 6.66 and 11.1%, respectively. Salmonella and E. coli O157 prevalence was not changed and was not associated with the exposure to the dust. Results indicate airborne dust generated as a result of cattle movement and loading could be an important determining factor in total numbers of pathogens recovered on cattle hides.
4
Kaufmann, Jillian, Edward W. Bork, Michael J. Alexander e Peter V. Blenis. "Effects of open-range cattle grazing on deciduous tree regeneration, damage, and mortality following patch logging". Canadian Journal of Forest Research 44, n. 7 (luglio 2014): 777–83. http://dx.doi.org/10.1139/cjfr-2014-0131.
Testo completoAbstract (sommario):
The impact of summer cattle grazing on deciduous tree regeneration within uncut forests, clearcuts, partially harvested areas, and in-block haul road habitats was examined in four experimental pastures of central Alberta during 2008 and 2009. Sampling of 233 field plots, both inside and outside cattle exclosures, was used to document sapling densities, height, and type of damage. Tree densities (primarily aspen (Populus tremuloides Michx.)) differed among habitats but less so with exposure to cattle. Densities were greatest in clearcuts, followed by partially harvested areas and then uncut forest and haul roads. While exposure to cattle reduced total tree regeneration, sapling densities and sizes remained sufficient to meet postharvest standards for deciduous forest regeneration in Alberta, even with exposure to cattle. Cattle damage in harvested areas was primarily from browsing (≤3.2% of saplings), with proportionally more trees affected in uncut forests (8.6%). Browsing was particularly high on balsam poplar (Populus balsamifera L.) (25%) during 2008. Although sapling damage increased with high cattle stocking in 2008 (to 10.5%), total mortality was limited to 15.5% through 2009. These findings show that despite cattle impacts to some saplings, damage levels were insufficient to alter deciduous regeneration, highlighting the compatibility of cattle grazing and sustainable forest management on public lands in this region.
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Rabaza, Ana, Federico Giannitti, Martín Fraga, Melissa Macías-Rioseco, Luis G. Corbellini, Franklin Riet-Correa, Darío Hirigoyen, Katy M. E. Turner e Mark C. Eisler. "Serological Evidence of Human Infection with Coxiella burnetii after Occupational Exposure to Aborting Cattle". Veterinary Sciences 8, n. 9 (16 settembre 2021): 196. http://dx.doi.org/10.3390/vetsci8090196.
Testo completoAbstract (sommario):
Cattle are broadly deemed a source of Coxiella burnetii; however, evidence reinforcing their role in human infection is scarce. Most published human Q fever outbreaks relate to exposure to small ruminants, notably goats. Anti-phase II C. burnetii IgG and IgM were measured by indirect fluorescent antibody tests in 27 farm and veterinary diagnostic laboratory workers to ascertain whether occupational exposure to cattle aborting due to C. burnetii was the probable source of exposure. Four serological profiles were identified on the basis of anti-phase II IgG and IgM titres. Profile 1, characterised by high IgM levels and concurrent, lower IgG titres (3/27; 11.1%); Profile 2, with both isotypes with IgG titres higher than IgM (2/27; 7.4%); Profile 3 with only IgG phase II (5/27; 18.5%); and Profile 4, in which neither IgM nor IgG were detected (17/27; 63.0%). Profiles 1 and 2 are suggestive of recent C. burnetii exposure, most likely 2.5–4.5 months before testing and, hence, during the window of exposure to the bovine abortions. Profile 3 suggested C. burnetii exposure that most likely predated the window of exposure to aborting cattle, while Profile 4 represented seronegative individuals and, hence, likely uninfected. This study formally linked human Q fever to exposure to C. burnetii infected cattle as a specific occupational hazard for farm and laboratory workers handling bovine aborted material.
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Yevstafieva, V., O. Kasianenko, J. Negreba, B. Kyrychko, V. Levytska e K. Havryk. "Ovicidal effectiveness of Hermecid-VS disinfectant against Trichuris spp. nematode eggs isolated from cattle". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 25, n. 110 (18 giugno 2023): 110–15. http://dx.doi.org/10.32718/nvlvet11018.
Testo completoAbstract (sommario):
The genus Trichuris is a well-known group of nematodes whose species parasitize humans and many domestic animals, including carnivores, cattle, small ruminants and pigs. These parasites in the embryonic stages of development are quite resistant to adverse environmental conditions, which poses a threat of significant spread of trichurosis in livestock farms. The aim of the work was to determine the ovicidal effectiveness of the Hermecid-VS disinfectant (Vetsintez LLC, Ukraine) on the eggs of Trichuris spp. nematodes isolated from cattle under experimental conditions. To determine the densivasive activity, the disinfectant was used in 0.1 %, 0.25 % and 0.5 % concentrations for different exposures – 10, 30 and 60 minutes. The test-culture of trichurises eggs was obtained from the feces of sick animals using the flotation method and subsequent washing in a physiological solution. According to the research results, it was established that the Hermecid-VS preparation has a high level of ovicidal efficiency against the eggs of Trichuris spp., which parasitize cattle, at a concentration of 0.25 % for exposure of 60 minutes and 0.5 % for exposures of 10–60 minutes . Under these regimes, the disinfectant ensured 100 % death of trichurises eggs at various stages of their development in vitro. Also, a high level of ovicidal efficiency was found when using Hermecid-VS at a concentration of 0.25 % for 10 min (90.91 %) and 30 min (96.59 %) exposures. A satisfactory level of ovicidal efficiency was obtained using the agent at a concentration of 0.1 % for exposures of 10, 30 and 60 minutes, where the indicators of disinfestation activity were at the level of 63.64 %, 68.18 % and 76.14 %, respectively. The obtained research results allow us to recommend the Hermecid-VS disinfectant in 0.25 % concentration for 60-minute exposure and 0.5 % concentration for 10-minute exposure for disinfestation as a component of measures to combat and prevent cattle trichurosis, as well as with for the purpose of maintaining veterinary-sanitary and epizootic well-being in livestock farms.
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Webb, L., D. J. Beaumont, R. G. Nager e D. I. McCracken. "Effects of avermectin residues in cattle dung on yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) populations in grazed pastures". Bulletin of Entomological Research 97, n. 2 (aprile 2007): 129–38. http://dx.doi.org/10.1017/s0007485307004683.
Testo completoAbstract (sommario):
AbstractThe effects of avermectin exposure on natural populations of the yellow dung fly, Scathophaga stercoraria Linnaeus, were investigated at the field scale on farms in south-west Scotland. Pastures forming the focus of the study were grazed with either untreated cattle or cattle receiving standard, manufacturer-recommended treatment regimes of an avermectin product. Flies were sampled between April and July in 2002 and 2003 using dung-baited pitfall traps. Abundance and wing asymmetry in S. stercoraria populations were examined in relation to a range of environmental and management variables (including avermectin exposure, pasture management intensity, weather and season). Data used for abundance analyses were collected in fields where treated cattle had been dosed with either doramectin or ivermectin, while the data for the asymmetry analyses were from a subset of fields where treated cattle had been dosed with doramectin only. While abundance of S. stercoraria varied significantly between years and with season, there was no difference in their abundance between fields grazed by avermectin-treated or untreated cattle. Asymmetry was significantly higher in fly populations in fields grazed by doramectin-treated cattle, suggesting that exposure to doramectin during development could have imposed some degree of environmental stress. While these results suggest that exposure to doramectin residues in dung on grazed pastures may have sublethal effects on the insects developing in that dung, there was no evident avermectin effect on the abundance of adult S. stercoraria occurring in the pastures.
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Chakraborty, Sulagna, Siyu Gao, Brian F. Allan e Rebecca Lee Smith. "Effects of cattle on vector-borne disease risk to humans: A systematic review". PLOS Neglected Tropical Diseases 17, n. 12 (19 dicembre 2023): e0011152. http://dx.doi.org/10.1371/journal.pntd.0011152.
Testo completoAbstract (sommario):
Vector-borne pathogens (VBPs) causing vector-borne diseases (VBDs) can circulate among humans, domestic animals, and wildlife, with cattle in particular serving as an important source of exposure risk to humans. The close associations between humans and cattle can facilitate the transmission of numerous VBPs, impacting public health and economic security. Published studies demonstrate that cattle can influence human exposure risk positively, negatively, or have no effect. There is a critical need to synthesize the information in the scientific literature on this subject, in order to illuminate the various ecological mechanisms that can affect VBP exposure risk in humans. Therefore, the aim of this systematic review was to review the scientific literature, provide a synthesis of the possible effects of cattle on VBP risk to humans, and propose future directions for research. This study was performed according to the PRISMA 2020 extension guidelines for systematic review. After screening 470 peer-reviewed articles published between 1999–2019 using the databases Web of Science Core Collection, PubMed Central, CABI Global Health, and Google Scholar, and utilizing forward and backward search techniques, we identified 127 papers that met inclusion criteria. Results of the systematic review indicate that cattle can be beneficial or harmful to human health with respect to VBDs depending on vector and pathogen ecology and livestock management practices. Cattle can increase risk of exposure to infections spread by tsetse flies and ticks, followed by sandflies and mosquitoes, through a variety of mechanisms. However, cattle can have a protective effect when the vector prefers to feed on cattle instead of humans and when chemical control measures (e.g., acaricides/insecticides), semio-chemicals, and other integrated vector control measures are utilized in the community. We highlight that further research is needed to determine ways in which these mechanisms may be exploited to reduce VBD risk in humans.
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Chiuya, Tatenda, Eric M. Fèvre, Noah O. Okumu, Abdullahi M. Abdi, Sandra Junglen e Christian Borgemeister. "Exposure to Arboviruses in Cattle: Seroprevalence of Rift Valley Fever, Bluetongue, and Epizootic Hemorrhagic Disease Viruses and Risk Factors in Baringo County, Kenya". Pathogens 13, n. 8 (24 luglio 2024): 613. http://dx.doi.org/10.3390/pathogens13080613.
Testo completoAbstract (sommario):
Rift Valley fever virus (RVFV) causes disease outbreaks in livestock and humans; however, its inter-epidemic circulation is poorly understood, similar to other arboviruses affecting cattle such as bluetongue virus (BTV) and epizootic hemorrhagic disease virus (EHDV). Serum samples were collected in Baringo County, Kenya from 400 cattle, accompanied by a risk factor questionnaire. Serological tests were then conducted to determine the exposure of cattle to RVFV, BTV, and EHDV. RVFV, BTV, and EHDV IgG seroprevalence rates were 15.5%, 91.5%, and 91%, respectively. Seropositivity for RVFV, BTV, and EHDV was significantly higher in adult cattle, as well as in females for RVFV. Cattle with herd owners aged between 30–39 years were less likely to be seropositive for RVFV compared to those with owners over the age of 60 years. High seroprevalence of BTV and EHDV in cattle indicates significant exposure and the subclinical circulation of these viruses, presenting a risk of outbreaks to sheep and naïve cattle. Moreover, the detection of RVFV-seropositive young cattle born after the last reported outbreak suggests inter-epidemic circulation of the virus. Overall, monitoring these arboviruses in cattle is crucial in understanding their distribution and seroprevalence during inter-epidemic periods.
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Hoesni, Facroerrozi, Silvia Erina, Sri Arnita Abu Tani e Firmansyah. "Resistance of Simmental Cattle Semen to Time Exposure at Room Temperature". Journal of Hunan University Natural Sciences 49, n. 10 (30 ottobre 2022): 8–15. http://dx.doi.org/10.55463/issn.1674-2974.49.10.2.
Testo completoAbstract (sommario):
This research aimed to determine the resistance of Simmental cattle semen with different lifting times at room temperature. It had a completely randomized design (CRD) with seven treatments and five replications. The treatments involved lifting clotted semen at different times from the surface of liquid nitrogen at room temperature: P0 (Control), P1 (straw with lifting time of 5 seconds), P2 (straw with lifting time of 10 seconds), P3 (straw with lifting time of 15 seconds), P4 (straw with lifting time of 20 seconds), P5 (straw with lifting time of 25 seconds), and P6 (straw with lifting time of 30 seconds). Observed variables were motility, percentage of life, and sperm abnormalities. Analysis of variance was used to analyze the data. Duncan's multiple range test determined the significant effect. The results showed that the placement of Simmental cattle clotted semen at room temperature with different lifting times significantly influenced the motility and percentage of sperm life (P < 0.05), but it did not impact sperm abnormality significantly (P > 0.05). The conclusion is that the placement of Simmental cattle-clotted semen up to 20 seconds under a room temperature (28-30℃) was still feasible and a favorite for artificial insemination. The novelty of this research is to find the right and appropriate time for the placement of frozen semen for Simmental cattle so that the percentage of motility and survival of spermatozoa does not change or the resistance of frozen semen of Simmental cattle is still well maintained, making it easier for inseminators perform livestock insemination in the field conditions.
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Draghi, Susanna, Nour Elhouda Fehri, Fatma Ateş, Nural Pastacı Özsobacı, Duygu Tarhan, Bengü Bilgiç, Banu Dokuzeylül et al. "Use of Hair as Matrix for Trace Elements Biomonitoring in Cattle and Roe Deer Sharing Pastures in Northern Italy". Animals 14, n. 15 (30 luglio 2024): 2209. http://dx.doi.org/10.3390/ani14152209.
Testo completoAbstract (sommario):
Intensive cattle breeding’s environmental challenges are prompting shifts to extensive, pasture-based systems, influencing nutrient and pollutant uptake. PTEs are essential and non-essential elements, regularly found in the environment and organisms, and in which unbalances lead to health issues. Hair analysis, a non-invasive method, provides retrospective PTE exposure evaluation. This study aims to understand exposure and species-specific accumulation patterns of PTEs in cattle and roe deer sharing pastures in Northern Italy using the hair analysis. Aluminum, As, Cd, Cr, Ni, Pb, Cu, Mg, Fe, and Zn were quantified through the use of ICP-OES. Findings show As levels significantly higher in roe deer due to their selective feeding, while Cd and Pb levels align with other studies. Essential elements like Cu, Fe, and Zn are lower in cattle, possibly due to diet differences. Higher Cr and Ni levels in cattle suggest contamination or physiological differences in accumulation patterns. In conclusion, hair analysis is valuable for monitoring environmental PTE exposure, highlighting significant interspecies differences and the potential of both animals as bioindicators in shared grazing areas.
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Yamaguchi, Ichiro, Kazuhiko Inoue, Masahiro Natsuhori, Chryzel Angelica B. Gonzales, Hiroshi Yasuda, Yasuhiro Nakai, Minoru Miyake e Harold M. Swartz. "L-Band Electron Paramagnetic Resonance Tooth Dosimetry Applied to Affected Cattle Teeth in Fukushima". Applied Sciences 11, n. 3 (28 gennaio 2021): 1187. http://dx.doi.org/10.3390/app11031187.
Testo completoAbstract (sommario):
We applied a non-destructive tooth dosimetry technique using L-band electron paramagnetic resonance (EPR) to assess radiation doses in cattle due to the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, which occurred 10 years ago. The radiation exposure of cattle in the area affected by the FDNPS accident was estimated retrospectively with X-band and L-band EPR devices. Characteristic radiation-induced EPR signals were obtained from the teeth of the cattle in Fukushima, confirming their exposure. The estimated doses to the teeth were found to be consistent with the dose trends estimated for individual cows, while considerable uncertainties were seen in the doses of some tooth samples. This variation might be due to errors in the accuracy of the method but also might reflect the actual exposure because the cattle may have been exposed to higher areas of radioactivity in their quest for food and/or due to irradiation from absorption of the isotopes with localization in or near the teeth. However, at a minimum, these results confirm that L-band EPR can be used for non-destructive qualitative assessment of radiation exposure to animals using their teeth, which could be very valuable. Possible causes of the uncertainties should be investigated to enhance the value of the use of this technique.
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Busch, M. A., A. Tucker e D. Robertshaw. "Interaction between cold and altitude exposure on pulmonary circulation of cattle". Journal of Applied Physiology 58, n. 3 (1 marzo 1985): 948–53. http://dx.doi.org/10.1152/jappl.1985.58.3.948.
Testo completoAbstract (sommario):
Hereford calves were exposed in a temperature-controlled hypobaric chamber to environmental temperatures of -2 to 1 degree C (cold) at altitudes of 1,524 m (resident altitude) and 3,048 m 1) to characterize the effects of cold exposure on the pulmonary circulation; 2) to examine the role of cold-induced hypoventilation on the pulmonary circulation; and 3) to examine the interaction between cold and hypoxia on the pulmonary circulation. Cold exposure produced a significant increase in pulmonary arterial pressure (Ppa), pulmonary arterial wedge pressure (Ppaw), and pulmonary vascular resistance (PVR) at both 1,524 and 3,048 m without affecting cardiac output. Concomitantly, cold exposure caused reductions in minute ventilation, respiratory rate, end-tidal O2 tension (PETO2), and arterial O2 tension (PaO2). Tidal volume, end-tidal CO2 tension, and arterial CO2 tension increased. Neither arterial pH nor O2 consumption changed during cold exposure. These results indicated that both pulmonary arterial and venous vasoconstriction were responsible for the pulmonary hypertension associated with cold exposure. Acute exposure to 3,048 m during cold exposure produced increases in Ppa and PVR that were similar to those elicited by cold exposure at 1,524. It was concluded that altitude exposure neither attenuated nor potentiated the effect of cold exposure on the pulmonary circulation; rather, altitude and cold exposure interacted additively. O2 administered during cold exposure to restore PETO2 and PaO2 to control values partially restored Ppa and PVR to control values. This suggested that a portion of the pulmonary hypertension associated with cold exposure was due to hypoxic pulmonary vasoconstriction elicited by the cold-induced alveolar hypoventilation.
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Hamir, Amir N., Robert A. Kunkle, Randall C. Cutlip, Janice M. Miller, Katherine I. O'Rourke, Elizabeth S. Williams, Michael W. Miller, Mick J. Stack, Melanie J. Chaplin e Jürgen A. Richt. "Experimental Transmission of Chronic Wasting Disease Agent from Mule Deer to Cattle by the Intracerebral Route". Journal of Veterinary Diagnostic Investigation 17, n. 3 (maggio 2005): 276–81. http://dx.doi.org/10.1177/104063870501700313.
Testo completoAbstract (sommario):
This communication reports final observations on experimental transmission of chronic wasting disease (CWD) from mule deer to cattle by the intracerebral route. Thirteen calves were inoculated intracerebrally with brain suspension from mule deer naturally affected with CWD. Three other calves were kept as uninoculated controls. The experiment was terminated 6 years after inoculation. During that time, abnormal prion protein (PrPres) was demonstrated in the central nervous system (CNS) of 5 cattle by both immunohistochemistry and Western blot. However, microscopic lesions suggestive of spongiform encephalopathy (SE) in the brains of these PrPres-positive animals were subtle in 3 cases and absent in 2 cases. Analysis of the gene encoding bovine PRNP revealed homozygosity for alleles encoding 6 octapeptide repeats, serine (S) at codon 46, and S at codon 146 in all samples. Findings of this study show that although PrPres amplification occurred after direct inoculation into the brain, none of the affected animals had classic histopathologic lesions of SE. Furthermore, only 38% of the inoculated cattle demonstrated amplification of PrPres. Although intracerebral inoculation is an unnatural route of exposure, this experiment shows that CWD transmission in cattle could have long incubation periods (up to 5 years). This finding suggests that oral exposure of cattle to CWD agent, a more natural potential route of exposure, would require not only a much larger dose of inoculum but also may not result in amplification of PrPres within CNS tissues during the normal lifespan of cattle.
15
Kubelka, Michal, Martin Anger, Antonín Pavlok, Jaroslav Kalous, Richard M. Schultz e Jan Motlík. "Activation of pig and cattle oocytes by butyrolactone I: morphological and biochemical study". Zygote 10, n. 1 (febbraio 2002): 47–57. http://dx.doi.org/10.1017/s0967199402002071.
Testo completoAbstract (sommario):
In this study a specific inhibitor of cyclin-dependent kinases (cdks), butyrolactone I (BL I), was used for activation of pig and cattle metaphase II (MII) oocytes. BL I at a concentration of 100 μM was able to induce activation of both pig and cattle MII oocytes in a manner dependent on exposure time; however, precise timing of BL I exposure was required for the best activation results. The optimum activation rates were obtained when cattle MII oocytes were treated for 5 h with BL I and subsequently for 3-11 h in control medium, and pig MII oocytes for 8 h in BL I and then for 8-16 h in control medium; the percentage of activated oocytes after such treatment varied between 55% and 74% and between 53% and 81% for cattle and pig oocytes, respectively. Shorter exposures to BL I led to re-entry of the oocytes to the metaphase state in 35-50% of oocytes, the remaining oocytes forming a pronuclear stage; longer exposure to BL I led to increased numbers of oocytes being abnormal or degenerated. The behaviour of histone H1 kinase and mitogen activated protein (MAP) kinase, also measured during the experiment, reflected the morphological changes in the oocytes: both were inactivated after BL I treatment, though the inactivation of histone H1 kinase occurred 2 h ahead of that of MAP kinase. However, in the oocytes treated for a shorter time with BL I, with the reoccurrence of condensed chromatin in proportion of the oocytes cultured in control medium after BL I treatment, both kinases became reactivated. Taken together, these results suggest the possibility of using BL I for activation and cloning experiments in both species.
16
Tsasse, Martine Augusta Flore, Henry Dilonga Meriki, Hugues Clotaire Nana Djeunga, Marius Ambe Ngwa, Henri Olivier Tatsilong Pambou, Raïssa Dongmo, Ouethy Nguessi, Joseph Kamgno, Jane-Francis Tatah Kihla Akoachere e Patrick Nguipdop-Djomo. "Exposure to bovine livestock and latent tuberculosis infection in children: Investigating the zoonotic tuberculosis potential in a large urban and peri-urban area of Cameroon". PLOS Global Public Health 4, n. 8 (26 agosto 2024): e0003669. http://dx.doi.org/10.1371/journal.pgph.0003669.
Testo completoAbstract (sommario):
Bovine tuberculosis (bTB), a neglected zoonotic disease, is endemic in cattle in many Sub-saharan African countries, yet its contribution to tuberculosis (TB) burden is understudied. Rapid urbanisation and increase in demand for animal proteins, including dairy products, increases the risk of spill over. This study compared the latent tuberculosis infection (LTBI) risk in children, a proxy-measure for recent TB infection, in children living in high cattle density areas to children from the general population in Cameroon. Cross-sectional study in the Centre Region of Cameroon in 2021, recruiting 160 children aged 2–15 years, stratified by exposure to livestock, people treated for pulmonary TB (PTB) and the general community. Veinous blood was tested for LTBI using QuantiFERON–TB Gold-Plus. Prevalence were calculated and the association to exposure and other risk factors investigated using logistic regression models. The crude LTBI prevalence were 8.2% in the general population, 7.3% in those exposed to cattle and 61% in pulmonary TB household contacts. After adjusting for confounding and sampling design, exposure to cattle and exposure to pulmonary TB were associated with higher risk of LTBI than the general population (respectively odds ratio (OR): 3.56, 95%CI: 0.34 to 37.03; and OR: 10.36, 95%CI: 3.13 to 34.21). Children frequently consuming cow milk had higher risk of LTBI (OR: 3.35; 95%CI 0.18 to 60.94). Despite limited statistical power, this study suggests that children exposed to cattle in a setting endemic for bTB had higher risk of LTBI, providing indirect evidence that Mycobacterium bovis may contribute to TB burden.
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Eid, Benjamin, David Beggs e Peter Mansell. "The Impact of Bushfire Smoke on Cattle—A Review". Animals 11, n. 3 (17 marzo 2021): 848. http://dx.doi.org/10.3390/ani11030848.
Testo completoAbstract (sommario):
In 2019–2020, a particularly bad bushfire season in Australia resulted in cattle being exposed to prolonged periods of smoke haze and reduced air quality. Bushfire smoke contains many harmful pollutants, and impacts on regions far from the fire front, with smoke haze persisting for weeks. Particulate matter (PM) is one of the major components of bushfire smoke known to have a negative impact on human health. However, little has been reported about the potential effects that bushfire smoke has on cattle exposed to smoke haze for extended periods. We explored the current literature to investigate evidence for likely effects on cattle from prolonged exposure to smoke generated from bushfires in Australia. We conducted a search for papers related to the impacts of smoke on cattle. Initial searching returned no relevant articles through either CAB Direct or PubMed databases, whilst Google Scholar provided a small number of results. The search was then expanded to look at two sub-questions: the type of pollution that is found in bushfire smoke, and the reported effects of both humans and cattle being exposed to these types of pollutants. The primary mechanism for damage due to bushfire smoke is due to small airborne particulate matter (PM). Although evidence demonstrates that PM from bushfire smoke has a measurable impact on both human mortality and cardiorespiratory morbidities, there is little evidence regarding the impact of chronic bushfire smoke exposure in cattle. We hypothesize that cattle are not severely affected by chronic exposure to smoke haze, as evidenced by the lack of reports. This may be because cattle do not tend to suffer from the co-morbidities that, in the human population, seem to be made worse by smoke and pollution. Further, small changes to background mortality rates or transient morbidity may also go unreported.
18
Rajo, Edwin Benjamin, Katherine Williams, Andrew R. Weaver, Carrie L. Pickworth, Derek Foster e Daniel H. Poole. "90 Exposure to Endophyte-Infected Tall Fescue Negatively Impacts Pulmonary Arterial Pressure in Beef Cattle". Journal of Animal Science 101, Supplement_1 (1 maggio 2023): 65–66. http://dx.doi.org/10.1093/jas/skad068.077.
Testo completoAbstract (sommario):
Abstract Fescue toxicosis negatively impacts cattle productivity. Previous data from our laboratory has demonstrated that cattle within a herd respond differently when grazing tall fescue, thus variation within a breed may provide genetic tolerance to the negative effects on performance. Fescue toxicosis results in major impacts on the cardiovascular system, thus it was hypothesized that exposure to ergot alkaloids negatively impacts pulmonary arterial pressure (PAP). The objective of this study was to examine changes in PAP and other production parameters in cattle consuming endophyte-infected tall fescue. Pregnant Angus cows (2 to 4 years; n = 65) were randomly divided to graze either endophyte-infected (EI) or novel endophyte (EN) pastures for4 consecutive weeks starting in April. Weekly measurements were collected to monitor physiological responses to consuming endophyte-infected tall fescue. In addition, PAP was measured every 4 weeks. Data were analyzed using a MIXED procedure of SAS, and statistical significance was determined at P < 0.05 and a tendency at 0.05 < P < 0.10, and evaluated the effects of treatment, age, week, and its interactions on BW, ADG, BCS, HCS, HSS and PAP. Exposure to EI did not affect BW, ADG, or BCS (P >0.05). Whereas, hair coat scores (1-5 scale) were significantly less for cattle consuming EN pastures (2.15 ± 0.05) compared with consuming EI pastures (2.31 ± 0.05; P < 0.05). Additionally, shedding scores (1-5 scale) were reduced in cattle consuming EN pastures (2.3±0.05) compared with consuming EI pastures (2.5±0.05; P< 0.05). There was a significant difference in PAP measurements in cattle exposed to EN pastures (37.16 ± 0.59 mm Hg) compared with EI pastures (31.31 ± 0.56 mm Hg; P < 0.0001). Additionally, PAP scores tended to deviate over the 14-week study between treatment groups (P = 0.0677). As expected, exposure to EI tall fescue resulted in greater HCS and HSS. However, the decrease in PAP in cattle consuming EI fescue was unexpected. Thus, further investigations are needed to examine the interaction between ergot alkaloid exposure on cardiovascular parameters such as PAP to potentially predict genetic differences in beef cattle to identify animals that would have a lower risk of developing fescue toxicosis.
19
Rajeev, Malavika, Mathew Mutinda e Vanessa O. Ezenwa. "Pathogen Exposure in Cattle at the Livestock-Wildlife Interface". EcoHealth 14, n. 3 (3 maggio 2017): 542–51. http://dx.doi.org/10.1007/s10393-017-1242-0.
Testo completo
20
HAUS-CHEYMOL, R., E. ESPIE, D. CHE, V. VAILLANT, H. DE VALK e J. C. DESENCLOS. "Association between indicators of cattle density and incidence of paediatric haemolytic – uraemic syndrome (HUS) in children under 15 years of age in France between 1996 and 2001: an ecological study". Epidemiology and Infection 134, n. 4 (22 dicembre 2005): 712–18. http://dx.doi.org/10.1017/s095026880500542x.
Testo completoAbstract (sommario):
Over the past years Shiga-like toxin-producing Escherichia coli (STEC) O157:H7 emerged as an important cause of severe gastrointestinal illnesses and haemolytic–uraemic syndrome (HUS) with up to 10% of children infected with STEC developing HUS. We conducted a geographical ecological study using the district as the statistical unit. For each district, we estimated the incidence of HUS among children <15 years for the period 1996–2001 from national HUS surveillance data and data obtained on cattle density. We used multivariate Poisson regression to quantify the relation, adjusted for covariates, between paediatric HUS incidence and exposure to cattle. In univariate analysis, a positive association was observed between several cattle-density indicators and HUS incidence. In multivariate analysis, HUS paediatric incidence was associated with dairy cattle density and the ratio of calves to children <15 years (P<0·001). Our findings are consistent with previous studies in other countries and support the recommendation to limit exposure of children to dairy cattle and manure to reduce the risk of STEC infection.
21
RICE, D. H., K. M. McMENAMIN, L. C. PRITCHETT, D. D. HANCOCK e T. E. BESSER. "Genetic subtyping of Escherichia coli O157 isolates from 41 Pacific Northwest USA cattle farms". Epidemiology and Infection 122, n. 3 (giugno 1999): 479–84. http://dx.doi.org/10.1017/s0950268899002496.
Testo completoAbstract (sommario):
Escherichia coli O157 (n = 376) from 41 cattle farms were subtyped using pulsed field gel electrophoresis of endonuclease cleaved chromosomal DNA. Cleavage with XbaI resulted in 81 subtypes. Fifty-one isolates from subtypes found in more than one herd, or in herds on multiple sample collection dates were compared using the endonuclease NotI, resulting in 23 additional subtypes. Up to 11 XbaI subtypes were found per farm with up to 7 subtypes/farm identified from a single date. Indistinguishable subtypes (both XbaI and NotI) were found to persist on 4 farms for 6–24 months. Five subtypes were found on more than one farm separated by up to 640 km. Dairy farms where cattle had moved onto the farm had a similar number of subtypes as farms with no movement of cattle, and feedlots had more subtypes than dairy farms. These data indicate that there is a mechanism for multiple herd exposure to specific subtypes, there are multiple sources of exposure for cattle on farms, and on-farm reservoirs other than cattle may exist.
22
SMITH, L. A., G. MARION, D. L. SWAIN, P. C. L. WHITE e M. R. HUTCHINGS. "Inter- and intra-specific exposure to parasites and pathogens via the faecal–oral route: a consequence of behaviour in a patchy environment". Epidemiology and Infection 137, n. 5 (24 settembre 2008): 630–43. http://dx.doi.org/10.1017/s0950268808001313.
Testo completoAbstract (sommario):
SUMMARYLivestock herbivores are at risk of inter- and intra-specific exposure to parasites/pathogens via the faecal–oral route during grazing. Each contact between livestock and faeces in the environment is a potential parasite/pathogen transmission event. Cattle grazing contact with faeces varies in relation to the species depositing the faeces and the distribution of the faeces. We used a foraging model to simulate the grazing behaviour of beef cattle in two grazing systems to compare the relative inter-specific and intra-specific exposure risks to parasites/pathogens. Overall, there is a greater level of intra-vs. inter-specific risk via the faecal–oral route. However, under certain conditions, particularly for microparasite infections, e.g. paratuberculosis in rabbits and bovine tuberculosis in badgers, wildlife may pose a significant exposure risk to parasites/pathogens. These risks can be enhanced when cattle are first turned out onto pasture and in situations where intra-specific variations in wildlife behaviour result in more dispersed defecation patterns.
23
Idris, Musadiq, Caitlin C. Gay, Ian G. Woods, Megan Sullivan, John B. Gaughan e Clive J. C. Phillips. "Automated Quantification of the Behaviour of Beef Cattle Exposed to Heat Load Conditions". Animals 13, n. 6 (22 marzo 2023): 1125. http://dx.doi.org/10.3390/ani13061125.
Testo completoAbstract (sommario):
Cattle change their behaviour in response to hot temperatures, including by engaging in stepping that indicates agitation. The automated recording of these responses would be helpful in the timely diagnosis of animals experiencing heat loading. Behavioural responses of beef cattle to hot environmental conditions were studied to investigate whether it was possible to assess behavioural responses by video-digitised image analysis. Open-source automated behavioural quantification software was used to record pixel changes in 13 beef cattle videorecorded in a climate-controlled chamber during exposure to a simulated typical heat event in Queensland, Australia. Increased digitised movement was observed during the heat event, which was related to stepping and grooming/scratching activities in standing animals. The 13 cattle were exposed in two cohorts, in which the first group of cattle (n = 6) was fed a standard finisher diet based on a high percentage of cereal grains, and the second group of cattle (n = 7) received a substituted diet in which 8% of the grains were replaced by lucerne hay. The second group displayed a smaller increase in digitised movements on exposure to heat than the first, suggesting less discomfort under hot conditions. The results suggest that cattle exposed to heat display increased movement that can be detected automatically by video digitisation software, and that replacing some cereal grain with forage in the diet of feedlot cattle may reduce the measured activity responses to the heat.
24
Thomson, Daniel U. "37 Carry-over effects of health management through the production chain". Journal of Animal Science 97, Supplement_1 (luglio 2019): 68–69. http://dx.doi.org/10.1093/jas/skz053.155.
Testo completoAbstract (sommario):
Abstract The beef supply chain has many segments for live animals and beef products. Live cattle are sold from the ranch to the stocker to the feedlot and then to the packer. Animals get sick due to an overwhelming exposure to a pathogen or a suppressed immune system. Many times, disease infections can occur in one segment of the industry but not present clinically until the cattle are stressed during transfer to a subsequent beef production segment in the supply chain. These diseases can have an impact on cattle reproductive efficiency, performance efficiency, food safety, and economics due to decrease animal health. The lack of vaccination, biosecurity, and diagnostic surveillance can result in animals being exposed to disease causing pathogens on the ranch, during marketing, or after they arrive at the feedlot. New animals entering the herd can bring diseases into a cow/calf operation. Calves leaving a cow/calf operation can carry agents such as infectious bovine rhinotracheaitis, bovine viral diarrhea, Leptospira bacteria, bovine leukosis virus and other pathogens into the stocker, backgrounder, or feedlot operation. Commingling occurs routinely in auction markets and feedlots. We can decrease disease exposure through diagnostic monitoring, biosecurity, and proper vaccination programs. We can improve the functioning immune system through preparing cattle for market transfer through animal husbandry, nutrition, comfort, and more. Health management in the beef supply chain is dependent on decreasing disease exposure and decreasing stress in cattle.
25
Bwatota, Shedrack Festo, Gabriel Mkilema Shirima, Luis E. Hernandez-Castro, Barend Mark de Clare Bronsvoort, Nick Wheelhouse, Isaac Joseph Mengele, Shabani Kiyabo Motto, Daniel Mushumbusi Komwihangilo, Eliamoni Lyatuu e Elizabeth Anne Jessie Cook. "Seroprevalence and Risk Factors for Q fever (Coxiella burnetii) Exposure in Smallholder Dairy Cattle in Tanzania". Veterinary Sciences 9, n. 12 (28 novembre 2022): 662. http://dx.doi.org/10.3390/vetsci9120662.
Testo completoAbstract (sommario):
Q fever is a zoonotic disease, resulting from infection with Coxiella burnetii. Infection in cattle can cause abortion and infertility, however, there is little epidemiological information regarding the disease in dairy cattle in Tanzania. Between July 2019 and October 2020, a serosurvey was conducted in six high dairy producing regions of Tanzania. Cattle sera were tested for antibodies to C. burnetii using an indirect enzyme-linked immunosorbent assay. A mixed effect logistic regression model identified risk factors associated with C. burnetii seropositivity. A total of 79 out of 2049 dairy cattle tested positive with an overall seroprevalence of 3.9% (95% CI 3.06–4.78) across the six regions with the highest seroprevalence in Tanga region (8.21%, 95% CI 6.0–10.89). Risk factors associated with seropositivity included: extensive feeding management (OR 2.77, 95% CI 1.25–3.77), and low precipitation below 1000 mm (OR 2.76, 95% 1.37–7.21). The disease seroprevalence is relatively low in the high dairy cattle producing regions of Tanzania. Due to the zoonotic potential of the disease, future efforts should employ a “One Health” approach to understand the epidemiology, and for interdisciplinary control to reduce the impacts on animal and human health.
26
Mohammed, F. U., S. Ibrahim, G. A. Musa, B. Y. Kaltungo, S. Danbirni e J. K. Kwaga. "Brucella infection in migratory cattle herds in Jigawa State Nigeria: A cross sectional study". Sokoto Journal of Veterinary Sciences 18, n. 4 (18 febbraio 2021): 191–94. http://dx.doi.org/10.4314/sokjvs.v18i4.2.
Testo completoAbstract (sommario):
A cross sectional study on Brucella infection was carried out in Jigawa State in order to evaluate seroprevalence and transmission exposure factors among migratory cattle herds. A total of 1,810 cattle of different ages and sexes were systematically selected from 147 herds across four agricultural zones in the State and screened using Serum Agglutination Test (SAT) while closed ended questionnaire was used to evaluate exposure factors. From the results out of the 1,810 (serum samples) (3.37%) tested positive. Females showed higher seropositivity (3.6%) to the infection, compared to males (2.7%). Cattle of age 4-5 years had the highest prevalence (7%), compared to 3-4 years (4.5%), 2-3years (2%), 1-2years (0.8%), with no positive reactor among cattle of less than one year (0%). Seropositive animals according to the locations was found to be highest in Zone III (5.2%), followed by Zone IV (3.9%) and Zone I (2.4%), and least in Zone II (1.5%). A higher herd prevalence was recorded in Zone III (29%), followed by Zone IV (21%) and Zone I (17%), with lowest in Zone II (12%). The overall herd prevalence was 20.4%. There was association between herds that do not practice quarantine, raise multiple species, share communal pastures and water points with Brucella infection (P< 0.05) and they are more likely to acquire the infection as indicated by odds ratio. In conclusion the results have indicated that Brucella infection exists in the studied herds and some exposure factors were identified. It is hereby recommended that herd owners should practice quarantine of newly purchased animals, avoid herding multiple species of animals together, carryout routine testing and minimize contacts at grazing and water points.
Keywords: Brucella, Cattle herds, Exposure factors, Jigawa State, SAT, Seroprevalence, Serum
27
Yasmeen, Roheela, Hifsa Ali Muhammad, Bushra Nisar Khan Bushra Nisar Khan, Syeda Shazia Bokhari, Uzma Rafi e Aisha Qurashi. "Microbial Diversity in Gut of Cattle Egrets (Bubulcus Ibis) On Exposure to Different Environment". Lahore Garrison University Journal of Life Sciences 3, n. 1 (22 aprile 2020): 23–30. http://dx.doi.org/10.54692/lgujls.2019.030152.
Testo completoAbstract (sommario):
Cattle egrets (Bubulcus ibis) normally nest near water and normally feed in grass or wetlands. But now, they are changing their habitat and are also seen feeding on crop fields and garbage dumping sites. The study was conducted to assess gut flora of locally matured cattle egret exposed to different environments. The sampling was carried out in winter season of 2017 at two sites of Lahore, Havalian Karbath (rural, site 1) and Mehmood Booti (urban, site 2). The microbial analysis was carried out to find out diversity in bacterial fauna present in gut (stomach and intestine) of cattle egrets. The total of eight bacterial isolates was collected from stomach and intestine of site 1 and site 2. The characteristics study of bacterial isolates was based on morphological and biochemical tests. The bacterial isolates from site 1 were noticed as Bacillus spp. and Staphylococcus spp. However, from site 2, Staphylococcus spp., Listeria spp. and Streptococcus spp. were isolated. It was concluded on morphological characterization of isolates that diverse morphology of bacteria associated with gut flora of cattle egret on exposure to different environmental sites. However, a detailed study at species level is required to identify disease causing ability of microbes.
28
JALAVA, K., J. A. JONES, T. GOODCHILD, R. CLIFTON-HADLEY, A. MITCHELL, A. STORY e J. M. WATSON. "No increase in human cases of Mycobacterium bovis disease despite resurgence of infections in cattle in the United Kingdom". Epidemiology and Infection 135, n. 1 (2 giugno 2006): 40–45. http://dx.doi.org/10.1017/s0950268806006509.
Testo completoAbstract (sommario):
A resurgence of Mycobacterium bovis infections in cattle in the United Kingdom since the 1980s has raised concern about risks to human health. Enhanced surveillance data for England, Wales and Northern Ireland between 1993 and 2003 of culture-positive human M. bovis cases identified 315 M. bovis infections; the mean annual number of cases was 28 (range 12–41). The most frequently reported exposures were consumption of unpasteurized dairy products 41/83 (49%) and exposure to cattle 45/123 (37%). Of all cases, 249 (83%) were born before 1960. Of 50 cases born after 1960, only 14 were born in the United Kingdom. Over the same time period the annual number of new herd infections increased from 332 to 1749 as derived from the UK State Veterinary Service database. In conclusion, despite a more than fivefold increase in cattle herd infections during the 1990s, there was no increase in reported human cases.
29
Mramba, R. P., e P. E. Mapunda. "Management factors associated with the prevalence of gastrointestinal parasites in cattle: A case study of small-scale farms of the Nyamagana District in Mwanza, Tanzania". Ghanaian Journal of Animal Science 14, n. 1 (17 aprile 2024): 108–19. http://dx.doi.org/10.4314/gjansci.v14i1.11.
Testo completoAbstract (sommario):
Gastrointestinal parasites constitute a significant threat to livestock development; causing sickness and, as a result, decreased output and death. The traditional extensive communal grazing system practised by pastoralists increases exposure of cattle to the infective stages of gastrointestinal parasites. Different factors, such as geographical location, management practises, and production systems, may influence the occurrence of the parasites; thus, mitigation efforts should focus on local conditions. The aim of the study was to determine factors associated with the prevalence of gastrointestinal parasites in cattle in Nyamagana district in northern Tanzania. Faecal samples were collected from 323 cattle in the study area for laboratory analysis using simple flotation and sedimentation methods. A structured questionnaire was used to collect information from the farmers on their production systems and management practises. The overall prevalence of gastrointestinal parasites was 36.4%. The prevalence of Fasciola was 37.5%, Strongyles was 25%, Taenia was 20%, Paramphistomum was 12.5%, and Schistosoma was 5%. The likelihood of cattle being infested with gastrointestinal parasites was higher in the outdoor system of cattle production compared to the indoor system (p = 0.049) and in dirty cattle enclosures (p = 0.002). Further, the likelihood of cattle being infested with parasites was lower among native farmers compared to non-native farmers (p < 0.001), where vaccination against diseases was practised (p = 0.032), and extension services were available to the farmers (p = 0.043). To reduce the prevalence of gastrointestinal parasites, a combination of different strategies that focus on improving the immune system of cattle and reducing exposure to infective stages of the parasites is necessary.
30
Hancock, D. D., T. E. Besser, M. L. Kinsel, P. I. Tarr, D. H. Rice e M. G. Paros. "The prevalence ofEscherichia coliO157.H7 in dairy and beef cattle in Washington State". Epidemiology and Infection 113, n. 2 (ottobre 1994): 199–207. http://dx.doi.org/10.1017/s0950268800051633.
Testo completoAbstract (sommario):
SUMMARYEscherichia coliO157.H7 was found in 10 of 3570 (0·28%) faecal samples from dairy cattle in 5 of 60 herds (8·3%). Several tentative associations with manure handling and feeding management practices on dairy farms were identified. Faecal/urine slurry samples, bulk milk samples, and milk filters from dairy herds were negative forE. coli0157.H7.E. coli0157.H7 was also isolated from 10 of 1412 (0·71 %) faecal samples from pastured beef cattle in 4 of 25 (16%) herds. The prevalence ofE. coli0157. H7 excretion in feedlot beef cattle was 2 of 600 (0·33 %). The identification of cattle management practices associated with colonization of cattle byE. coli0157.H7 suggests the possibility that humanE. coliO157.H7 exposure may be reduced by cattle management procedures.
31
Zhang, Yangjunna, John W. Schmidt, Terrance M. Arthur, Tommy L. Wheeler, Qi Zhang e Bing Wang. "A Farm-to-Fork Quantitative Microbial Exposure Assessment of β-Lactam-Resistant Escherichia coli among U.S. Beef Consumers". Microorganisms 10, n. 3 (19 marzo 2022): 661. http://dx.doi.org/10.3390/microorganisms10030661.
Testo completoAbstract (sommario):
Integrated quantitative descriptions of the transmission of β-lactam-resistant Escherichia coli (BR-EC) from commercial beef products to consumers are not available. Here, a quantitative microbial exposure assessment model was established to simulate the fate of BR-EC in a farm-to-fork continuum and provide an estimate of BR-EC exposure among beef consumers in the U.S. The model compared the per-serving exposures from the consumption of intact beef cuts, non-intact beef cuts, and ground beef. Additionally, scenario analysis was performed to evaluate the relative contribution of antibiotic use during beef cattle production to the level of human exposure to BR-EC. The model predicted mean numbers of BR-EC of 1.7 × 10−4, 8.7 × 10−4, and 6.9 × 10−1 CFU/serving for intact beef cuts, non-intact beef cuts, and ground beef, respectively, at the time of consumption. Sensitivity analyses using the baseline model suggested that factors related to sectors along the supply chain, i.e., feedlots, processing plants, retailers, and consumers, were all important for controlling human exposure to BR-EC. Interventions at the processing and post-processing stages are expected to be most effective. Simulation results showed that a decrease in antibiotic use among beef cattle might be associated with a reduction in exposure to BR-EC from beef consumption. However, the absolute reduction was moderate, indicating that the effectiveness of restricting antibiotic use as a standalone strategy for mitigating human exposure to BR-EC through beef consumption is still uncertain. Good cooking and hygiene practices at home and advanced safety management practices in the beef processing and post-processing continuum are more powerful approaches for reducing human exposure to antibiotic-resistant bacteria in beef products.
32
Xu, Xinxin, Zebang Xu, Bin Yang, Kangle Yi, Fang He, Ao Sun, Jianbo Li, Yang Luo e Jiakun Wang. "Assessing the Effects of Dietary Cadmium Exposure on the Gastrointestinal Tract of Beef Cattle via Microbiota and Transcriptome Profile". Animals 13, n. 19 (5 ottobre 2023): 3104. http://dx.doi.org/10.3390/ani13193104.
Testo completoAbstract (sommario):
Cadmium (Cd) is an environmental pollutant, widely existing in soil, and can be absorbed and accumulated by plants. Hunan Province exhibits the worst cadmium contamination of farmland in China. Ruminants possess an abundant microbial population in the rumen, which enables them to tolerate various poisonous plants. To investigate whether the rumen microbiota could respond to Cd and mitigate the toxicity of Cd-accumulated maize to ruminants, 6-month-old cattle were fed with 85.82% (fresh basis) normal whole-plant maize silage diet (CON, n = 10) or Cd-accumulated whole-plant maize silage diet (CAM, n = 10) for 107 days. When compared to the CON cattle, CAM cattle showed significantly higher gain-to-feed ratio and an increased total bacterial population in the rumen, but a decreased total bacterial population in the colon. CAM cattle had higher relative abundance of Prevotella and Lachnospiraceae ND3007 group in the rumen, and Lachnospiraceae NK4A136 group and Clostridia vadinBB60 group in the colon. Notably, microbial correlations were enhanced in all segments of CAM cattle, especially Peptostreptococcaceae in the jejunum. Transcriptome analysis revealed down-regulation of several immune-related genes in the rumen of CAM cattle, and differentially expressed genes in the rumen were mostly involved in immune regulation. These findings indicated that feeding Cd-accumulated maize diet with a Cd concentration of 6.74 mg/kg dry matter (DM) could stimulate SCFA-related bacteria in the rumen, induce hormesis to promote weight gain, and improve energy utilization of cattle.
33
Gselman, Anastazija, Vilma Sem e Silva Grobelnik Mlakar. "Exposure to Cattle Slurry of Different Concentrations Influence Germination and Initial Growth of Selected Grass and Legume Species". Agriculture 13, n. 10 (15 ottobre 2023): 1999. http://dx.doi.org/10.3390/agriculture13101999.
Testo completoAbstract (sommario):
In addition to improving soil quality, the fertilisation of grassland with cattle slurry is often associated with seed dispersal. Most studies focus on the effects of cattle slurry on the germination and early development of weed species, but less is known about how slurry affects the germination process of grasses and forage legumes. The aim of Experiment I of our study was therefore to investigate the influence of soaking time in cattle slurry of different concentrations on Lolium multiflorum, Dactylis glomerata, Trifolium pratense and Trifolium repens. Seeds were soaked in undiluted (100%) and diluted cattle slurries (50% and 25%) for 14, 28, 42, 56, 70 and 84 days. Experiment II was conducted to study the initial growth of studied plants from seeds soaked in cattle slurry of different concentrations for 14 days. After the germination test, which was carried out under controlled conditions, the germination index (GI) was calculated. The results (Experiment I) show that a short soaking in cattle slurry (14 days) has no negative effect on the germination process for all species. However, a longer soaking resulted in significantly reduced and delayed germination, especially in undiluted slurry for grasses and diluted slurries for clovers. The slurry concentration (Experiment II) only influenced the root growth of L. multiflorum. Seedlings grown from seeds soaked in undiluted slurry had a 17% higher relative root length than the control and developed significantly longer root systems than the other two slurry concentrations.
34
Abdel-Ghany, A. E., e M. A. Ibrahim. "Potentials of human exposure to Listeria spp. from dairy cattle". Journal of Veterinary Medical Research 20, n. 1 (1 marzo 2010): 195–202. http://dx.doi.org/10.21608/jvmr.2020.77600.
Testo completo
35
Cheng, Qiuqiong, Lisa Perlmutter, Philip N. Smith, Scott T. McMurry, William A. Jackson e Todd A. Anderson. "A Study on Perchlorate Exposure and Absorption in Beef Cattle". Journal of Agricultural and Food Chemistry 52, n. 11 (giugno 2004): 3456–61. http://dx.doi.org/10.1021/jf049951c.
Testo completo
36
Khan, A. A., R. W. Coppock, M. M. Schuler, L. Z. Florence, L. E. Lillie e M. S. Mostrom. "Biochemical Effects of Pembina Cardium Crude Oil Exposure in Cattle". Archives of Environmental Contamination and Toxicology 30, n. 3 (1 aprile 1996): 349–55. http://dx.doi.org/10.1007/s002449900047.
Testo completo
37
Lomborg, S. R., L. R. Nielsen, P. M. H. Heegaard e S. Jacobsen. "Acute phase proteins in cattle after exposure to complex stress". Veterinary Research Communications 32, n. 7 (7 maggio 2008): 575–82. http://dx.doi.org/10.1007/s11259-008-9057-7.
Testo completo
38
Khan, Mudassar, Ashiq Mohammad, Karam Ahad, Athanasios Katsoyiannis, Salman Akbar Malik, Muhammad Abdullaha, Azhar Rashid et al. "Cattle egrets as a biosentinels of persistent organic pollutants exposure". Environmental Geochemistry and Health 36, n. 3 (13 settembre 2013): 375–84. http://dx.doi.org/10.1007/s10653-013-9556-5.
Testo completo
39
Paling, R. W., C. Mpangala, B. Luttikhuizen e G. Sibomana. "Exposure of Ankole and crossbred cattle to theileriosis in Rwanda". Tropical Animal Health and Production 23, n. 4 (dicembre 1991): 203–14. http://dx.doi.org/10.1007/bf02357101.
Testo completo
40
Khan, A. A., R. W. Coppock, M. M. Schuler, L. Z. Florence, L. E. Lillie e M. S. Mostrom. "Biochemical effects of pembina cardium crude oil exposure in cattle". Archives of Environmental Contamination and Toxicology 30, n. 3 (marzo 1996): 349–55. http://dx.doi.org/10.1007/bf00212293.
Testo completo
41
Kiiza, David, Savino Biryomumaisho, Ian D. Robertson e Jorge A. Hernandez. "Seroprevalence of and Risk Factors Associated with Exposure to Brucella Spp. in Dairy Cattle in Three Different Agroecological Zones in Rwanda". American Journal of Tropical Medicine and Hygiene 104, n. 4 (7 aprile 2021): 1241–46. http://dx.doi.org/10.4269/ajtmh.20-1426.
Testo completoAbstract (sommario):
ABSTRACTLivestock production is a key element for poverty alleviation, food security, and economic growth in Rwanda. In 2017, the national average milk production per cow was about 2.5 L per day; in 2020–2021, it is projected to increase to 3.5 L per day if improvement interventions including those designed to reduce the burden of brucellosis in cattle are implemented. The objective of the study reported here was to estimate the seroprevalence of and identify risk factors associated with dairy farms and cattle classified as seropositive to Brucella spp. in three different agroecological zones in Rwanda. Most study farms (40/85 or 47%) had one head of cattle only. Using the Rose Bengal test, the seroprevalence of brucellosis was 28/85 or 33% (95% CI = 24%, 43%) at the farm level and 63/465 or 14% (95% CI = 11%, 17%) at the animal level. Using logistic regression, at the farm level, the presence of seropositive cattle was associated with herd size (2–45 cattle, odds ratio = 21.2; 95% CI = 2.4, 184.5) (46–220 cattle, OR = 288.5; 95% CI = 24.3, 3,423.1) compared to farms with one animal, after controlling for main breed (local breeds, crossbreeds) on the farm. In addition, the odds of testing seropositive were 10.7 (95% CI = 2.3, 49.1) and 149.5 (95% CI = 19.3, 1,158.7) times higher in farms in Nyabihu district and Nyagatare district, respectively, than in farms in Muhanga district, after controlling for main breed on the farm. The odds of seropositivity to Brucella spp. were 2.8 times higher in farms with mostly local breeds, than in those with mostly crossbreeds; but the association was confounded by herd size and geographic location. At the animal level, the odds of seropositivity to Brucella spp. were 2.6 times higher in adult cattle than in young cattle (95% CI = 1.1, 6.3). Finally, we observed a high frequency of adult cattle (86%) and a high seroprevalence of brucellosis in adult cattle (25%) in Nyagatare; an indication that, in the absence of culling and other control measures, Brucella spp. infection pressure can be relatively constant and a steady source of disease transmission in pastoral systems in that district.
42
Mumford, Elizabeth L., Brian J. McCluskey, Josie L. Traub-Dargatz, Beverly J. Schmitt e M. D. Salman. "Serologic evaluation of vesicular stomatitis virus exposure in horses and cattle in 1996". Journal of the American Veterinary Medical Association 213, n. 9 (1 novembre 1998): 1265–69. http://dx.doi.org/10.2460/javma.1998.213.09.1265.
Testo completoAbstract (sommario):
Objective To determine potential risk factors for vesicular stomatitis (VS) in Colorado livestock in 1995 and evaluate VS virus (VSV) exposure of Colorado livestock in 1996. Design Retrospective case-control study of VS risk factors and seroprevalence evaluation. Sample Population Premises included 52 that had VS-positive animals and 33 that did not have VS-positive animals during the 1995 epidemic, and 8 in the vicinity of premises that had VS-positive animals during the 1995 epidemic. Procedure Layout and management data for premises were collected during site visits in 1996. Signalment and management data were collected for animals from which samples were obtained, and samples were tested by serologic examination and virus isolation. The VSV seroprevalence rate was estimated for Colorado, using serum obtained for equine infectious anemia testing and from the Market Cattle Identification program in Colorado. Results At least 1 animal was seropositive for VSV. on 35 of 52 (67%) premises, and 71 of 228 (31 %) animals tested were seropositive for VSV Seroprevalence was 63 of 170 (37%) for horses and 8 of 54 (15%) for cattle. Seroprevalence of VSV in animals from nonstudy premises in Colorado in 1996 was estimated to be 1.1% in cattle and 0.8% in horses. Clinical Implications Overall VSV seroprevalence in Colorado livestock was less than seroprevalence in epidemic areas, and seroprevalence rates in epidemic areas were greater for horses than cattle. Results may indicate that some animals had subclinical VSV infection during epidemics and that animals may be exposed to VSV between epidemics. (J Am Vet Med Assoc 1998;213:1265-1269)
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Muñoz-Solano, Borja, Elena Lizarraga Pérez e Elena González-Peñas. "Monitoring Mycotoxin Exposure in Food-Producing Animals (Cattle, Pig, Poultry, and Sheep)". Toxins 16, n. 5 (9 maggio 2024): 218. http://dx.doi.org/10.3390/toxins16050218.
Testo completoAbstract (sommario):
Food-producing animals are exposed to mycotoxins through ingestion, inhalation, or dermal contact with contaminated materials. This exposure can lead to serious consequences for animal health, affects the cost and quality of livestock production, and can even impact human health through foods of animal origin. Therefore, controlling mycotoxin exposure in animals is of utmost importance. A systematic literature search was conducted in this study to retrieve the results of monitoring exposure to mycotoxins in food-producing animals over the last five years (2019–2023), considering both external exposure (analysis of feed) and internal exposure (analysis of biomarkers in biological matrices). The most commonly used analytical technique for both approaches is LC-MS/MS due to its capability for multidetection. Several mycotoxins, especially those that are regulated (ochratoxin A, zearalenone, deoxynivalenol, aflatoxins, fumonisins, T-2, and HT-2), along with some emerging mycotoxins (sterigmatocystin, nivalenol, beauvericin, enniantins among others), were studied in 13,818 feed samples worldwide and were typically detected at low levels, although they occasionally exceeded regulatory levels. The occurrence of multiple exposure is widespread. Regarding animal biomonitoring, the primary objective of the studies retrieved was to study mycotoxin metabolism after toxin administration. Some compounds have been suggested as biomarkers of exposure in the plasma, urine, and feces of animal species such as pigs and poultry. However, further research is required, including many other mycotoxins and animal species, such as cattle and sheep.
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Wells, G. A. H., T. Konold, M. E. Arnold, A. R. Austin, S. A. C. Hawkins, M. Stack, M. M. Simmons et al. "Bovine spongiform encephalopathy: the effect of oral exposure dose on attack rate and incubation period in cattle". Journal of General Virology 88, n. 4 (1 aprile 2007): 1363–73. http://dx.doi.org/10.1099/vir.0.82421-0.
Testo completoAbstract (sommario):
The dose–response of cattle exposed to the bovine spongiform encephalopathy (BSE) agent is an important component of modelling exposure risks for animals and humans and thereby, the modulation of surveillance and control strategies for BSE. In two experiments calves were dosed orally with a range of amounts of a pool of brainstems from BSE-affected cattle. Infectivity in the pool was determined by end-point titration in mice. Recipient cattle were monitored for clinical disease and, from the incidence of pathologically confirmed cases and their incubation periods (IPs), the attack rate and IP distribution according to dose were estimated. The dose at which 50 % of cattle would be clinically affected was estimated at 0.20 g brain material used in the experiment, with 95 % confidence intervals of 0.04–1.00 g. The IP was highly variable across all dose groups and followed a log-normal distribution, with decreasing mean as dose increased. There was no evidence of a threshold dose at which the probability of infection became vanishingly small, with 1/15 (7 %) of animals affected at the lowest dose (1 mg).
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Waldner, C. L., C. S. Ribble e E. D. Janzen. "Evaluation of the impact of a natural gas leak from a pipeline on productivity of beef cattle". Journal of the American Veterinary Medical Association 212, n. 1 (1 gennaio 1998): 41–48. http://dx.doi.org/10.2460/javma.1998.212.01.41.
Testo completoAbstract (sommario):
Objective To determine the association between a leak of sour natural gas (more than 30% hydrogen sulfide) from a pipeline in a river valley and the health of beef cattle in the intensively ranched surrounding area. Design Prospective cohort study. Sample Population 13 herds of cattle within 4 km (2.5 miles) of the leak and 10 herds outside the 4-km zone. Procedure Distance of herds from the leak site was determined, using geographic information system technology. Information about speed and direction of winds was obtained from a local meteorologic station and an ambient air-quality monitoring trailer. Health and productivity data for surrounding beef herds, as well as exposure information, were collected and analyzed. Results An association was not found between total herd calf mortality and herd distance from the leak, wind-aided exposure, location in the river valley, signs of irritation consistent with exposure to the gas, or reports of odors of gas at the time of the leak. Management changes reported in response to the gas leak were identified as risk factors for total herd calf mortality. Other herd-level risk factors associated with increased calf mortality ratio included a median calving date in February and percentage of twin births for a herd. Clinical Implications In this example, we did not detect an association between productivity of cattle and exposure to sour natural gas. Several methods can be used for ranking potential exposure after discovery of a leak. (J Am Vet Med Assoc 1998;212:41–48)
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Ji, Benxiu, Chester B. Thomas e Michael T. Collins. "Evaluation of an enzyme-linked immunosorbent assay that uses the 41-kd flagellin as the antigen for detection of antibodies to Borrelia burgdorferi in cattle". American Journal of Veterinary Research 55, n. 9 (1 settembre 1994): 1213–19. http://dx.doi.org/10.2460/ajvr.1994.55.09.1213.
Testo completoAbstract (sommario):
Summary An elisa was developed to detect antibodies to the 41-kd flagellin (P41) of Borrelia burgdorferi in serum obtained from cattle. Absorption studies, immunoblot analysis, immunoelectron microscopy, and correlation of results of the P41 -elisa and the P39- elisa as well as measurement of the antibody to P41 in calves challenge-exposed with Borrelia theileri were used to assess the specificity of the P41-elisa. Antigens derived from Escherichia coli, Leptospira interrogans serovar hardjo, and B burgdorferi were used for absorption studies and immunoblot analysis. Antibodies to P41 of B burgdorferi cross-reacted with antigens of E coli, but were not cross-reactive with L hardjo. A value 3 SD higher than the mean of the negative-control population of cattle was defined as the minimum value (cutoff value) for a positive result by the P41-elisa. Use of this value for classification of test results reduced the predicted rate of false-positive results attributable to E coli cross-reactivity to 1%. Immunoblot analysis revealed that test-positive serum from cattle reacted mainly with 41-, 39-, 34-, and 31-kd proteins of B burgdorferi, as well as several smaller proteins. Immunoelectron microscopy revealed that serum from cattle that was test-positive by the P41-elisa bound to the flagellin and outer membrane of B burgdorferi. Results of absorption studies, immunoblot analysis, and immunoelectron microscopy were correlated and indicated that serum from cattle that was test-positive by P41-elisa had stronger reactivity to B burgdorferi antigens than to antigens of E coli or L hardjo. The concentrations of antibodies measured by P41-elisa and P39-elisa testing were highly correlated (R2 = 0.78). Calves challenge-exposed with B theileri also had test-positive results by the P41-elisa as early as 2 weeks after exposure, but serum antibody concentrations decreased to prechallenge-exposure concentrations by 9 weeks after exposure. We concluded that the P41- elisa was useful as a screening method to detect B burgdorferi infections in cattle.
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Rojas, Camila Santos, Carly Haimerl, Fahad Rafiq, Gabriel A. Zayas, Cristiane Gonçalves Titto e Raluca Mateescu. "PSVI-15 Impact of breed composition on hair glucocorticoid levels in beef cattle after extended heat stress". Journal of Animal Science 102, Supplement_3 (1 settembre 2024): 531–32. http://dx.doi.org/10.1093/jas/skae234.597.
Testo completoAbstract (sommario):
Abstract More than one-half of the world’s cattle are maintained in hot environments, making heat stress a significant issue for the beef industry. Around $370 million is lost annually due to reduced performance due to heat stress, which has other detrimental impacts on cattle, such as decreased feed intake, fertility, and immune response. The assessment of hair glucocorticoids (hGC) serves as a valuable tool for evaluating chronic stress levels in beef cattle. Unlike traditional cortisol measurements, which provide only a glimpse of stress at a specific moment, hGCs offer a retrospective view of long-term stress exposure. This makes them particularly valuable for assessing chronic stress, which can profoundly impact animal health, welfare, and productivity. By quantifying hGC concentrations, we gain insights into the cumulative stress experienced by cattle over time, allowing for more comprehensive monitoring and management strategies. This study investigated the relationship between hGC concentrations and breed composition in beef cattle, specifically focusing on whether breed composition influences hGC concentrations after prolonged heat exposure. Animals from the University of Florida’s Multibreed Angus-Brahman herd were used. Hair samples were collected from 240 cows during the summer of 2017 and 2018, with breed compositions ranging from 100% Brahman to 100% Angus. Starting with a 4 mg hair sample, the hGC were extracted and analyzed with the Cortisol ELISA KIT (Neogen Corporation, Ayr, UK). An Analysis of Variance (ANOVA) was conducted to examine the relationship between hGC concentration, breed composition, and batch effect. The results indicated a significant effect of breed composition on hGC concentration (P-value 0.01406). These findings suggest that breed composition influences chronic stress during prolonged periods of heat exposure. However, individual factors like thermotolerance, health status, and social stress may also have a role in chronic stress levels. To better understand these factors, future steps will involve comparing the hGC concentration results between thermotolerant and non-thermotolerant animals. This comparison will provide insights into the potential differences in stress responses between cattle breeds adapted to hot environments and those less tolerant to heat stress.
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Corman, Victor Max, Adam Grundhoff, Christine Baechlein, Nicole Fischer, Anatoly Gmyl, Robert Wollny, Dickson Dei et al. "Highly Divergent Hepaciviruses from African Cattle". Journal of Virology 89, n. 11 (18 marzo 2015): 5876–82. http://dx.doi.org/10.1128/jvi.00393-15.
Testo completoAbstract (sommario):
ABSTRACTThe hepatitis C virus (HCV; genusHepacivirus) is a highly relevant human pathogen. Unique hepaciviruses (HV) were discovered recently in animal hosts. The direct ancestor of HCV has not been found, but the genetically most closely related animal HVs exist in horses. To investigate whether other peridomestic animals also carry HVs, we analyzed sera from Ghanaian cattle for HVs by reverse transcription-PCR (RT-PCR). Nine of 106 specimens from different sampling sites contained HV RNA (8.5%) at median viral loads of 1.6 × 105copies/ml. Infection seemed unrelated to cattle age and gender. Near-full-genome sequencing of five representative viruses confirmed taxonomic classifications. Cattle HVs formed two distinct phylogenetic lineages that differed by up to 17.7% on the nucleotide level in the polyprotein-encoding region, suggesting cocirculation of different virus subtypes. A conserved microRNA122-binding site in the 5′ internal ribosomal entry site suggested liver tropism of cattle HVs. Phylogenetic analyses suggested the circulation of HVs in cattle for several centuries. Cattle HVs were genetically highly divergent from all other HVs, including HCV. HVs from genetically related equine and bovine hosts were not monophyletic, corroborating host shifts during the evolution of the genusHepacivirus. Similar to equine HVs, the genetic diversity of cattle HVs was low compared to that of HCV genotypes. This suggests an influence of the human-modified ecology of peridomestic animals on virus diversity. Further studies should investigate the occurrence of cattle HVs in other geographic areas and breeds, virus pathogenicity in cattle, and the potential exposure of human risk groups, such as farmers, butchers, and abattoir workers.IMPORTANCEHCV (genusHepacivirus) is a major human pathogen, causing liver failure and cancer. Unique hepaciviruses (HVs) were discovered over the last few years in animals, but the direct ancestor of HCV has not been found. The animal HV most closely related to HCV so far originated from horses, suggesting that other livestock animals also harbor HVs. Therefore, we investigated African cattle and discovered previously unknown HVs at high prevalence and viral loads. Because of the agricultural importance of cattle, it may be relevant to investigate HV pathogenicity. The frequent exposure of humans to cattle also may warrant investigations of the zoonotic potential of these viruses. Evolutionary analyses suggested that cattle HVs have existed for centuries. Despite the genetic relatedness of their animal hosts, HVs from cattle and horses were not phylogenetically related, corroborating frequent host shifts during the evolution of the genusHepacivirus.
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Semu, S. M., T. F. Peter, D. Mukwedeya, A. F. Barbet, F. Jongejan e S. M. Mahan. "Antibody Responses to MAP 1B and Other Cowdria ruminantium Antigens Are Down Regulated in Cattle Challenged with Tick-Transmitted Heartwater". Clinical Diagnostic Laboratory Immunology 8, n. 2 (1 marzo 2001): 388–96. http://dx.doi.org/10.1128/cdli.8.2.388-396.2001.
Testo completoAbstract (sommario):
ABSTRACT Serological diagnosis of heartwater or Cowdria ruminantium infection has been hampered by severe cross-reactions with antibody responses to related ehrlichial agents. A MAP 1B indirect enzyme-linked immunosorbent assay that has an improved specificity and sensitivity for detection of immunoglobulin G (IgG) antibodies has been developed to overcome this constraint (A. H. M. van Vliet, B. A. M. Van der Zeijst, E. Camus, S. M. Mahan, D. Martinez, and F. Jongejan, J. Clin. Microbiol. 33:2405–2410, 1995). When sera were tested from cattle in areas of endemic heartwater infection in Zimbabwe, only 33% of the samples tested positive in this assay despite a high infection pressure (S. M. Mahan, S. M. Samu, T. F. Peter, and F. Jongejan, Ann. N.Y. Acad. Sci 849:85–87, 1998). To determine underlying causes for this observation, the kinetics of MAP 1B-specific IgG antibodies in cattle after tick-transmitted C. ruminantium infection and following recovery were investigated. Sera collected weekly over a period of 52 weeks from 37 cattle, which were naturally or experimentally infected with C. ruminantium via Amblyomma hebraeum ticks, were analyzed. MAP 1B-specific IgG antibody responses developed with similar kinetics in both field- and laboratory-infected cattle. IgG levels peaked at 4 to 9 weeks after tick infestation and declined to baseline levels between 14 and 33 weeks, despite repeated exposure to infected ticks and the establishment of a carrier state as demonstrated by PCR and xenodiagnosis. Some of the serum samples from laboratory, and field-infected cattle were also analyzed by immunoblotting and an indirect fluorescent-antibody test (IFAT) to determine whether this observed seroreversion was specific to the MAP 1B antigen. Reciprocal IFAT and immunoblot MAP 1-specific antibody titres peaked at 5 to 9 weeks after tick infestation but also declined between 30 and 45 weeks. This suggests that MAP 1B-specific IgG antibody responses and antibody responses to other C. ruminantium antigens are down regulated in cattle despite repeated exposure to C. ruminantium via ticks. Significantly, serological responses to the MAP 1B antigen may not be a reliable indicator of C. ruminantium exposure in cattle in areas of endemic heartwater infection.
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Djangwani, J., GO Abong’, LG Njue e DWM Kaindi. "Risk factors of exposure to Brucella through milk consumption in cattle keeping households in Rwanda". African Journal of Food, Agriculture, Nutrition and Development 24, n. 7 (27 luglio 2027): 26899–920. http://dx.doi.org/10.18697/ajfand.132.22880.
Testo completoAbstract (sommario):
Milk produced in Rwanda and consumed in cattle keeping households poses undocumented food safety risks including the transmission of the zoonotic brucellosis from animals to humans. The aim of this study was, therefore, to determine the risk factors of exposure to Brucella species through milk consumption in zero grazing and open grazing cattle keeping households in Rwanda. The study was a cross-sectional study which involved 198 and 132 households practicing zero grazing and open grazing cattle production systems, respectively. To determine the risk factors exposure to Brucella through milk consumption, a questionnaire was used to collect data on milk consumption habits and indirect Enzyme-Linked Immuno-Sorbent Assay (i-ELISA) was used to collect data on farm bulk milk contamination with Brucella. Collected questionnaire and i-ELISA data were then analyzed using SPSS descriptive statistics and logistic regression. In nearly half (49.1 %; 162/330) of all surveyed households, raw milk was consumed. And overall, 14.2% (47/330) of all surveyed households were exposed to Brucella by having at least one household member consuming raw milk in a household for which the farm bulk milk sample tested positive for Brucella. The proportion of open grazing households in which raw milk was consumed and from which the farm bulk milk sample tested positive for Brucella (34.8 %; 46/132) was significantly high (p < 0.05) compared to the proportion of zero grazing households consuming raw milk and having a Brucella positive farm bulk milk sample (0.5 %; 1/198). While in total 4.8 % (77/1589) of all surveyed individual household members were exposed to Brucella by consuming raw milk in a household for which the farm bulk milk sample had tested positive for Brucella, the cattle keeper was the most exposed household member (OR=50.82, 95 % CI [17.9-143.9], p < 0.05). Practicing open grazing cattle production system was significantly associated with raw milk consumption and raw milk consumption in a household with a Brucella positive farm bulk milk. There is a risk of exposure to Brucella through milk consumption especially in households practicing open grazing cattle production in Rwanda. Educational campaigns are needed to raise awareness about the dangers of drinking raw milk in regards to zoonotic brucellosis. Key words: Brucella, consumption, exposure, grazing, household, milk, risk factor, Brucella positive