3,421 research outputs found
A four year longitudinal sero-epidemiology study of Neospora caninum in adult cattle from 114 cattle herds in south west England : associations with age, herd and dam-offspring pairs
No full textBackground: Neosporosis caused by the protozoan parasite Neospora caninum, is an economically
important cause of abortion, stillbirth, low milk yield, reduced weight gain and premature culling in
cattle. Consequently, a seroepidemiological study of N. caninum antibodies was conducted in
England with 29,782 samples of blood taken from 15,736 cattle from 114 herds visited on three
occasions at yearly intervals. Herds were categorised into lower (< 10%) and higher (≥ 10%)
median herd seroprevalence. Hierarchical models were run to investigate associations between the
sample to positive (S/P) ratio and herd and cattle factors.
Results: Ninety-four percent of herds had at least one seropositive cow; 12.9% of adult cattle had
at least one seropositive test. Approximately 90% of herds were seropositive at all visits; 9 herds
(8%) changed serological status between visits. The median N. caninum seroprevalence in positive
herds was 10% (range 0.4% to 58.8%). There was a positive association between the serostatus of
offspring and dams that were ever seropositive. In the hierarchical model of low seroprevalence
herds there was no significant association between S/P ratio and cattle age. There was a significantly
lower S/P ratio in cattle in herds that were totally restocked after the foot-and-mouth epidemic of
2001 compared with those from continuously stocked herds and cattle purchased into these herds
had a higher S/P ratio than homebred cattle. In the model of high seroprevalence herds the S/P ratio
increased with cattle age, but was not associated with restocking or cattle origin.
Conclusion: There were no strong temporal changes in herd seroprevalence of N. caninum but
90% of herds had some seropositive cattle over this time period. Vertical transmission from
seropositive dams appeared to occur in all herds. In herds with a high seroprevalence the increasing
S/P ratio in 2–4 year old cattle is suggestive of exposure to N. caninum: horizontal transmission
between adult cattle, infection from a local source or recrudescence and abortions. Between-herd
movements of infected cattle enhance the spread of N. caninum, particularly into low
seroprevalence herds. Some restocked herds had little exposure to N. caninum, while in others
infection had spread in the time since restocking
Lead exposure and source attribution for a mammalian scavenger before and after a culling program
No full textLead-based ammunition is a significant source of environmental lead and threatens species that scavenge lead-shot carcasses, particularly in areas with intensive shooting. With the impacts of lead on avian scavengers well established, there is increasing focus on the effects of lead on mammalian scavengers. We investigated lead exposure in a morphologically specialized mammalian scavenger, the Tasmanian devil (Sarcophilus harrisii), by analyzing their blood lead levels (BLLs) before and after a marsupial culling program using linear mixed effects models. We compared lead isotope signatures in devil blood to those in the culling ammunition to inform potential source attributions. We sampled 23 devils before culling and 15 after culling, finding no significant difference in mean BLLs pre and post-culling. However, devils captured closer to forestry coupes where culling had occurred had higher BLLs, and a greater proportion of devils displayed elevated BLLs post-culling (33 % compared to 18 % pre-culling). The highest BLL (7.93 μg/dL) was found in a devil post-culling and this individual had lead isotope signatures that matched the ammunition samples analyzed, suggesting the individual was exposed to lead from scavenging on culled carcasses. While 18 % of the devil blood lead samples had isotope signatures consistent with the ammunition samples, most were measurably different, indicating other sources of lead in the landscape. BLLs in our study landscape were similar to published BLLs for wild devils across Tasmania. That said, lead isotope signatures in the blood of individual devils sampled both before and after culling shifted closer to those of ammunition samples post-culling. Our results indicate that while some individual devils may have been exposed to lead from culling, most devils in the landscape did not show evidence of recent exposure. However, even low lead levels can adversely impact wildlife health and immunity, a particular concern for devils, a species endangered by disease
A Before-After Control-Impact experiment reveals that culling reduces the impacts of invasive deer on endangered peatlands
No full textInvasive deer have undesirable impacts on native ecosystems. Culling is commonly used to reduce those impacts, but is expensive and sometimes controversial. It is therefore important to robustly assess how culling reduces the impacts of invasive deer. We conducted a Before-After Control-Impact (BACI) experiment to determine how culling affects the impacts of invasive sambar deer Cervus unicolor in an endangered alpine peatland ecosystem in south-eastern Australia. We established two blocks, each with four 4300-ha experimental units, in which two units were randomly assigned to a treatment of deer culling and the other two were non-treatment areas. Sambar deer relative abundance (faecal pellet count) and three impacts (ground degradation, pugging intensity and water turbidity) in three peatland features (peatlands, natural pools and sambar deer wallows) were surveyed before and after culling was implemented. We used four metrics to quantify the culling intensity in each treatment unit: treatment versus non-treatment, number of deer culled on each unit, deer culled within a 500-m buffer of impact monitoring sites and local probability of use by the cullers (1-ha grid). The effects of culling on deer abundance and impacts were estimated using Bayesian generalised linear mixed models. Our analysis revealed that the effect of culling differed between the two experimental blocks. In one block, culling reduced deer abundance and three impacts. In the other block, culling did not reduce deer abundance but reduced three impacts and increased two impacts. The effects of culling were generally stronger when culling was estimated using finer-scale (500-m) than coarser-scale (experimental unit) culling metrics. Synthesis and applications. Our study provides experimental evidence that culling invasive sambar deer reduces some of their undesirable impacts on endangered peatlands. That not all impacts were reduced by culling suggests that some effects of invasive species are slow to recover or require higher culling intensities to be reversed
Considering animals : moral convictions concerning animals and judgement on the culling of healthy animals in animal disease epidemics
No full textAspects of bovine caesarean section associated with calf mortality, dam survival and subsequent fertility.
No full textBovine caesarean section is a common surgery performed by cattle practitioners yet evidence for justifying many aspects of the surgical procedure is lacking. Between 2001 and 2007, questionnaires were used to gather information on 103 cases of caesarean section performed in one, predominantly dairy, veterinary practice. The results showed that the 14-day cow survival rate was 80.6%, and of those surviving beyond this period, 55.4% carried another calf to term, 27.7% were culled due to infertility and 16.9% were culled due to other reasons. Variables associated with reduced 14-day dam mortality included exteriorising the uterus during surgery (odds ratio [OR] 0.018, 95% confidence interval [CI] 0.0019-0.17, P<0.001), dystocia where fetomaternal disproportion was present (OR 0.090, 95% CI 0.097-0.83, P=0.033), a female calf (OR 0.036, 95% CI 0.0019-0.69, P=0.027), no retained fetal membranes at the first post-operative revisit (OR 0.095, 95% CI 0.013-0.69, P=0.020) and removing abdominal blood clots during surgery (OR 0.10, 95% CI 0.011-0.93, P=0.043). Using a Utrecht suture pattern on the uterus was associated with reduced culling due to infertility (OR 0.12, 95% CI 0.020-0.67, P=0.016). Incision infection was noted in 25.9% of cases where incision status was recorded but this was not associated with the type of local anaesthesia used. Overall calf survival up to the first post-operative visit (24-48 h) was 59.4%, and was associated with shorter duration of surgery, and dystocia due to fetomaternal disproportion. These results offer some evidence-based guidelines to optimise outcomes for this common surgery performed under field conditions
On the AJ Conjecture for Knots
No full textWe confirm the AJ conjecture [Ga2] that relates the A-polynomial and the colored Jones polynomial for hyperbolic knots satisfying certain conditions. In particular, we show that the conjecture holds true for some classes of two-bridge knots and pretzel knots. This extends the result of the first author in [Le2], who established the AJ conjecture for a large class of two-bridge knots, including all twist knots. Along the way, we explicitly calculate the universal SL₂(C)-character ring of the knot group of the (−2, 3, 2n + 1)-pretzel knot, and show it is reduced for all integers n
Risk factors for bovine Tuberculosis at the national level in Great Britain
No full text<p><b>Background:</b> The continuing expansion of high incidence areas of bovine Tuberculosis (bTB) in Great Britain (GB) raises a number of questions concerning the determinants of infection at the herd level that are driving spread of the disease. Here, we develop risk factor models to quantify the importance of herd sizes, cattle imports from Ireland, history of bTB, badgers and cattle restocking in determining bTB incidence. We compare the significance of these different risk factors in high and low incidence areas (as determined by parish testing intervals).</p>
<p><b>Results:</b> Large herds and fattening herds are more likely to breakdown in all areas. In areas with lower perceived risk (longer testing intervals), the risk of breaking down is largely determined by the number of animals that a herd buys in from high incidence areas. In contrast, in higher perceived risk areas (shorter testing intervals), the risk of breakdown is defined by the history of disease and the probability of badger occurrence. Despite differences in the management of bTB across different countries of GB (England, Wales and Scotland), we found no significant differences in bTB risk at the national level after these other factors had been taken into account.</p>
<p><b>Conclusions:</b> This paper demonstrates that different types of farm are at risk of breakdown and that the most important risk factors vary according to bTB incidence in an area. The results suggest that significant gains in bTB control could be made by targeting herds in low incidence areas that import the greatest number of cattle from high incidence areas.</p>
Discovery of a single faint AGN in a large sample of z > 5 Lyman break galaxies
No full textAs part of a large spectroscopic survey of z > 5 Lyman break galaxies (LBGs), we have identified a single source which is clearly hosting an active galactic nucleus (AGN). Out of a sample of more than 50 spectroscopically confirmed R-band dropout galaxies at z∼ 5 and above, only J104048.6−115550.2 at z= 5.44 shows evidence for a high ionization potential emission line indicating the presence of a hard ionizing continuum from an AGN. Like most objects in our sample the rest-frame-UV spectrum shows the UV continuum breaking across a Lyα line. Uniquely within this sample of LBGs, emission from N V is also detected, a clear signature of AGN photoionization. The object is spatially resolved in Hubble Space Telescope (HST) imaging. This, and the comparatively high Lyα/N V flux ratio indicates that the majority of the Lyα (and the UV continuum longward of it) originates from stellar photoionization, a product of the ongoing starburst in the LBG. Even without the AGN emission, this object would have been photometrically selected and spectroscopically confirmed as a Lyman break in our survey. The measured optical flux (IAB= 26.1) is therefore an upper limit to that from the AGN and is of order 100 times fainter than the majority of known quasars at these redshifts. The detection of a single object in our survey volume is consistent with the best current models of high redshift AGN luminosity function, providing a substantial fraction of such AGN is found within luminous starbursting galaxies. We discuss the cosmological implications of this discovery
Tytärten karsiintumisen merkityksestä sonnien jälkeläisryhmissä
No full textvokKirjasto Aj-kOn the significance of the culling og daughtters in the progeny group of bull
The author, the text, and the (post)critic: notes on the encounter between postcritique and postcolonial criticism
No full textThe article confronts postcolonial criticism with postcritique, a proposal by Rita Felski for a hermeneutic strategy aiming to overcome the limits of critique. Because of its self-reflexivity, its liaison with poststructuralism, and the societal categories it mobilizes, postcritics often see postcolonial criticism as a quintessential example of critique. However, postcolonial authors share similar concerns as postcritics, particularly when warning against any hasty conflation between intellectual work and political commitment. This article argues that the postcritical understanding of critique eschews the connection between critique and the realm of culture, thereby running the risk of doing away with context altogether. In order to account for the frameworks or contexts in which cultural objects are produced, without falling into some of the pitfalls of critique that postcritique aims to counter, the article proposes to look at the figure of the author as a bridge between the individual and the collective, as Edward Said suggests. The article closes with an analysis of several (critical and postcritical) readings of J. M. Coetzee’s The Childhood of Jesus to provide an example of how authorship can enter the interpretive scene through the figure of ‘late style’
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