Veterinary Record Open最新文献

Background: Avian influenza viruses are still causing major concern not only to the poultry industry but also to human health across the globe. The live poultry markets and the small-scale local breeding of various species of birds in backyards are still playing important roles in the sustainability of most virulent influenza viruses, especially H5N8.

Methods: The authors investigated an outbreak of highly pathogenic avian influenza H5N8 in backyard flocks in Al Ahsa, Eastern Saudi Arabia that occurred in 2017-2018.

Results: A range of poultry including chickens, ostriches, ducks, pigeons and turkeys were clinically affected. Phylogenetic analysis suggested that this was a common source outbreak caused by a virus closely related to H5N8 viruses causing outbreaks elsewhere in Saudi Arabia in early 2018.

Conclusions: Small backyard flocks are still contributing to the epidemiology and transmission of H5N8.

Background: Rabbits are the third most popular pet in the UK, but little research into their welfare needs has been conducted.

Methods: A modified Delphi method was used to generate expert consensus on the most important welfare issues for rabbits in the UK. The study involved 11 experts, recruited from a range of disciplines. The experts generated an initial broad list of welfare issues via an online discussion board. Two rounds of online surveys were conducted to prioritise these issues. The final round was a workshop with a subsection of experts. The experts decided that welfare issues should be ranked considering: (1) severity, (2) duration, and (3) prevalence.

Results: Experts considered that rabbits were often kept in inadequate housing, were not handled or socialised properly, were fed inappropriate diets and owners failed to vaccinate their rabbits against preventable diseases. Rabbits were thought to experience a reduced life expectancy. Lack of owner knowledge of rabbit husbandry and behaviour and, in some cases, also lack of veterinary knowledge, contributed to poor rabbit welfare.

Conclusions: The Delphi process resulted in consensus on the most significant welfare challenges faced by rabbits and can help guide future research and education priority decisions.

Background: Escherichia coli is an important aetiological agent of bovine mastitis worldwide.

Methods: In this study, 82 E. coli from bovine mastitis milk samples from 49 farms were analysed for their genetic diversity using phylogenetic grouping and multilocus sequence typing. The isolates were examined by PCR for a selection of virulence factors (VFs). Antimicrobial susceptibility profiles were assessed using the disk diffusion method.

Results: The most prevalent phylogroups were group B1 (41.5 per cent of the isolates) and group A (30.5 per cent). A variety of 35 different sequence types (STs) were identified, including ST1125 (11 per cent), ST58 (9.8 per cent), ST10 (8.5 per cent) and ST88 (7.3 per cent). Aggregate VF scores (the number of unique VFs detected for each isolate) ranged from 1 to 3 for 63.4 per cent of the isolates and were at least 4 for 12.2 per cent. For 24.4 per cent of the isolates, the score was 0. The three most frequent VFs were traT, fyuA and iutA. The majority (72 per cent) of the isolates harboured traT. The majority (68.3 per cent) of the isolates were fully susceptible to all antimicrobials tested, with 22 per cent resistant to ampicillin and 14.6 per cent to tetracycline. Resistance rates were low for gentamicin (3.7 per cent), amoxicillin/clavulanic acid (2.4 per cent) and ceftiofur (1.2 per cent), respectively.

Conclusion: Among the study's sample population, E. coli strains were genotypically diverse, even in cows from the same farm, although some STs occurred more frequently than others. Susceptibility to clinically relevant compounds remained high.

Background: Urinary calcium excretion by rabbits is set proportionately higher than that of other species, giving the rabbit urine its characteristic cloudy appearance. During pregnancy, lactation and growth, or when metabolic disorders interfere in the renal excretion of calcium, it is reported that less calcium is excreted and the urine appears clear. The quantification of the calcium concentration in the urine of rabbits may be of importance in the management of diseases that affect calcium metabolism, especially in kidney disease; however, reference intervals for urinary calcium concentration (UC) are unreported in pet rabbits.

Methods: Prospective data from 63 healthy pet rabbits were evaluated. An inhouse modified Arsenazo III technique, without acidifying the urine, was used to determine the reference intervals for UC and UC:creatinine ratio. Urinary protein:creatinine ratio, UC, UC:creatinine ratio, urinary gamma-glutamyl transferase concentration (UG), UG:creatinine ratio, phosphorus, plasma total calcium, plasma creatinine, urea and ionised calcium were assessed according to age, sex, neutered status, urine collection method and Encephalitozoon cuniculi IgG status in healthy rabbits.

Results: The reference intervals for UC and UC:creatinine ratio were 4.2-31.1 mg/dl (1.03-7.78 mmol/l) and less than 0.3, respectively. The results showed that none of these variables was influenced by the parameters evaluated, except for the phosphorus value, which was higher in pet rabbits aged up to 3 years compared with those over 3 years, suggesting that published reference values for plasma phosphorus in rabbits should be adjusted according to age.

Conclusion: The modified Arsenazo III technique described in the present work and the established reference values for UC and UCC in pet rabbits could be useful in the management of kidney disease in rabbits. The results showed that E cuniculi IgG seropositivity has no influence on the variables of renal interest in otherwise healthy rabbits.

Background: The objectives of this study were to investigate the impact of pain mitigation at birth to assisted beef calves and determine the risk factors associated with transfer of passive immunity (TPI), health, and growth.

Methods: Two hundred and thirty cow-calf pairs requiring calving assistance were enrolled. Calves were randomised to receive meloxicam (0.5 mg/kg) or an equivalent volume of placebo subcutaneously at birth. Calf blood samples were collected between one and seven days of age to determine serum immunoglobulin (IgG) concentration. Colostrum intake, treatment for disease, mortality, and weaning weights were recorded. Multilevel linear or logistic regression models were used to determine the effects of meloxicam and to identify risk factors.

Results: There was no effect of meloxicam on serum IgG concentrations, average daily gain (ADG), or risk of inadequate TPI (serum IgG concentration <24 g/l), treatment for disease, or mortality (P>0.05). Bottle or tube feeding calves were associated with decreased serum IgG concentrations (P=0.01) compared with nursing. Calves with an incomplete tongue withdrawal reflex had higher odds of being treated for disease compared with those with complete withdrawal (P=0.009). Being born meconium-stained and having decreased serum IgG concentrations were associated with an increased risk of mortality (P=0.03). Being born of a mature cow, having a higher birth weight, and increased serum IgG concentrations were associated with greater ADG to weaning (P<0.05).

Conclusion: Vigour assessment at birth along with good colostrum management may be important to improve TPI and health in high-risk calves such as those assisted at birth.

Background: Pigs are frequently colonised with Salmonella enterica, and this constitutes a major risk for human salmonellosis. The infection can be assessed by the serological response of pigs to S enterica. A longitudinal study was undertaken on-farm to correctly describe this serological response and investigate factors associated with age at Salmonella seroconversion.

Methods: Three pig farms and in each farm three successive batches were considered. Per batch, 40 piglets were selected at random from 10 sows (four piglets per sow). Blood was sampled from sows one week after farrowing and from piglets at weeks 1, 6, 10, 14, 18 and 22 and at the slaughterhouse. Salmonella antibodies were detected in serum using a commercial ELISA test. Factors related to farm characteristics, batch management system, porcine reproductive and respiratory syndrome infection, and sows' Salmonella serological status were recorded to assess their effect on age at seroconversion.

Results: At week 1 after farrowing, 96.5 per cent of the sows had antibodies against Salmonella. The serological results of piglets at weeks 1 and 6 only were positively correlated with those of the sows. The average age at Salmonella seroconversion was 137±2.2 days (confidence interval at 95 per cent). The first seroconversions occurred from weeks 10 to 14, but most of the pigs (54.6 per cent) were seropositive at the end of the fattening period, with variations between farms and batches (28.9-75.7 per cent). Herd/farm was significantly associated with age at seroconversion.

Conclusion: This longitudinal study allowed the authors to follow precisely the evolution of Salmonella seroconversion from maternity to slaughterhouse and confirm the relationship between the seroconversion of sows and serology of their piglets. Moreover, factors related to farm practices and management as a whole are more influential than individual factors (at the pig level) on age at Salmonella seroconversion.

Highly pathogenic avian influenza (HPAI) outbreaks engender a severe economic impact on the poultry industry and public health. Migratory waterfowl are considered the natural hosts of HPAI virus, and HPAI viruses are known to be transmitted over long distances during seasonal bird migration. Bird migration is greatly affected by the weather. Many studies have shown the relationship between either autumn or spring bird migration and climate. However, few studies have shown the relationship between annual bird migration and annual weather. This study aimed to establish a model for the number of migratory waterfowl involved in HPAI virus transmission based on meteorological data. From 136 species of waterfowl that were observed at Futatsudate in Miyazaki, Japan, from 2008 to 2016, we selected potential high-risk species that could introduce the HPAI virus into Miyazaki and defined them as 'risky birds'. We also performed cluster analysis to select meteorological factors. We then analysed the meteorological data and the total number of risky birds using a generalised linear mixed model. We selected 10 species as risky birds: Mallard (Anas platyrhynchos), Northern pintail (Anas acuta), Eurasian wigeon (Anas penelope), Eurasian teal (Anas crecca), Common pochard (Aythya ferina), Eurasian coot (Fulica atra), Northern shoveler (Anas clypeata), Common shelduck (Tadorna tadorna), Tufted duck (Aythya fuligula) and Herring gull (Larus argentatus). We succeeded in clustering 35 meteorological factors into four clusters and identified three meteorological factors associated with their migration: (1) the average daily maximum temperature; (2) the mean value of global solar radiation and (3) the maximum daily precipitation. We thus demonstrated the relationship between the number of risky birds and meteorological data. The dynamics of migratory waterfowl was relevant to the risk of an HPAI outbreak, and our data could contribute to cost and time savings in strengthening preventive measures against epidemics.