Neurological diseases of ruminant livestock in Australia. III: bacterial and protozoal infections

Bacteria (including chlamydia) and protozoa can produce neurological disease in Australian ruminant livestock and the nature of the inflammatory and neuroparenchymal response is often suggestive of a particular aetiological agent. An overview of the clinicopathological features of infectious disease affecting the central nervous system (CNS) is followed by a discussion of important bacterial and protozoal infections in Australia. Each infectious disease is discussed in terms of classification and pathogenesis linked to clinical signs and gross and microscopic findings. The literature review is restricted to infectious conditions causing CNS disease in Australia. Sources include the Australian Veterinary Journal (over 50 years of articles), the quarterly newsletter of the National Animal Health Surveillance System and the Animal Health Surveillance Quarterly.     

Musculoskeletal disorders and psychosocial risk factors among veterinarians in Queensland, Australia

Objective   Although musculoskeletal disorders (MSD) represent one of the most important occupational health issues in contemporary society, few studies have specifically investigated this problem among veterinarians.
Design   An anonymous questionnaire survey mailed to all veterinarians registered with the Veterinary Surgeons Board of Queensland during 2006.
Results   Almost two-thirds of respondents (63%) had experienced MSD of the lower back, 57% had experienced neck-related MSD, 52% had experienced shoulder-related MSD and 34% had experienced MSD of the upper back during the previous 12 months. MSD was statistically correlated with a range of psychosocial factors, including stress associated with career structure, time pressures, client's attitude, lack of recognition by the public, lack of recognition by colleagues, lack of understanding from family or partners and work stress because of insufficient holidays each year.
Conclusion   Overall, this study has demonstrated significant correlations between MSD and psychosocial risk factors among a large cohort of veterinarians, apparently for the first time in the published literature. The results also suggest that personal and workplace issues may contribute more to the development of MSD among veterinarians than many of the previously recognised ergonomic risk factors.     

Chondrodysplasia in Australian Dexter cattle

Objective To describe the occurrence of chondrodysplasia in Australian Dexter cattle.
Design A pathological and genetic case report.
Procedure Congenital lethal chondrodysplasia was studied in two female Dexter foetuses aborted mid to late gestation. Clinicopathological findings including histological changes in limb bones, and analysis of pedigree information were evaluated.
Results Characteristic features of congenital lethal chon-drodysplasia (Dexter bulldog) include abortion, disproportionate dwarfism, a short vertebral column, marked micromelia, a relatively large head with retruded muzzle, cleft palate and protruding tongue and a large abdominal hernia. Histological changes in limb bones are consistent with failure of endochondral ossification. Dexter chondrodysplasia is considered to be inherited in an incompletely dominant manner with the homozygous form producing the congenital lethal condition. A preliminary minimum estimate of heterozy-gote frequency is 19% within the registered Australian Dexter herd, based on analysis of the contribution of three obligate heterozygotes whose semen has been widely used by artificial insemination in Australia.
Conclusion Dexter chondrodysplasia is present in Australian cattle and further cases of the homozygous form, congenital lethal chondrodysplasia, are likely to occur.
Recommendation It is requested that spleen and liver tissue from bulldog foetuses and blood from their parents be collected to assist research into Dexter chondrodysplasia.     

The effect of breed and sex on sulfamethazine,enrofloxacin, fenbendazole and flunixin meglumine pharmacokinetic parameters in swine

Drug use in livestock has received increased attention due to welfare concerns and food safety. Characterizing heterogeneity in the way swine populations respond to drugs could allow for group‐specific dose or drug recommendations. Our objective was to determine whether drug clearance differs across genetic backgrounds and sex for sulfamethazine, enrofloxacin, fenbendazole and flunixin meglumine. Two sires from each of four breeds were mated to a common sow population. The nursery pigs generated (n = 114) were utilized in a random crossover design. Drugs were administered intravenously and blood collected a minimum of 10 times over 48 h. A non‐compartmental analysis of drug and metabolite plasma concentration vs. time profiles was performed. Within‐drug and metabolite analysis of pharmacokinetic parameters included fixed effects of drug administration date, sex and breed of sire. Breed differences existed for flunixin meglumine (P‐value<0.05; Cl, Vd_ss) and oxfendazole (P‐value<0.05, AUC_0→∞). Sex differences existed for oxfendazole (P‐value < 0.05; T_max) and sulfamethazine (P‐value < 0.05, Cl). Differences in drug clearance were seen, and future work will determine the degree of additive genetic variation utilizing a larger population.     

Gait abnormalities and ridden horse behaviour in a convenience sample of the United Kingdom ridden sports horse and leisure horse population

The objectives of this study were to compare horses’ gaits in hand and when ridden; to assess static and dynamic saddle fit for each horse and rider; to apply the Ridden Horse Pain Ethogram (RHpE) and relate the findings to gait abnormalities consistent with musculoskeletal pain, rider position and balance and saddle fit; and to document noseband use and its relationship with mouth opening during ridden exercise. Data were acquired prospectively from a convenience sample of horses believed by their owners to be working comfortably. All assessments were subjective. Gait in hand and when ridden were evaluated independently, by two assessors, and compared using McNemar’s test. Static tack fit and noseband type were recorded. Movement of the saddle during ridden exercise, rider position, balance and size relative to the saddle was documented. RHpE scores were based on assessment of video recordings. Multivariable Poisson regression analysis was used to determine factors which influenced the RHpE scores. Of 148 horses, 28.4% were lame in hand, whereas 62.2% were lame ridden (P<0.001). Sixty per cent of horses showed gait abnormalities in canter. The median RHpE score was 8/24 (interquartile range 5, 9; range 0, 15). There was a positive association between lameness and the RHpE score (P<0.001). Riding School horses had higher RHpE scores compared with General Purpose horses (P = 0.001). Saddles with tight tree points (P = 0.001) and riders seated at the back of the saddle rather than the middle (P = 0.001) were associated with higher RHpE scores. Horses wearing crank cavesson compared with cavesson nosebands had higher RHpE scores (P = 0.006). There was no difference in mouth opening, as defined by the RHpE, in horses with a noseband with the potential to restrict mouth opening, compared with a correctly fitted cavesson noseband, or no noseband. It was concluded that lameness or gait abnormalities in canter may be missed unless horses are assessed ridden.