Environmental and behavioural factors affecting the prevalence of foot lameness in New Zealand dairy herds - a case-control study

A case-control study of environmental and behavioural factors influencing foot lameness was undertaken on 62 dairy herds comprising an average of 185 milking cows in Taranaki, New Zealand. Thirty two case herds were identified as having had at least 10 per cent of the cows lame during the milking season in which the herd was studied, and thirty control herds were selected on the basis that no more than 3 per cent of cows in these herds had been lame per year for at least two years immediately prior to investigation. Each herd was visited at both a morning and an afternoon milking, and 58 risk factors were measured between the time the farmer began to assemble the cows for milking and the completion of milking. Comparison of single variables between case and control herds identified 24 which showed differences (p<0.10). These variables were then subjected to stepwise multivariate logistic regression, and statistically significant variables in this analysis were used to create a tentative path diagram of possible causal web relationships between the various risk factors and the outcome variable, the lameness prevalence level. Information from a review of the published literature was used to include further variables to the 24 into the initial (or null hypothesis) path model. Logistic path analysis was then used to eliminate non-significant paths from the diagram, leaving 19 arrows joining 13 variables in the final path diagram, compared with 33 joining 20 variables in the initial version. The most influential variables in explaining variation between case and control herds were the average level of maintenance of the track and the degree of patience shown by the farmer in bringing the cows in for milking. Overall, factors associated with the movement of animals to the milking shed explained 40 per cent of the variation (deviance) with regard to the lameness prevalence level. Risk factors associated with characteristics of the milking process explain 24 per cent, and risk factors associated with characteristics of the cows in the herd explain 9.5 per cent. Recommendations are made on management changes which deserve further investigation as ways of reducing lameness problems in dairy herds.     

Flow Cytometry Identification of X- and Y-Chromosome-Bearing Goat Spermatozoa

Flow cytometric sorting technology was used to measure the difference in DNA content between X- and Y-chromosome-bearing spermatozoa in bucks. Spermatozoa were analysed by flow cytometry to characterize X- and Y-chromosome-bearing sperm populations and to quantify the DNA difference between them. Two symmetrical, overlapping and clearly separated peaks, corresponding to X- and Y-bearing spermatozoa, were detected. The difference in fluorescence intensity between the peaks was 4.4 +/- 0.03% without any significant inter- or intra-animal variations. Therefore, the identification and selection of high-purity samples of sperm populations for sex sorting is easier in bucks compared with other domestic species.     

Review: The strobilurin fungicides

The original article to which this Correction refers was published in Pest Management Science 58 (7): 649–662 (2002).Copyright © 2004 Society of Chemical Industry     

Equine pituitary pars intermedia dysfunction: current understanding and recommendations from the Australian and New Zealand Equine Endocrine Group

The purpose of this article is to provide a review of the current knowledge and opinions about the epidemiology, clinical findings (including sequelae), diagnosis, treatment and monitoring of equine pituitary pars intermedia dysfunction, particularly in the Australian context. This information and the recommendations provided will assist practitioners in making informed decisions regarding the diagnosis and management of this disorder.     

Effect of bovine seminal plasma on bovine endometrial epithelial cells in culture

The purpose of this study was to investigate the effect of seminal plasma (SP) from bulls of known fertility on bovine endometrial epithelial cells (bEEC) in culture. The bEEC from passage 5, approximately 5.0–13 × 10⁵ cells per flask, were challenged with SP from bulls of high or low fertility (n = 3 and 2, respectively) or PBS (control), at 1% (75 μl) or 4% (300 μl) and were incubated for 72 hr (n = 13 per challenge). Total cell number and viability of bEEC after challenge with 1% SP from either high‐ or low‐fertility bulls (75H or 75L, respectively) did not differ from controls. In contrast, challenge with 4% of SP from high‐ or low‐fertility bulls (300H or 300L) negatively affected bEEC cell number and viability. Challenge with 300 L had a greater adverse effect than 300H. These results suggest that the negative effect of bovine SP on bEEC is both dose‐dependent and fertility‐dependent.     

A framework for evaluation of on-farm mastitis diagnostics in Australia

Numerous culture-based diagnostics are available on the Australian and international markets for on-farm detection of bacterial pathogens in milk. Use of such diagnostics may provide an opportunity to improve the prudent use of antimicrobials in udder health management. Farms are low-resource settings in terms of diagnostic microbiology capacity. The World Health Organisation has identified criteria for the evaluation of diagnostic tests in low resource settings based on Accuracy, Sensitivity, Specificity, User-friendliness, being Rapid or Robust, Equipment-free and being Deliverable (ASSURED). Here, we review how those criteria can be interpreted in the context of microbiological diagnosis of mastitis pathogens, and how on-farm diagnostics that are currently available in Australia perform relative to ASSURED criteria. This evaluation identifies multiple trade-offs, both with regard to scientific criteria and with regards to convenience criteria. More importantly, the purpose of testing may differ between farms, and test performance should be evaluated relative to its intended use. The ability of on-farm mastitis diagnostics to inform mastitis treatment decision-making in a timely and cost-effective manner depends not just on test characteristics but also on farm-specific pathogen prevalence, and on the farm enterprise's priorities and the farm manager's potential courses of action. With most assay evaluations to date conducted in professional laboratories, there is a surprising dearth of information on how well any of the diagnostic tests perform on-farm and, indeed, of the on-farm decision-making processes that they aim to inform.     

The effect of intra-articular methylprednisolone acetate and exercise on equine carpal subchondral and cancellous bone microhardness

Dorsal carpal osteochondral injury is a major cause of lameness in horses undergoing high intensity training. Intra-articular corticosteroid treatment is used commonly to manage exercise-associated articular pain, but its use remains highly controversial in the equine athlete. This project, therefore, aimed to compare the mechanical properties of intra-articular MPA and diluent-treated middle carpal subchondral and cancellous bone in horses undergoing a short-term treadmill exercise programme. It was hypothesised that subchondral and cancellous bone mechanical properties are influenced by intra-articular administration of methylprednisolone acetate (MPA). Eight 2-year-old female horses had MPA or diluent administered into contralateral middle carpal joints at 14 day intervals, for a total of 4 treatments per horse. Horses underwent a standard treadmill exercise protocol until euthanasia (Day 70). Standard sites were located on the dorsal aspect of third, radial and intermediate carpal bones. Osteochondral samples from each test site were divided into subchondral bone and cancellous bone portions. These were dried, resin-embedded and gold-coated. Microhardness measurements were obtained at each test site. No significant effect of intra-articular treatment was detected. At each site, cancellous bone trabecular struts had an 18-19% higher microhardness value than the overlying subchondral bone. These findings indicate that intra-articular administration of MPA at this dose has no effect on subchondral or cancellous bone adaptation to short-term exercise and, therefore, on the propensity of carpal bones to injury. Further investigation into the calcified cartilage layer, effect of different corticosteroid preparations and diffusion of medication are required.     

Endometrial Adenocarcinoma and Mucometra in a 6-year-old Alaska Malamute Dog

A 6-year-old female Alaska Malamute dog was presented for evaluation of abdominal enlargement referred by a local veterinarian. On the history, the owner complained of chronic abdominal enlargement initiated more than 4 months ago, reduced appetite, occasional vomiting and general dullness. He also complained of greenish mucous intermittent vaginal discharge starting 10 days ago. The bitch was chronically treated with medroxiprogesterone acetate. A laparatomy was performed and fluid in the abdomen was found and aspirated during the surgery. Also a very fluid-filled distended uterus and a mass in the distal part of the left uterine horn were found. The mass was encapsulated by the omentum, but areas of necrosis and calcification were identified. Histopathological diagnosis was endometrial adenocarcinoma.