The spread of bovine tuberculosis in Canadian shared pastures: Data, model, and simulations.

Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a chronic disease typical of cattle. Nonetheless, it can affect many mammals including humans, making it one of the most widespread zoonotic diseases worldwide. In industrialized countries, the main pathways of introduction of bTB into a herd are animal trade and contact with infected wildlife. In addition, for slow-spreading diseases with a long latent period such as bTB, shared seasonal pastures might be a between-herd transmission pathway, indeed farmers might unknowingly send infected animals to the pasture, since clinical signs are rarely evident in early infection. In this study, we developed a dynamic stochastic model to represent the spread of bTB in pastures. This was tailored to Canadian cow-calf herds, as we calibrated the model with data sourced from a recent bTB outbreak in Western Canada. We built a model for a herd with seasonal management, characterized by its partition into a group staying in the main facility and the remaining group(s) moving to summer pastures. We used this model to estimate the time of the first introduction of bTB into the herd. Furthermore, we expanded the model to include herds categorized as high-risk contacts with the index herd, in order to estimate the potential for disease spread on shared pastures. Finally, we explored two control scenarios to be applied to high-risk farms after the outbreak detection. Our results showed that the first introduction likely happened 3 to 5 years prior to the detection of the index herd, and the probability of bTB spreading in pastures was low, but not negligible. Nevertheless, the surveillance system currently in place was effective to detect potential outbreaks.

Outbreak investigation of porcine epidemic diarrhea in swine in Ontario.

Porcine epidemic diarrhea virus was first diagnosed in Ontario in January of 2014. An outbreak investigation was conducted and it was hypothesized that feed containing spray-dried porcine plasma contaminated with the virus was a risk factor in the introduction and spread of the disease in Ontario.

Enquête sur l'éclosion de la diarrhée porcine épidémique chez les porcs de l'Ontario. Le virus de la diarrhée épidémique porcine a été diagnostiqué pour la première fois en Ontario en janvier 2014. Une enquête a été réalisée sur l'éclosion et on a émis l'hypothèse que les aliments contenant du plasma porcin séché par atomisation contaminé par le virus représentait un facteur de risque pour l'introduction et la propagation de la maladie en Ontario.(Traduit par Isabelle Vallières).

A study of 55 field cases of uterine torsion in dairy cattle.

Two-hundred and seventy-three animals were enrolled in a case-case comparison of uterine torsions and other dystocias. The purpose of the study was to describe field cases of uterine torsion and their clinical management, compare them with other types of dystocia attended by field veterinarians, and evaluate the effect of season and housing on the incidence of torsions. Fifty-five cases of uterine torsions representing 20% of the dystocias were diagnosed. Most cases of uterine torsion were successfully corrected and followed by the vaginal delivery of a live calf. When compared with other types of dystocia, cows were at greater risk for uterine torsion than were heifers (OR = 5.2; P < 0.0001), while animals suffering from fetopelvic disproportion or carrying twins were at a lesser risk (OR = 0.05; P < 0.0001 and OR = 0.09; P = 0.007, respectively). Heifers had a lower risk when calving alone in a pen versus a tie-stall (OR = 0.2, P = 0.04). There was no significant effect of season on the risk of uterine torsion.

Routine surgical procedures in dairy cattle under field conditions: abomasal surgery, dehorning, and tail docking.

This article discusses the different methods used for the correction of left displaced abomasum. The advantages, disadvantages, and success rates of each technique are reviewed. The most common complications are described, and the economics of repeat surgery after a failed left displaced abomasum repair are examined. This article also addresses the need for anesthesia when dehorning and tail docking dairy cattle. The justifications for routine use of these two procedures are discussed, mainly from an animal welfare standpoint.