Browsing by Author "Goldhawk, Christy"

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    An experimental model to induce digital dermatitis in beef calves
    (2022-06-23) Thomas, Anice D.; Pajor, Edmond A.; Caddey, Benjamin; Goldhawk, Christy; Martins, Larissa; Orsel, Karin
    Abstract Background Digital dermatitis (DD) is a multifactorial infectious disease affecting the skin on feet of cattle causing erosion and inflammation above the heel bulbs. Some cases of DD cause lameness and significantly impact animal welfare and productivity. While DD has emerged as a concern for the beef industry, key information regarding early detection and its impact on cattle behaviour is lacking. The primary objective of this study was to determine if an established DD experimental model for dairy calves could be used to induce DD lesions in beef calves. A secondary objective was to describe changes in behaviour and pain associated with induction of DD lesions. Eight beef calves acquired from a single cow-calf operator were enrolled in the study. Upon enrolment, calves were evaluated and determined to be free of foot lesions. Within the experimental environment, calves were housed in individual pens and assigned to two groups (mock-inoculated and inoculated). Both hind feet of each calf were enrolled. Within calf, inoculation protocol was consistent, and a 28-day experimental protocol was employed. Two days prior to inoculation, both hind feet of each calf were abraded (area above the heel bulbs and below the dewclaws), moistened, and wrapped to facilitate an anaerobic condition. Feet were inoculated with macerated DD lesion material or mock inoculum and remained wrapped until clinical signs of DD or protocol endpoint. Results After a period of 14 to 18 days post inoculation, three of five inoculated calves developed clinical signs (lameness), and upon close inspection, DD lesions were present on at least one hind foot. Two of five inoculated calves did not develop lesions within 28 days. Zero of three mock-inoculated calves developed DD. Treponema spp. were detected by quantitative polymerase chain reaction from biopsies of induced lesions. Measurements of behaviour prior to disease induction were numerically different between DD affected and mock-inoculated calves. Conclusions An experimental infection model established for dairy cattle was used to successfully induce acute DD lesions in three of five inoculated beef calves. This model can provide a framework to study intervention protocols and to evaluate the impact of DD on behaviour and pain.
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    Calf and human perspectives about handling and restraint during western Canadian beef calf processing events
    (2023-01-23) Arkangel, Lindsey; Pajor, Ed; Windeyer, Claire; Adams, Cindy; Goldhawk, Christy
    Beef calf processing involves individually handling and restraining calves for procedures such as castration, branding, and vaccination. It also serves an important sociocultural purpose for those in the ranching community. The method by which people handle and restrain calves during processing differs among operations. In western Canada, the most common methods are roping and wrestling (RW), roping and Nord fork (RNF), and using a tilt table (TT). However, the calf welfare implications of these methods, as well as how these common methods are perceived by participants in western Canadian beef calf processing events, are unknown. The first study (Chapter 2) compared the effects of the three common methods of handling and restraint (i.e., RW, RNF, and TT) used to process calves on behavioural indicators associated with calf welfare. It was found that overall, differences detected in the effect of these methods on various indicators during processing were inconsistent. After processing, RNF calves displayed the highest rates of foot stomping, followed by RW calves, then TT calves. This was the first study to evaluate the effects of common handling and restraint methods used in western Canadian beef calf processing events on behavioural indicators associated with calf welfare, as well as include the roping and Nord fork method. The second study (Chapter 3) described how people who participate in processing events perceive common handling and restraint methods used for pre-weaned beef calves on western Canadian cow-calf operations. In this study, it was revealed that participants in western Canadian beef calf processing events prefer the roping and wrestling method the most and the tilt table the least. However, the underlying values behind participants’ indicated preferences shared much in common. Specifically, the values of calf safety and minimizing calf stress, efficiency, convenience, and human safety and limiting labour intensity were shared by many participants when considering handling and restraint methods for processing, regardless of their noted preferences. This was the first time the current perceptions of participants in western Canadian beef calf processing events regarding the common handling and restraint methods were described.
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    Microclimate During Beef Cattle Transport: Effects of Transportation Management and Relationship to Indicators of Animal Welfare
    (2014-06-11) Goldhawk, Christy; Pajor, Ed
    The consequences of transportation on cattle welfare have become focal areas of concern within North America. However, there is an absence of empirical evidence to inform decisions and risk management under commercial conditions. The objective of this thesis was to evaluate a system for monitoring in-transit microclimate within commercial transport trailers, and subsequently assess the relationships between transportation management factors, such as space allowance and location within trailer, microclimate during commercial transport, and indicators of cattle welfare for three target populations in the beef industry; calves, feeders, and cull cows. Twenty-four loads of calves, 19 loads of feeders, and 17 loads of cull cows were used for data collection, all under commercial conditions within North America. A logger layout of 10 loggers distributed at the ceiling-level was deemed most appropriate for research applications due to consistency of performance with different cattle weights and space allowances in two compartments used to transport the majority of cattle in North America. Single logger layouts were an economical alternative if ambient conditions were considered. Predictive equations are presented that can serve as estimates of correction factors when using ambient temperature and humidity as proxy for animal-level conditions during transportation. Hazard assessment provided quantification of trailer microclimate during commercial cattle transport for the target populations. Space allowance and location within trailers did not have a consistent effect on the in-transit microclimate. However, in accordance with previously published reports on vehicle design, vehicle speed and ambient conditions were associated with trailer microclimate in each study. Additionally, evidence was presented that refutes the hypothesis that the use of boarding in the winter negatively influences ventilation during transport, although stationary periods remain of concern. The majority of indicators of cattle welfare support the inference that the effect of in-transit temperature on indicators of cattle welfare is dependent on the temperature acclimatization of cattle prior to transport, and physiological indicators were all within the ranges expected for healthy cattle. The results of the three studies presented herein appear to support that, relative to the indicators of cattle welfare evaluated, the space allowances used by the North American beef industry are not detrimental to cattle welfare or meat quality.