Browsing by Author "Campbell, John R."

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    Impacts of calving management, calf risk factors, and difficult calvings on health and performance of beef calves
    (2019-08-28) Pearson, Jennifer M.; Windeyer, M. Claire; Pajor, Edmond Anthony; Campbell, John R.; Caulkett, Nigel; Lévy, Michael Z.
    Calf health and survival is crucial to successful cow-calf operations. Assisted calves are at a disadvantage compared to their herdmates because they may be injured, oxygen deprived, or less vigorous at birth. Determining evidence-based management practices to mitigate the effects of calving assistance on calf health and survival, as well as investigating risk factors associated with assisted calvings that affect transfer of passive immunity (TPI), morbidity, mortality, and growth, will help improve calf wellbeing. Therefore, the objectives of this thesis were to: benchmark the incidence of calving assistance and health outcomes, and describe current calving and colostrum management practices; to determine the impacts of subclinical trauma on calf vigour and TPI; and to investigate the impact of implementing pain mitigation at birth to assisted beef calves. Chapter 2 described current calving and colostrum management practices found on western Canadian cow-calf operations. Although the incidence of assisted calvings was low, the majority of producers assisted at least one calving, indicating the importance of understanding intervention and management strategies in compromised calves such as those assisted at birth. Chapter 3 quantified subclinical trauma associated with the degree of calving difficulty, and evaluated associations between subclinical trauma and calf vigour and TPI. Calves experiencing difficult births had elevated levels of subclinical trauma and decreased vigour. Subclinical trauma and reduced vigour were also associated with inadequate TPI. Chapters 4 and 5 investigated the clinical impacts of administering a non-steroidal anti-inflammatory drug to assisted beef calves at birth. In Chapter 4, calves administered meloxicam had greater average daily gain in the first week of life compared to placebo treated calves, but no effect was seen on pain and inflammatory mediators, vigour, TPI, health, or weaning growth. In Chapter 5, there was no effect of administering meloxicam to assisted calves on TPI, health, or growth, but vigour assessment and colostrum management were found to be important management tools associated with TPI, calf health, and growth. Therefore, calves assisted at birth experience subclinical trauma that affects their vigour and TPI. Pain mitigation strategies, vigour assessment, and colostrum management may be important tools to improve wellbeing in assisted beef calves.
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    Regional heterogeneity and unexpectedly high abundance of Cooperia punctata in beef cattle at a northern latitude revealed by ITS-2 rDNA nemabiome metabarcoding
    (2022-01-06) De Seram, Eranga L.; Redman, Elizabeth M.; Wills, Felicity K.; de Queiroz, Camila; Campbell, John R.; Waldner, Cheryl L.; Parker, Sarah E.; Avramenko, Russell W.; Gilleard, John S.; Uehlinger, Fabienne D.
    Abstract Background The species composition of cattle gastrointestinal nematode (GIN) communities can vary greatly between regions. Despite this, there is remarkably little large-scale surveillance data for cattle GIN species which is due, at least in part, to a lack of scalable diagnostic tools. This lack of regional GIN species-level data represents a major knowledge gap for evidence-based parasite management and assessing the status and impact of factors such as climate change and anthelmintic drug resistance. Methods This paper presents a large-scale survey of GIN in beef herds across western Canada using ITS-2 rDNA nemabiome metabarcoding. Individual fecal samples were collected from 6 to 20 randomly selected heifers (n = 1665) from each of 85 herds between September 2016 and February 2017 and 10–25 first season calves (n = 824) from each of 42 herds between November 2016 and February 2017. Results Gastrointestinal nematode communities in heifers and calves were similar in Alberta and Saskatchewan, with Ostertagia ostertagi and Cooperia oncophora being the predominant GIN species in all herds consistent with previous studies. However, in Manitoba, Cooperia punctata was the predominant species overall and the most abundant GIN species in calves from 4/8 beef herds. Conclusions This study revealed a marked regional heterogeneity of GIN species in grazing beef herds in western Canada. The predominance of C. punctata in Manitoba is unexpected, as although this parasite is often the predominant cattle GIN species in more southerly latitudes, it is generally only a minor component of cattle GIN communities in northern temperate regions. We hypothesize that the unexpected predominance of C. punctata at such a northerly latitude represents a range expansion, likely associated with changes in climate, anthelmintic use, management, and/or animal movement. Whatever the cause, these results are of practical concern since C. punctata is more pathogenic than C. oncophora, the Cooperia species that typically predominates in cooler temperate regions. Finally, this study illustrates the value of ITS-2 rDNA nemabiome metabarcoding as a surveillance tool for ruminant GIN parasites. Graphical Abstract