Browsing by Author "Pearson, Jennifer"

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    Consequences of Testicular Heat Stress and Potential Amelioration Strategies
    (2023-01-12) Mohamed, Abdallah Mohamed Shahat; Kastelic, John; Kovalchuk, Igor; Pajor, Edmond; Pearson, Jennifer; Thundathil, Jacob; de Graaf, Simon; Honaramooz, Ali
    Heat stress (HS) is a worldwide problem due to temperature elevations associated with global warming. Monitoring temperature changes in testes and scrotum over time is important to understand thermoregulatory capacity of testes and scrotum. Temperature data loggers (DLs) are reliable devices that can be implanted in scrotal subcutaneous tissues to serially record intrascrotal temperature without altering animal behavior. Testicular HS causes a variety of outcomes, depending on the degree and duration of testicular heating. Some effects of testicular HS on testicular tissues, blood flow and sperm quality and attempts to prevent them, by treating animals or semen extender, have been reported. The overall objective of this study was to investigate impacts of HS on sperm quality and use various ameliorative strategies to mitigate these detrimental effects, using bull and ram models. We validated data loggers as a reliable, less invasive and serial method to measure intrascrotal temperature. Scrotal subcutaneous temperature was significantly increased by scrotal insulation or whole-body heating, but not by scrotal neck insulation; however, all three heat-stress models decreased sperm motility and morphology in bulls and rams. In addition, our hypothesis that melatonin or L-arginine improve quality of frozen-thawed sperm from HS rams was supported; 1 mM of either gave best results, except 0.5 mM minimized DNA Fragmentation Index (DFI%). Moreover, during hot weather, bulls voluntarily accessed shade, significantly lowering scrotal subcutaneous temperatures and improving sperm quality. In rams exposed to testicular HS, slow-release melatonin significantly improved testicular blood flow, protected sperm motility and morphology, and lessened HS-induced reductions in post-thaw sperm quality. Therefore, melatonin has potential for mitigating effects of testicular HS under field conditions.
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    Detection of Johne’s Disease on dairy farms using different qPCR target genes for Mycobacterium avium subsp. paratuberculosis in young stock
    (2023-08) Martins, Larissa; Barkema, Herman W.; Orsel, Karin; De Buck, Jeroen; Pearson, Jennifer
    Young stock can shed Mycobacterium avium subspecies paratuberculosis (MAP) in feces, present antibody titers and transmit MAP to other young stock. However, most Johne’s disease (JD) control programs do not include young stock in MAP testing strategies, which might be one of the reasons why only a few JD control programs were able to eradicate MAP. This study aimed to include young stock in a JD testing strategy and improve diagnostic tests. A literature review conducted reported that young stock can shed MAP as early as 4 mo of age. However, due to the chronic characteristic of the disease, it was considered important to improve current diagnostic tests and develop new tests, such as phage-based and metabolomics tests. A tentative inclusion of young stock in the MAP testing strategy was evaluated based on direct fecal qPCR and ELISA every 2 mo from animals between 2-12 mo of age. A sudden rise in MAP prevalence was detected at the second sampling, 2 mo after the start of the study. Although the high MAP prevalence was explained in part by the presence of MAP infections in the herd, it was not possible to explain the specificity of the ISMAP02 gene, which raises doubts about different Mycobacterium species being detected by the same assay. Furthermore, an in depth evaluation of the main MAP target genes for qPCR assays was proposed across different sample types and MAP concentrations. Overall, all MAP target genes were able to detect samples with high MAP concentration. IS900 and ISMAP02 consistently identified MAP in all sample types. However, the genes mbtA, hspX and F57 presented issues to detect samples with mid to low MAP concentrations.
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    Protocol for a scoping review of precision technologies for cattle monitoring
    (2022-07-20) Besler, Brendon; Mojabi, Pedram; Murphy, James E; Wang, Zefang; Baker, Ryan; Pearson, Jennifer; Fear, Elise
    Livestock farming has increased in complexity considerably due to the increased demand for animal products combined with a decreasing number of farmers and ranchers. To meet this challenge, Precision Livestock Farming (PLF) aims to develop fully automated tools that continuously monitor animals, such as cattle. Ineffective cattle management can have significant animal welfare implications, as well as financial consequences for both farmers and the economy because of the size of this substantial industry globally. To our knowledge, no scoping review with explicit published search protocol has broadly examined PLF technologies for both beef and dairy cattle to identify gaps in current research.