Browsing by Subject "Dairy cattle"

Now showing 1 - 5 of 5
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    53rd Minnesota Nutrition Conference, proceedings, September 22-23, 1992, Bloomington, Minnesota.
    (University of Minnesota: Minnesota Extension Service and Dept. of Animal Science, 1992-09-22)
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    Alternative practices in organic dairy and broiler production and their effects on animal behavior, health, and welfare
    (2021-08) Phillips, Hannah
    The animal welfare of organic livestock is a major interest among producers, the public, researchers, and veterinarians. This dissertation presents the results from 5 experiments conducted between 2016 and 2020 on a research farm at the University of Minnesota West Central Research and Outreach Center in Morris. The experiments were designed to investigate novel practices in organic livestock production and their potential efficacy on improving animal welfare. These results include information on the efficacy of herbal pain management therapies for disbudded dairy calves, methods to prevent distress and mastitis in transitioning dairy heifers, efficacy of broilers to control face fly larva, and effects of outdoor stocking density on behaviors of free-range broilers. To summarize the results of ineffective practices, the tested herbal tincture did not reduce pain in disbudded calves, white willow bark did not reduce inflammatory biomarkers in calves, and broiler chickens did not reduce the survival of face fly larva in cow manure. To summarize the results of effective practices, teat dipping and acclimating heifers to the milking parlor 3 weeks prior to calving improved milking behaviors and reduced Staphylococcus aureus intramammary infections in heifers over the first 3 days after calving. Furthermore, additional outdoor space for free-broiler chickens reduced aggressive attacks and reduced some rarely observed behaviors that are akin to discomfort. To conclude, experiments on the novel topics discussed in this dissertation serve as a foundation for future comprehensive investigations related to practices that affect the animal welfare of organic livestock.
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    Environmental characteristics and animal welfare of two new dairy housing options in the Upper Midwest.
    (2010-12) Lobeck, Karen Marie
    Summary abstract not available.
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    Molecular Epidemiology of Foodborne Zoonotic Pathogens at the Rodent-Agriculture Interface
    (2021-12) Jahan, Nusrat
    Wild mammals are reservoirs for a growing number of emerging infectious zoonotic diseases. In particular, wild rodents are well-known reservoirs and vectors for a wide range of viruses and bacteria that cause illness in humans, including foodborne pathogens. It is critical to understand the role that rodents play in emerging zoonotic disease because they are commonly associated with humans, especially as pests throughout our agricultural production systems. Although numerous studies document a link between rodent pests on farms and outbreaks of foodborne pathogens (e.g., E. coli O157, Salmonella, etc.) in Europe and Asia, comparatively little research has focused on the rodent-agricultural interface in the United States. Knowing this, the functional role that rodent pests serve in the amplification and transmission of zoonotic foodborne pathogens is poorly understood in the United States. Given this knowledge gap, my dissertation research is novel in that it will provide a new and unexplored dimension of the rodent-Ag interface in one of the most agriculturally productive regions in the United States, the Midwest. My objective is to test the hypothesis that peridomestic rodents, inhabiting food animal farms, are reservoirs and amplifiers of zoonotic foodborne pathogens and antibiotic resistant bacteria that threaten food production systems and public health initiatives.We used a robust combination of mammalogy field methods, cutting-edge next generation sequencing, and traditional microbiological techniques to discover rodent-borne pathogens circulating on food animal farms. We collected rodents from food animal farms in MN and WI, identified the rodent species, and conduct metagenomic surveillance of putative foodborne pathogens from rodent feces. With the completion of this goal we were be able to describe rodent species diversity in different food animal farms and characterized the metagenomic bacterial community of rodent feces with passive screening for presence of putative zoonotic foodborne pathogens. We then phenotypically characterized rodent fecal isolates including antibiotic resistant Escherichia coli and Shiga-toxin producing E. coli (STEC) using traditional microbiological and molecular methods. We applied whole genome sequencing (WGS) to confirm their virulence traits (e.g., virulence genes, sequence types, serotypes, plasmid) and antibiotic resistance. We utilized a robust combination of comparative genomics and phylogenetic methods to analyze the resulting WGS data. Additional phylogenetic analyses were conducted in the context of relevant human and food animal pathogens of clinical origin gathered from publicly available databases. Successful completion of this goal enabled us to describe the molecular epidemiology of rodent associated zoonotic foodborne pathogens and how closely related or distant the rodent isolates were from human or animal origin (i.e., based on phylogenetic evolutionary relationships). Data generated from my dissertation research has filled an important knowledge gap regarding connections between the rodent-Ag interface and food safety in the two Midwestern states. Furthermore, we provided baseline data on the potential foodborne pathogens and AMR carried by rodents, which can be effectively used to inform public health officials, epidemiologists and farmers in order to improve rodent-associated biosecurity and protect our food supply.