Microbiology Commons^™

Microbial Interactions Between Compost Bedded Pack Barn Bedding And Teat Exposure In Transition Dairy Cattle, Tanya Lynn France

Theses and Dissertations--Animal and Food Sciences

Compost bedded pack barns utilize composting methods which provide a soft surface for dairy cows to lie on. This requires optimal microbial growth, which may increase the exposure of mastitis-causing pathogens to the teats of early lactation animals. Bedding characteristics, bedding bacteria, and bacterial counts on the teat skin, teat ends, and in the milk of early lactation dairy cows housed on a compost bedded pack were assessed over a 6-month time. The main objective was to determine the relationship between environmental effects (bedding characteristics and weather conditions) and cow-level (teat skin, teat end, milk) bacteria counts over time in …

Effect Of Maternal Diet On Select Fecal Bacteria In Mares And Their Foals, Morgan Brewer Pyles

Theses and Dissertations--Animal and Food Sciences

The process of microbial colonization in the gastrointestinal tract of foals and the factors influencing this process are not well understood. The objectives were to determine the effect of starch source in pelleted concentrates in the maternal diet on select fecal bacterial groups in mares and their foals and to evaluate changes in these bacterial groups over time. Thoroughbred foals (n=19) were from dams fed one of two concentrates: an oat-based (OB) or corn and wheat middling-based (CWB) pelleted concentrate. Fecal samples were collected from mares at 324 d of gestation, pre-foaling, 1 d, 14 d, and 28 d after …

Antimicrobial Efficacy Of Natural Bioactive Compounds And High Pressure Processing Against Potential Pathogens In Infant Foods, Hayriye Cetin-Karaca

Theses and Dissertations--Animal and Food Sciences

This study investigated the antimicrobial efficacy of bioactive plant compounds along with high pressure processing (HPP) against pathogens Bacillus cereus and Cronobacter sakazakii in infant formula and infant rice cereal. The influence of these applications on antimicrobial activity, shelf-life and sensory attributes of infant foods were examined.

Trans-cinnamaldehyde (TC), (-)-Epigallocatechin gallate (EGCG) and [10]-Gingerol (GI) were incorporated (0.05%) in infant rice cereal reconstituted with infant formula. The cereal was inoculated with either B. cereus (ATCC 14579) or B. cereus spores (10⁷-10⁸ log CFU g^-1). All the samples were stored at 7, 23 or 37°C for …

The Acoustic Emissions Produced By Escherichia Coli During The Growth Cycle, Traci Jane Cox

Theses and Dissertations--Animal and Food Sciences

The objective of this study was to determine if acoustic emissions (AE) generated by three strains of Escherichia Coli (5024-parent strain, 8279-mutant strain and 8279-random/unrelated strain) could be used to differentiate each strain during their growth cycle. An acoustic sensor with an operating range of 35 kHz-100 kHz was inserted into the growth vessel and attached to a selected channel to capture AE data. The growth vessel was loaded with 60 ml of tryptic soy broth (TSB) (0.25% fructose) media with alginate (1.1%) or without alginate and inoculated with 1% (10⁸ CFU/ml) of an E. coli strain. The growth …

Antilisterial Characteristics Of Volatile Essential Oils, Leeann L. Slaughter

Theses and Dissertations--Animal and Food Sciences

This study explored the in vitro and in situ antilisterial inhibitory activity of 16 essential oils during indirect exposure: Spanish Basil oil (Ocimum basilicum), Bay oil (Pimenta racemosa), Italian Bergamot oil (Citrus bergamia), Roman Chamomile oil (Anthemis nobilis), Sir Lanka Cinnamon oil (Cinnamomum zeylanicum), Citral, Clove Bud oil (Syzygium aromaticum), Cumin Seed oil (cuminum cyminum), Eucalyptus oil (Eucalyptus globulus), Eugenol, Geranium extract (Pelargonium graveolens), Marjoram oil (Origanum majorana), Neroli extract (Citrus aurantium), Peppermint oil (Mentha piperita L.), …

Changes To The Equine Hindgut Microflora In Response To Antibiotic Challenge, Brittany E. Harlow

Theses and Dissertations--Animal and Food Sciences

Antibiotics are important to equine medicine, but can cause detrimental side-effects including reduced feed intake, allergic reactions, and diarrhea. Antibiotic-associated diarrhea (AAD) is attributed to disruption of the hindgut microflora, permitting proliferation of pathogenic microbes. The objectives were to evaluate the effects of antibiotics on beneficial fecal bacteria, AAD-associated pathogens, microbial species richness and fermentation. Horses were assigned to treatment groups: control (no antibiotics, n=6), trimethoprim-sulfadiazine (oral, n=6), or sodium ceftiofur (IM, n=6). Fecal samples were taken during adaptation (3 wk), antibiotic challenge (1 wk), and withdrawal (1 wk). Fecal cellulolytics decreased by >99% during challenge and did not recover …

The Effects Of Slow Release Urea On Nitrogen Metabolism In Cattle, Vaughn B. Holder

Theses and Dissertations--Animal and Food Sciences

The objective of this research was to investigate the effects of slow release urea on N metabolism in cattle. The ruminal behavior of Optigen®II and the effect of basal diet on the in situ degradability of urea and Optigen®II were evaluated. The effect of slow release urea and its interaction with degradable intake protein (DIP) level in the diet on N retention and excretion was evaluated utilizing 8 Holstein steers in a 4 x 4 Latin square experiment. In addition, the effect of slow release urea and DIP level on ruminal and systemic urea kinetics was evaluated using stable isotope …